remove packetPendingRMT from wrong if

Update examples

.gitattributes

@@ -1,2 +1,3 @@
 # Auto detect text files and perform LF normalization
 * text=auto
+*.svg -text

.github/workflows/main.yml

@@ -12,7 +12,7 @@ jobs:
     - name: Install Python Wheel
       run: pip install wheel
     - name: Install PlatformIO Core
-      run: pip install -U https://github.com/platformio/platformio/archive/v4.2.1.zip
+      run: pip install -U platformio
     - name: Copy generic config over
       run: cp config.example.h config.h
     - name: Compile Command Station (AVR)

.github/workflows/sha.yml

@@ -0,0 +1,34 @@
+name: SHA 
+
+# Run this workflow ever time code is pushed to a branch
+# other than `main` in your repository
+on: push
+
+jobs:
+  # Set the job key. The key is displayed as the job name
+  # when a job name is not provided
+  sha:
+    # Name the Job
+    name: Commit SHA 
+    # Set the type of machine to run on
+    runs-on: ubuntu-latest
+
+    if: github.ref == 'refs/heads/master'
+    steps:
+      # Checks out a copy of your repository on the ubuntu-latest machine
+      - name: Checkout code
+        uses: actions/checkout@v2
+      
+      - name: Create SHA File
+        run: |
+          sha=$(git rev-parse --short "$GITHUB_SHA")
+          echo "#define GITHUB_SHA \"$sha\"" > GITHUB_SHA.h
+
+      - uses: EndBug/add-and-commit@v4 # You can change this to use a specific version
+        with:
+          add: 'GITHUB_SHA.h'
+          message: 'Committing a SHA'
+
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # Leave this line unchanged
+          

.gitignore

@@ -6,4 +6,13 @@ Release/*
 .gcc-flags.json
 .pio/
 .vscode/
-config.h
+config.h
+.vscode/extensions.json
+mySetup.h
+mySetup.cpp
+myHal.cpp
+myAutomation.h
+myFilter.cpp
+myAutomation.h
+myFilter.cpp
+myLayout.h

ATMEGA2560/Timer.h

@@ -1,194 +0,0 @@
-#ifndef ATMEGA2560Timer_h
-#define ATMEGA2560Timer_h
-
-#include "../VirtualTimer.h"
-#include <Arduino.h>
-
-class Timer : public VirtualTimer {
-private:
-    int pwmPeriod;
-    unsigned long timer_resolution;
-    unsigned char clockSelectBits;
-    int timer_num;
-    unsigned long lastMicroseconds;
-public:
-void (*isrCallback)();
-    Timer(int timer_num) {
-        switch (timer_num)
-        {
-        case 1:
-        case 3:
-        case 4:
-        case 5:
-            timer_resolution = 65536;
-            break;
-        }
-        this->timer_num = timer_num;
-        lastMicroseconds = 0;
-    }
-
-    void initialize() {
-        switch (timer_num)
-        {
-        case 1:
-            TCCR1B = _BV(WGM13) | _BV(WGM12);
-            TCCR1A = _BV(WGM11);
-            break;
-        case 3:
-            TCCR3B = _BV(WGM33) | _BV(WGM32);
-            TCCR3A = _BV(WGM31);
-            break;
-        case 4:
-            TCCR4B = _BV(WGM43) | _BV(WGM42);
-            TCCR4A = _BV(WGM41);
-            break;
-        case 5:
-            TCCR5B = _BV(WGM53) | _BV(WGM52);
-            TCCR5A = _BV(WGM51);
-            break;
-        }
-    }
-
-    void setPeriod(unsigned long microseconds) {
-        if(microseconds == lastMicroseconds)
-            return;
-        lastMicroseconds = microseconds;
-        const unsigned long cycles = (F_CPU / 1000000) * microseconds;
-        if (cycles < timer_resolution) {
-            clockSelectBits = 1 << 0;
-            pwmPeriod = cycles;
-        } else
-        if (cycles < timer_resolution * 8) {
-            clockSelectBits = 1 << 1;
-            pwmPeriod = cycles / 8;
-        } else
-        if (cycles < timer_resolution * 64) {
-            clockSelectBits = (1 << 0) | (1 << 1);
-            pwmPeriod = cycles / 64;
-        } else
-        if (cycles < timer_resolution * 256) {
-            clockSelectBits = 1 << 2;
-            pwmPeriod = cycles / 256;
-        } else
-        if (cycles < timer_resolution * 1024) {
-            clockSelectBits = (1 << 2) | (1 << 0);
-            pwmPeriod = cycles / 1024;
-        } else {
-            clockSelectBits = (1 << 2) | (1 << 0);
-            pwmPeriod = timer_resolution - 1;
-        }
-
-        switch (timer_num)
-        {
-        case 1:
-            ICR1 = pwmPeriod;
-            TCCR1B = _BV(WGM13) | _BV(WGM12) | clockSelectBits;
-            break;
-        case 3:
-            ICR3 = pwmPeriod;
-            TCCR3B = _BV(WGM33) | _BV(WGM32) | clockSelectBits;
-            break;
-        case 4:
-            ICR4 = pwmPeriod;
-            TCCR4B = _BV(WGM43) | _BV(WGM42) | clockSelectBits;
-            break;
-        case 5:
-            ICR5 = pwmPeriod;
-            TCCR5B = _BV(WGM53) | _BV(WGM52) | clockSelectBits;
-            break;
-        }
-        
-    }
-    void start() {
-        switch (timer_num)
-        {
-        case 1:
-            TCCR1B = 0;
-            TCNT1 = 0;		// TODO: does this cause an undesired interrupt?
-            TCCR1B = _BV(WGM13) | _BV(WGM12) | clockSelectBits;
-            break;
-        case 3:
-            TCCR3B = 0;
-            TCNT3 = 0;		// TODO: does this cause an undesired interrupt?
-            TCCR3B = _BV(WGM33) | _BV(WGM32) | clockSelectBits;
-            break;
-        case 4:
-            TCCR4B = 0;
-            TCNT4 = 0;		// TODO: does this cause an undesired interrupt?
-            TCCR4B = _BV(WGM43) | _BV(WGM42) | clockSelectBits;
-            break;
-        case 5:
-            TCCR5B = 0;
-            TCNT5 = 0;		// TODO: does this cause an undesired interrupt?
-            TCCR5B = _BV(WGM53) | _BV(WGM52) | clockSelectBits;
-            break;
-        }
-        
-        
-    }
-    void stop() {
-        switch (timer_num)
-        {
-        case 1:
-            TCCR1B = _BV(WGM13) | _BV(WGM12);
-            break;
-        case 3:
-            TCCR3B = _BV(WGM33) | _BV(WGM32);
-            break;
-        case 4:
-            TCCR4B = _BV(WGM43) | _BV(WGM42);
-            break;
-        case 5:
-            TCCR5B = _BV(WGM53) | _BV(WGM52);
-            break;
-        }        
-    }
-
-    void attachInterrupt(void (*isr)()) {
-        isrCallback = isr;
-	    
-        switch (timer_num)
-        {
-        case 1:
-            TIMSK1 = _BV(TOIE1); 
-            break;
-        case 3:
-            TIMSK3 = _BV(TOIE3); 
-            break;
-        case 4:
-            TIMSK4 = _BV(TOIE4); 
-            break;
-        case 5:
-            TIMSK5 = _BV(TOIE5); 
-            break;
-        }   
-    }
-    
-    void detachInterrupt() {
-        switch (timer_num)
-        {
-        case 1:
-            TIMSK1 = 0; 
-            break;
-        case 3:
-            TIMSK3 = 0; 
-            break;
-        case 4:
-            TIMSK4 = 0; 
-            break;
-        case 5:
-            TIMSK5 = 0; 
-            break;
-        }  
-    }
-
-};
-
-extern Timer TimerA;
-extern Timer TimerB;
-extern Timer TimerC;
-extern Timer TimerD;
-
-
-
-#endif

ATMEGA328/Timer.h

@@ -1,208 +0,0 @@
-#ifndef ATMEGA328Timer_h
-#define ATMEGA328Timer_h
-
-#include "../VirtualTimer.h"
-#include <Arduino.h>
-
-class Timer : public VirtualTimer {
-private:
-    int pwmPeriod;
-    unsigned long timer_resolution;
-    unsigned char clockSelectBits;
-    int timer_num;
-    unsigned long lastMicroseconds;
-public:
-void (*isrCallback)();
-    Timer(int timer_num) {
-        switch (timer_num)
-        {
-        //case 0:
-        case 2:
-            timer_resolution = 256;
-            break;
-        case 1:
-            timer_resolution = 65536;
-            break;
-        }
-        this->timer_num = timer_num;
-        lastMicroseconds = 0;
-    }
-
-    void initialize() {
-        switch (timer_num)
-        {
-        // case 0:
-        //     TCCR0B = _BV(WGM02);
-        //     TCCR0A = _BV(WGM00) | _BV(WGM01);
-        //     break;
-        case 1:
-            TCCR1B = _BV(WGM13) | _BV(WGM12);
-            TCCR1A = _BV(WGM11);
-            break;
-        case 2:
-            TCCR2B = _BV(WGM22);
-            TCCR2A = _BV(WGM20) | _BV(WGM21);
-            break;
-        }
-    }
-
-    void setPeriod(unsigned long microseconds) {
-        if(microseconds == lastMicroseconds)
-            return;
-        lastMicroseconds = microseconds;
-        const unsigned long cycles = (F_CPU / 1000000) * microseconds;
-        
-        switch(timer_num) {
-        case 2:
-            if (cycles < timer_resolution) {
-                clockSelectBits = 1 << 0;
-                pwmPeriod = cycles;
-            } else
-            if (cycles < timer_resolution * 8) {
-                clockSelectBits = 1 << 1;
-                pwmPeriod = cycles / 8;
-            } else
-            if (cycles < timer_resolution * 32) {
-                clockSelectBits = 1 << 0 | 1 << 1;
-                pwmPeriod = cycles / 32;
-            } else
-            if (cycles < timer_resolution * 64) {
-                clockSelectBits = 1 << 2;
-                pwmPeriod = cycles / 64;
-            } else
-            if (cycles < timer_resolution * 128) {
-                clockSelectBits = 1 << 2 | 1 << 0;
-                pwmPeriod = cycles / 128;
-            } else
-            if (cycles < timer_resolution * 256) {
-                clockSelectBits = 1 << 2 | 1 << 1;
-                pwmPeriod = cycles / 256;
-            } else
-            if (cycles < timer_resolution * 1024) {
-                clockSelectBits = 1 << 2 | 1 << 1 | 1 << 0;
-                pwmPeriod = cycles / 1024;
-            } else {
-                clockSelectBits = 1 << 2 | 1 << 1 | 1 << 0;
-                pwmPeriod = timer_resolution - 1;
-            }
-            break;
-        //case 0:
-        case 1:
-            if (cycles < timer_resolution) {
-                clockSelectBits = 1 << 0;
-                pwmPeriod = cycles;
-            } else
-            if (cycles < timer_resolution * 8) {
-                clockSelectBits = 1 << 1;
-                pwmPeriod = cycles / 8;
-            } else
-            if (cycles < timer_resolution * 64) {
-                clockSelectBits = (1 << 0) | (1 << 1);
-                pwmPeriod = cycles / 64;
-            } else
-            if (cycles < timer_resolution * 256) {
-                clockSelectBits = 1 << 2;
-                pwmPeriod = cycles / 256;
-            } else
-            if (cycles < timer_resolution * 1024) {
-                clockSelectBits = (1 << 2) | (1 << 0);
-                pwmPeriod = cycles / 1024;
-            } else {
-                clockSelectBits = (1 << 2) | (1 << 0);
-                pwmPeriod = timer_resolution - 1;
-            }
-            break;
-        }
-
-        switch (timer_num)
-        {
-        // case 0:
-        //     OCR0A = pwmPeriod;
-        //     TCCR0B = _BV(WGM02) | clockSelectBits;
-        //     break;
-        case 1:
-            ICR1 = pwmPeriod;
-            TCCR1B = _BV(WGM13) | _BV(WGM12) | clockSelectBits;
-            break;
-        case 2:
-            OCR2A = pwmPeriod;
-            TCCR2B = _BV(WGM22) | clockSelectBits;
-            break;
-        }
-        
-    }
-    void start() {
-        switch (timer_num)
-        {
-        // case 0:
-        //     TCCR0B = 0;
-        //     TCNT0 = 0;		// TODO: does this cause an undesired interrupt?
-        //     TCCR0B = _BV(WGM02) | clockSelectBits;
-        //     break;
-        case 1:
-            TCCR1B = 0;
-            TCNT1 = 0;		// TODO: does this cause an undesired interrupt?
-            TCCR1B = _BV(WGM13) | _BV(WGM12) | clockSelectBits;
-            break;
-        case 2:
-            TCCR2B = 0;
-            TCNT2 = 0;		// TODO: does this cause an undesired interrupt?
-            TCCR2B = _BV(WGM22) | clockSelectBits;
-            break;
-        }
-        
-        
-    }
-    void stop() {
-        switch (timer_num)
-        {
-        // case 0:
-        //     TCCR0B = _BV(WGM02);
-        //     break;
-        case 1:
-            TCCR1B = _BV(WGM13) | _BV(WGM12);
-            break;
-        case 2:
-            TCCR2B = _BV(WGM22);
-            break;
-        }        
-    }
-
-    void attachInterrupt(void (*isr)()) {
-        isrCallback = isr;
-	    
-        switch (timer_num)
-        {
-        // case 0:
-        //     TIMSK0 = _BV(TOIE0); 
-        //     break;
-        case 1:
-            TIMSK1 = _BV(TOIE1); 
-            break;
-        case 2:
-            TIMSK2 = _BV(TOIE2); 
-            break;
-        }   
-    }
-    
-    void detachInterrupt() {
-        switch (timer_num)
-        {
-        // case 0:
-        //     TIMSK0 = 0; 
-        //     break;
-        case 1:
-            TIMSK1 = 0; 
-            break;
-        case 2:
-            TIMSK2 = 0; 
-            break;
-        }  
-    }
-
-};
-
-extern Timer TimerA;
-extern Timer TimerB;
-
-#endif

ATMEGA4809/Timer.h

@@ -1,131 +0,0 @@
-#ifndef ATMEGA328Timer_h
-#define ATMEGA328Timer_h
-
-#include "../VirtualTimer.h"
-#include <Arduino.h>
-
-// We only define behavior for timer 0 (TCA0), because TCB0 is very limited in functionality.
-
-class Timer : public VirtualTimer {
-private:
-    int pwmPeriod;
-    unsigned long timer_resolution;
-    unsigned char clockSelectBits;
-    int timer_num;
-    unsigned long lastMicroseconds;
-public:
-    void (*isrCallback)();
-    Timer(int timer_num) {
-        switch (timer_num)
-        {
-        case 0:
-            timer_resolution = 65536;
-            break;
-        }
-        this->timer_num = timer_num;
-        lastMicroseconds = 0;
-    }
-
-    void initialize() {
-        switch (timer_num)
-        {
-        case 0:
-            break;
-        }
-    }
-
-    void setPeriod(unsigned long microseconds) {
-        if(microseconds == lastMicroseconds)
-            return;
-        lastMicroseconds = microseconds;
-        const unsigned long cycles = (F_CPU / 1000000) * microseconds;
-        
-        switch(timer_num) {
-        case 0:
-            if (cycles < timer_resolution) {
-                clockSelectBits = 0x0;
-                pwmPeriod = cycles;
-            } else
-            if (cycles < timer_resolution * 2) {
-                clockSelectBits = 0x1;
-                pwmPeriod = cycles / 8;
-            } else
-            if (cycles < timer_resolution * 4) {
-                clockSelectBits = 0x2;
-                pwmPeriod = cycles / 32;
-            } else
-            if (cycles < timer_resolution * 8) {
-                clockSelectBits = 0x3;
-                pwmPeriod = cycles / 64;
-            } else
-            if (cycles < timer_resolution * 64) {
-                clockSelectBits = 0x5;
-                pwmPeriod = cycles / 128;
-            } else
-            if (cycles < timer_resolution * 256) {
-                clockSelectBits = 0x6;
-                pwmPeriod = cycles / 256;
-            } else
-            if (cycles < timer_resolution * 1024) {
-                clockSelectBits = 0x7;
-                pwmPeriod = cycles / 1024;
-            } else {
-                clockSelectBits = 0x7;
-                pwmPeriod = timer_resolution - 1;
-            }
-            break;
-        }
-
-        switch (timer_num)
-        {
-        case 0:
-            TCA0.SINGLE.PER = pwmPeriod;
-            TCA0.SINGLE.CTRLA = clockSelectBits << 1;
-            break;   
-        }     
-    }
-
-    void start() {
-        switch (timer_num)
-        {
-            case 0:
-                bitSet(TCA0.SINGLE.CTRLA, 0);
-                break;
-        }
-        
-        
-    }
-    void stop() {
-        switch (timer_num)
-        {
-        case 0:
-            bitClear(TCA0.SINGLE.CTRLA, 0);
-            break;
-        }        
-    }
-
-    void attachInterrupt(void (*isr)()) {
-        isrCallback = isr;
-	    
-        switch (timer_num)
-        {
-        case 0:
-            TCA0.SINGLE.INTCTRL = 0x1; 
-            break;
-        }   
-    }
-    
-    void detachInterrupt() {
-        switch (timer_num)
-        {
-        case 0:
-            TCA0.SINGLE.INTCTRL = 0x0; 
-            break;
-        }  
-    }
-
-};
-
-extern Timer TimerA;
-
-#endif

ATSAMC21G/Timer.h

@@ -1,129 +0,0 @@
-#ifndef ATSAMC21Timer_h
-#define ATSAMC21Timer_h
-
-#include "../VirtualTimer.h"
-#include <Arduino.h>
-
-class Timer : public VirtualTimer
-{
-private:
-    int pwmPeriod;
-    unsigned long timer_resolution;
-    unsigned long lastMicroseconds;
-public:
-    void (*isrCallback)();
-    Tcc* timer;
-
-    Timer(Tcc* timer) {
-        this->timer = timer;
-        if(timer == TCC0 || timer == TCC1) {
-            timer_resolution = 16777216;
-        } else {
-            timer_resolution = 65536;
-        }
-        lastMicroseconds = 0;
-    }
-
-    void initialize() {
-        if(timer == TCC0 || timer == TCC1) {
-            MCLK->APBCMASK.bit.TCC0_ = 1;
-            MCLK->APBCMASK.bit.TCC1_ = 1;
-            GCLK->GENCTRL[4].reg = ( GCLK_GENCTRL_DIV(2) | GCLK_GENCTRL_SRC_DPLL96M | GCLK_GENCTRL_IDC | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_OE );
-            while ((GCLK->SYNCBUSY.bit.GENCTRL >> 4)  & 1); // Wait for synchronization
-            GCLK->PCHCTRL[28].reg = ( GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN(4) );  // 28 = TCC0_TCC1
-            while ((GCLK->SYNCBUSY.bit.GENCTRL >> 4) & 1); // Wait for synchronization
-        } 
-        else if (timer == TCC2) {
-            MCLK->APBCMASK.bit.TCC2_ = 1;
-            GCLK->GENCTRL[5].reg = ( GCLK_GENCTRL_DIV(2) | GCLK_GENCTRL_SRC_DPLL96M | GCLK_GENCTRL_IDC | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_OE );
-            while ((GCLK->SYNCBUSY.bit.GENCTRL >> 5)  & 1); // Wait for synchronization
-            GCLK->PCHCTRL[29].reg = ( GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN(5) ); // 29 = TCC2
-            while ((GCLK->SYNCBUSY.bit.GENCTRL >> 5) & 1); // Wait for synchronization
-        }
-        
-        timer->WAVE.reg = TCC_WAVE_WAVEGEN_NPWM;             // Select NPWM as waveform
-        while (timer->SYNCBUSY.bit.WAVE);                    // Wait for synchronization
-
-    }
-    void setPeriod(unsigned long microseconds) {
-        if(microseconds == lastMicroseconds)
-            return;
-        lastMicroseconds = microseconds;
-        
-        const unsigned long cycles = F_CPU / 1000000 * microseconds;    // cycles corresponds to how many clock ticks per microsecond times number of microseconds we want
-        timer->CTRLA.bit.PRESCALER = 0;
-        if(cycles < timer_resolution) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV1_Val);
-            pwmPeriod = cycles;
-        } else
-        if(cycles < timer_resolution * 2) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV2_Val);
-            pwmPeriod = cycles / 2;
-        } else
-        if(cycles < timer_resolution * 4) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV4_Val);
-            pwmPeriod = cycles / 4;
-        } else
-        if(cycles < timer_resolution * 8) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV8_Val);
-            pwmPeriod = cycles / 8;
-        } else
-        if(cycles < timer_resolution * 16) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV16_Val);
-            pwmPeriod = cycles / 16;
-        } else
-        if(cycles < timer_resolution * 64) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV64_Val);
-            pwmPeriod = cycles / 64;
-        } else
-        if(cycles < timer_resolution * 1024) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV1024_Val);
-            pwmPeriod = cycles / 1024;
-        }
-        timer->PER.reg = pwmPeriod;
-        while (timer->SYNCBUSY.bit.PER);
-    }
-    void start() {
-        timer->CTRLA.bit.ENABLE = 1;                         // Turn on the output
-        while (timer->SYNCBUSY.bit.ENABLE);                  // Wait for synchronization
-    }
-    void stop() {
-        timer->CTRLA.bit.ENABLE = 0;                         // Turn on the output
-        while (timer->SYNCBUSY.bit.ENABLE);                  // Wait for synchronization
-    }
-
-    void attachInterrupt(void (*isr)()) {
-        isrCallback = isr;                                  // Store the interrupt callback function
-        timer->INTENSET.reg = TCC_INTENSET_OVF;              // Set the interrupt to occur on overflow
-
-        if(timer == TCC0) {
-             NVIC_EnableIRQ((IRQn_Type) TCC0_IRQn);              // Enable the interrupt (clock is still off)
-        }  
-        else if(timer == TCC1) {
-             NVIC_EnableIRQ((IRQn_Type) TCC1_IRQn);              // Enable the interrupt (clock is still off)
-        }  
-        else if(timer == TCC2) {
-             NVIC_EnableIRQ((IRQn_Type) TCC2_IRQn);              // Enable the interrupt (clock is still off)
-        }  
-    }
-    
-    void detachInterrupt() {
-        if(timer == TCC0) {
-             NVIC_DisableIRQ((IRQn_Type) TCC0_IRQn);              // Disable the interrupt 
-        }  
-        else if(timer == TCC1) {
-             NVIC_DisableIRQ((IRQn_Type) TCC1_IRQn);              // Disable the interrupt 
-        }  
-        else if(timer == TCC2) {
-             NVIC_DisableIRQ((IRQn_Type) TCC2_IRQn);              // Disable the interrupt 
-        }   
-    }
-};
-
-extern Timer TimerA;
-extern Timer TimerB;
-extern Timer TimerC;
-
-
-
-#endif // ATSAMC21Timer_h

ATSAMD21G/Timer.h

@@ -1,144 +0,0 @@
-#ifndef ATSAMD21GTimer_h
-#define ATSAMD21GTimer_h
-
-#include "../VirtualTimer.h"
-#include <Arduino.h>
-
-class Timer : public VirtualTimer
-{
-private:
-    int pwmPeriod;
-    unsigned long timer_resolution;
-    unsigned long lastMicroseconds;
-public:
-    void (*isrCallback)();
-    Tcc* timer;
-
-    Timer(Tcc* timer) {
-        this->timer = timer;
-        if(timer == TCC0 || timer == TCC1) {
-            timer_resolution = 16777216;
-        } else {
-            timer_resolution = 65536;
-        }
-        lastMicroseconds = 0;
-    }
-
-    void initialize() {
-        if(timer == TCC0 || timer == TCC1) {
-            REG_GCLK_GENDIV =   GCLK_GENDIV_DIV(1) |            // Divide 48MHz by 1
-                                GCLK_GENDIV_ID(4);              // Apply to GCLK4
-            while (GCLK->STATUS.bit.SYNCBUSY);                  // Wait for synchronization
-                
-            REG_GCLK_GENCTRL =  GCLK_GENCTRL_GENEN |            // Enable GCLK
-                                GCLK_GENCTRL_SRC_DFLL48M |      // Set the 48MHz clock source
-                                GCLK_GENCTRL_ID(4);             // Select GCLK4
-            while (GCLK->STATUS.bit.SYNCBUSY);                  // Wait for synchronization
-            
-            REG_GCLK_CLKCTRL =  GCLK_CLKCTRL_CLKEN |            // Enable generic clock
-                                4 << GCLK_CLKCTRL_GEN_Pos |     // Apply to GCLK4
-                                GCLK_CLKCTRL_ID_TCC0_TCC1;      // Feed GCLK to TCC0/1
-            while (GCLK->STATUS.bit.SYNCBUSY);                  // Wait for synchronization
-        } 
-        else if (timer == TCC2) {
-            REG_GCLK_GENDIV =   GCLK_GENDIV_DIV(1) |            // Divide 48MHz by 1
-                                GCLK_GENDIV_ID(5);              // Apply to GCLK4
-            while (GCLK->STATUS.bit.SYNCBUSY);                  // Wait for synchronization
-                
-            REG_GCLK_GENCTRL =  GCLK_GENCTRL_GENEN |            // Enable GCLK
-                                GCLK_GENCTRL_SRC_DFLL48M |      // Set the 48MHz clock source
-                                GCLK_GENCTRL_ID(5);             // Select GCLK4
-            while (GCLK->STATUS.bit.SYNCBUSY);                  // Wait for synchronization
-            
-            REG_GCLK_CLKCTRL =  GCLK_CLKCTRL_CLKEN |            // Enable generic clock
-                                5 << GCLK_CLKCTRL_GEN_Pos |     // Apply to GCLK4
-                                GCLK_CLKCTRL_ID_TCC2_TC3;      // Feed GCLK to TCC0/1
-            while (GCLK->STATUS.bit.SYNCBUSY);                  // Wait for synchronization
-        }
-        
-        
-        timer->WAVE.reg = TCC_WAVE_WAVEGEN_NPWM;             // Select NPWM as waveform
-        while (timer->SYNCBUSY.bit.WAVE);                    // Wait for synchronization
-
-    }
-    void setPeriod(unsigned long microseconds) {
-        if(microseconds == lastMicroseconds)
-            return;
-        lastMicroseconds = microseconds;
-        
-        const unsigned long cycles = F_CPU / 1000000 * microseconds;    // cycles corresponds to how many clock ticks per microsecond times number of microseconds we want
-        if(cycles < timer_resolution) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV1_Val);
-            pwmPeriod = cycles;
-        } else
-        if(cycles < timer_resolution * 2) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV2_Val);
-            pwmPeriod = cycles / 2;
-        } else
-        if(cycles < timer_resolution * 4) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV4_Val);
-            pwmPeriod = cycles / 4;
-        } else
-        if(cycles < timer_resolution * 8) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV8_Val);
-            pwmPeriod = cycles / 8;
-        } else
-        if(cycles < timer_resolution * 16) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV16_Val);
-            pwmPeriod = cycles / 16;
-        } else
-        if(cycles < timer_resolution * 64) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV64_Val);
-            pwmPeriod = cycles / 64;
-        } else
-        if(cycles < timer_resolution * 1024) {
-            timer->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV1024_Val);
-            pwmPeriod = cycles / 1024;
-        }
-        timer->PER.reg = pwmPeriod;
-        while (timer->SYNCBUSY.bit.PER);
-    }
-    void start() {
-        timer->CTRLA.bit.ENABLE = 1;                         // Turn on the output
-        while (timer->SYNCBUSY.bit.ENABLE);                  // Wait for synchronization
-    }
-    void stop() {
-        timer->CTRLA.bit.ENABLE = 0;                         // Turn on the output
-        while (timer->SYNCBUSY.bit.ENABLE);                  // Wait for synchronization
-    }
-
-    void attachInterrupt(void (*isr)()) {
-        isrCallback = isr;                                  // Store the interrupt callback function
-        timer->INTENSET.reg = TCC_INTENSET_OVF;              // Set the interrupt to occur on overflow
-
-        if(timer == TCC0) {
-             NVIC_EnableIRQ((IRQn_Type) TCC0_IRQn);              // Enable the interrupt (clock is still off)
-        }  
-        else if(timer == TCC1) {
-             NVIC_EnableIRQ((IRQn_Type) TCC1_IRQn);              // Enable the interrupt (clock is still off)
-        }  
-        else if(timer == TCC2) {
-             NVIC_EnableIRQ((IRQn_Type) TCC2_IRQn);              // Enable the interrupt (clock is still off)
-        }  
-    }
-    
-    void detachInterrupt() {
-        if(timer == TCC0) {
-             NVIC_DisableIRQ((IRQn_Type) TCC0_IRQn);              // Disable the interrupt 
-        }  
-        else if(timer == TCC1) {
-             NVIC_DisableIRQ((IRQn_Type) TCC1_IRQn);              // Disable the interrupt 
-        }  
-        else if(timer == TCC2) {
-             NVIC_DisableIRQ((IRQn_Type) TCC2_IRQn);              // Disable the interrupt 
-        }   
-    }
-};
-
-extern Timer TimerA;
-extern Timer TimerB;
-extern Timer TimerC;
-
-
-
-#endif

AnalogReadFast.h

@@ -1,112 +0,0 @@
-/*
- *  AnalogReadFast.h
- * 
- *  Copyright (C) 2016  Albert van Dalen http://www.avdweb.nl
- * 
- *  This file is part of CommandStation.
- *
- *  CommandStation is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation, either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  CommandStation is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-#ifndef COMMANDSTATION_DCC_ANALOGREADFAST_H_
-#define COMMANDSTATION_DCC_ANALOGREADFAST_H_
-
-#include <Arduino.h>
-
-int inline analogReadFast(uint8_t ADCpin);
-
-#if defined(ARDUINO_ARCH_SAMD) 
-int inline analogReadFast(uint8_t ADCpin)
-{ ADC->CTRLA.bit.ENABLE = 0;              // disable ADC
-  while( ADC->STATUS.bit.SYNCBUSY == 1 ); // wait for synchronization
-
-  int CTRLBoriginal = ADC->CTRLB.reg;
-  int AVGCTRLoriginal = ADC->AVGCTRL.reg;
-  int SAMPCTRLoriginal = ADC->SAMPCTRL.reg;
-  
-  ADC->CTRLB.reg &= 0b1111100011111111;          // mask PRESCALER bits
-  ADC->CTRLB.reg |= ADC_CTRLB_PRESCALER_DIV64;   // divide Clock by 64
-  ADC->AVGCTRL.reg = ADC_AVGCTRL_SAMPLENUM_1 |   // take 1 sample 
-                     ADC_AVGCTRL_ADJRES(0x00ul); // adjusting result by 0
-  ADC->SAMPCTRL.reg = 0x00;                      // sampling Time Length = 0
-
-  ADC->CTRLA.bit.ENABLE = 1;                     // enable ADC
-  while(ADC->STATUS.bit.SYNCBUSY == 1);          // wait for synchronization
-
-  int adc = analogRead(ADCpin); 
-  
-  ADC->CTRLB.reg = CTRLBoriginal;
-  ADC->AVGCTRL.reg = AVGCTRLoriginal;
-  ADC->SAMPCTRL.reg = SAMPCTRLoriginal;
-   
-  return adc;
-}
-
-#elif defined(ARDUINO_ARCH_SAMC) 
-
-int inline analogReadFast(uint8_t ADCpin)
-{ 
-  Adc* ADC;
-  if ( (g_APinDescription[ADCpin].ulPeripheralAttribute & PER_ATTR_ADC_MASK) == PER_ATTR_ADC_STD ) {
-    ADC = ADC0;
-  } else {
-    ADC = ADC1;
-  }
-  
-  ADC->CTRLA.bit.ENABLE = 0;              // disable ADC
-  while( ADC->SYNCBUSY.bit.ENABLE == 1 ); // wait for synchronization
-
-  int CTRLBoriginal = ADC->CTRLB.reg;
-  int AVGCTRLoriginal = ADC->AVGCTRL.reg;
-  int SAMPCTRLoriginal = ADC->SAMPCTRL.reg;
-  
-  ADC->CTRLB.reg &= 0b1111100011111111;          // mask PRESCALER bits
-  ADC->CTRLB.reg |= ADC_CTRLB_PRESCALER_DIV64;   // divide Clock by 64
-  ADC->AVGCTRL.reg = ADC_AVGCTRL_SAMPLENUM_1 |   // take 1 sample 
-                     ADC_AVGCTRL_ADJRES(0x00ul); // adjusting result by 0
-  ADC->SAMPCTRL.reg = 0x00;                      // sampling Time Length = 0
-
-  ADC->CTRLA.bit.ENABLE = 1;                     // enable ADC
-  while(ADC->SYNCBUSY.bit.ENABLE == 1);          // wait for synchronization
-
-  int adc = analogRead(ADCpin); 
-  
-  ADC->CTRLB.reg = CTRLBoriginal;
-  ADC->AVGCTRL.reg = AVGCTRLoriginal;
-  ADC->SAMPCTRL.reg = SAMPCTRLoriginal;
-   
-  return adc;
-}
-
-#elif defined(ARDUINO_AVR_UNO_WIFI_REV2) || defined(ARDUINO_AVR_NANO_EVERY)
-
-int inline analogReadFast(uint8_t ADCpin) 
-{ byte ADC0CTRLCoriginal = ADC0.CTRLC; 
-  ADC0.CTRLC = (ADC0CTRLCoriginal & 0b00110000) + 0b01000011; 
-  int adc = analogRead(ADCpin);  
-  ADC0.CTRLC = ADC0CTRLCoriginal;
-  return adc;
-}
-
-#else
-
-int inline analogReadFast(uint8_t ADCpin) 
-{ byte ADCSRAoriginal = ADCSRA; 
-  ADCSRA = (ADCSRA & B11111000) | 4; 
-  int adc = analogRead(ADCpin);  
-  ADCSRA = ADCSRAoriginal;
-  return adc;
-}
-#endif
-#endif  // COMMANDSTATION_DCC_ANALOGREADFAST_H_

ArduinoTimers.h

@@ -1,24 +0,0 @@
-// This file is copied from https://github.com/davidcutting42/ArduinoTimers
-// All Credit and copyright David Cutting
-// The files included below come from the same source.
-// This library had been included with the DCC code to avoid issues with
-// library management for inexperienced users. "It just works (TM)"
- 
-#ifndef ArduinoTimers_h
-#define ArduinoTimers_h
-
-#if defined(SAMC21)
-    #include "ATSAMC21G/Timer.h"
-#elif defined(ARDUINO_SAMD_ZERO)
-    #include "ATSAMD21G/Timer.h"
-#elif defined(ARDUINO_AVR_MEGA) || defined(ARDUINO_AVR_MEGA2560)
-    #include "ATMEGA2560/Timer.h"
-#elif defined(ARDUINO_AVR_UNO)
-    #include "ATMEGA328/Timer.h"
-#elif defined(ARDUINO_ARCH_MEGAAVR)
-    #include "ATMEGA4809/Timer.h"
-#else
-    #error "Cannot compile - ArduinoTimers library does not support your board, or you are missing compatible build flags."
-#endif
-
-#endif

CONTRIBUTING.md

@@ -0,0 +1,62 @@
+# Contributing
+
+Thanks for considering contributing to our project. Here is a guide for how to get started and and a list of our conventions. We will also walk you through the Github command line and Desktop commands necessary to download the code, make changes, and get it included in a next version of the sofware.
+
+Before contributing to this repository, please first discuss the change you wish to make via issue, or any other method with the owners of this repository before making a change. 
+
+Find us on our website at https://dcc-ex.com, on our Discord https://discord.gg/y2sB4Fp or on Trainboard: https://www.trainboard.com/highball/index.php?threads/dcc-update-project-2020.130071/
+
+# Development Environment
+
+We recommend using PlatformIO IDE for VSCode. If you haven't yet used it, it is an easy to learn and easy to use IDE that really shines for embedded development and the Arduino based hardware we use. For more information go to https://platformio.org/
+
+* Download and install the latest version of the Arduino IDE
+* Download and install the latest version of Visual Studio Code from Microsoft
+* Run VSCode and click on the "extensions" icon on the left. Install "PlatformIO IDE for VSCode" and the "Arduino Framework" support
+
+If you don't see C/C++ Installed in the list, install that too. We also recomment installing the Gitlens extension to make working with Git and GitHub even easier.
+
+You may ask if you can use the Arduino IDE, Visual Studio, or even a text editor and the answer is "of course" if you know what you are doing. Since you are just changing text files, you can use whatever you like as long as your commits and pull requests can be merged in GitHub. However, it will be much easier to follow our coding standards if you have an IDE that can automatically format things for you.
+
+# Coding Style Guidelines
+
+We have adopted the Google style guidlines. In particular please make sure to adhere to these standards:
+
+1. All header files should have #define guards to prevent multiple inclusion.
+2. Use Unix style line endings
+3. We indent using two spaces (soft tabs)
+4. Braces
+
+For more information just check our code or read https://google.github.io/styleguide/cppguide.html#C++_Version
+
+## Using the Repository
+
+1. Clone the repository on your local machine
+2. Create a working branch using the format "username-featurename" ex: "git branch -b frightrisk-turnouts"
+3. Commit offen, ex: "git add ." and then "git commit -m "description of your changes"
+4. Push your changes to our repository "git push"
+5. When you are ready, issue a pull request for your changes to be merged into the main branch
+
+## Pull Request Process
+
+1. Ensure any install or build dependencies are removed before the end of the layer when doing a build.
+
+## Code of Conduct
+
+Be Nice
+
+### Enforcement
+
+Contributors who do not follow the be nice rule in good faith may face temporary or permanent repercussions as determined by other members of the project's leadership.
+
+## How Can I Contribute?
+
+The DCC-EX Team has several projects and sub teams where you can help donate your epertise. See the sections below for the project or projects you are interested in.
+
+### Development
+### Documentation
+### WebThrottle-EX
+### Web Support
+### Organization/Coordination
+
+Links to external documentation goes here XXX

CommandDistributor.cpp

@@ -25,7 +25,7 @@ DCCEXParser * CommandDistributor::parser=0;
 void  CommandDistributor::parse(byte clientId,byte * buffer, RingStream * streamer) {
  if (buffer[0] == '<')  {
     if (!parser) parser = new DCCEXParser();
-    parser->parse(streamer, buffer, true); // tell JMRI parser that ACKS are blocking because we can't handle the async
+    parser->parse(streamer, buffer, streamer); 
   }
   else WiThrottle::getThrottle(clientId)->parse(streamer, buffer);
 }

CommandStation-EX.ino

@@ -1,15 +1,49 @@
 ////////////////////////////////////////////////////////////////////////////////////
-//  © 2020, Chris Harlow. All rights reserved.
+//  DCC-EX CommandStation-EX   Please see https://DCC-EX.com 
 //
-//  This file is a demonstattion of setting up a DCC-EX
-// Command station with optional support for direct connection of WiThrottle devices
-// such as "Engine Driver". If you contriol your layout through JMRI
-// then DON'T connect throttles to this wifi, connect them to JMRI.
+// This file is the main sketch for the Command Station.
+// 
+// CONFIGURATION: 
+// Configuration is normally performed by editing a file called config.h.
+// This file is NOT shipped with the code so that if you pull a later version
+// of the code, your configuration will not be overwritten.
 //
-//  THE WIFI FEATURE IS NOT SUPPORTED ON ARDUINO DEVICES WITH ONLY 2KB RAM.
+// If you used the automatic installer program, config.h will have been created automatically.
+// 
+// To obtain a starting copy of config.h please copy the file config.example.h which is 
+// shipped with the code and may be updated as new features are added. 
+// 
+// If config.h is not found, config.example.h will be used with all defaults.
 ////////////////////////////////////////////////////////////////////////////////////
 
-#include "config.h"
+#if __has_include ( "config.h")
+  #include "config.h"
+#else
+  #warning config.h not found. Using defaults from config.example.h 
+  #include "config.example.h"
+#endif
+
+
+/*
+ *  © 2020,2021 Chris Harlow, Harald Barth, David Cutting, 
+ *  Fred Decker, Gregor Baues, Anthony W - Dayton  All rights reserved.
+ *  
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
 #include "DCCEX.h"
 
 // Create a serial command parser for the USB connection, 
@@ -24,20 +58,28 @@ void setup()
   // Responsibility 1: Start the usb connection for diagnostics
   // This is normally Serial but uses SerialUSB on a SAMD processor
   Serial.begin(115200);
-  DIAG(F("DCC++ EX v%S"),F(VERSION));
-   
+#ifdef ESP_DEBUG
+  Serial.setDebugOutput(true);
+#endif
+
+  DIAG(F("License GPLv3 fsf.org (c) dcc-ex.com"));
+
   CONDITIONAL_LCD_START {
-    // This block is ignored if LCD not in use 
+    // This block is still executed for DIAGS if LCD not in use 
     LCD(0,F("DCC++ EX v%S"),F(VERSION));
-    LCD(1,F("Starting")); 
+    LCD(1,F("Lic GPLv3")); 
     }   
 
-//  Start the WiFi interface on a MEGA, Uno cannot currently handle WiFi
-
+  // Responsibility 2: Start all the communications before the DCC engine
+  // Start the WiFi interface on a MEGA, Uno cannot currently handle WiFi
+  // Start Ethernet if it exists
 #if WIFI_ON
-  WifiInterface::setup(WIFI_SERIAL_LINK_SPEED, F(WIFI_SSID), F(WIFI_PASSWORD), F(WIFI_HOSTNAME), IP_PORT);
+#ifndef ESP_FAMILY
+  WifiInterface::setup(WIFI_SERIAL_LINK_SPEED, F(WIFI_SSID), F(WIFI_PASSWORD), F(WIFI_HOSTNAME), IP_PORT, WIFI_CHANNEL);
+#else
+  WifiESP::setup(WIFI_SSID, WIFI_PASSWORD, WIFI_HOSTNAME, IP_PORT, WIFI_CHANNEL);
+#endif
 #endif // WIFI_ON
-
 #if ETHERNET_ON
   EthernetInterface::setup();
 #endif // ETHERNET_ON
@@ -46,14 +88,27 @@ void setup()
   // Note: this provides DCC with two motor drivers, main and prog, which handle the motor shield(s)
   // Standard supported devices have pre-configured macros but custome hardware installations require
   //  detailed pin mappings and may also require modified subclasses of the MotorDriver to implement specialist logic.
-
   // STANDARD_MOTOR_SHIELD, POLOLU_MOTOR_SHIELD, FIREBOX_MK1, FIREBOX_MK1S are pre defined in MotorShields.h
+  DCC::begin(MOTOR_SHIELD_TYPE);
+         
+  // Start RMFT (ignored if no automnation)
+  RMFT::begin();
+  
 
-  // Optionally a Timer number (1..4) may be passed to DCC::begin to override the default Timer1 used for the
-  // waveform generation.  e.g.  DCC::begin(STANDARD_MOTOR_SHIELD,2); to use timer 2
+  // Invoke any DCC++EX commands in the form "SETUP("xxxx");"" found in optional file mySetup.h.  
+  //  This can be used to create turnouts, outputs, sensors etc. through the normal text commands.
+  #if __has_include ( "mySetup.h")
+        #define SETUP(cmd) serialParser.parse(F(cmd))  
+        #include "mySetup.h"
+        #undef SETUP
+       #endif
 
-  DCC::begin(MOTOR_SHIELD_TYPE); 
-  LCD(1,F("Ready")); 
+  #if defined(LCN_SERIAL)
+      LCN_SERIAL.begin(115200); 
+      LCN::init(LCN_SERIAL);
+  #endif
+
+  LCD(3,F("Ready")); 
 }
 
 void loop()
@@ -63,29 +118,42 @@ void loop()
   // Responsibility 1: Handle DCC background processes
   //                   (loco reminders and power checks)
   DCC::loop();
-
   // Responsibility 2: handle any incoming commands on USB connection
   serialParser.loop(Serial);
 
 // Responsibility 3: Optionally handle any incoming WiFi traffic
 #if WIFI_ON
+#ifndef ESP_FAMILY
   WifiInterface::loop();
 #endif
+#if defined(ARDUINO_ARCH_ESP8266) // on ESP32 own task
+  WifiESP::loop();
+#endif
+#endif //WIFI_ON
 #if ETHERNET_ON
   EthernetInterface::loop();
 #endif
 
-  LCDDisplay::loop();  // ignored if LCD not in use 
-  
-// Optionally report any decrease in memory (will automatically trigger on first call)
-#if ENABLE_FREE_MEM_WARNING
-  static int ramLowWatermark = 32767; // replaced on first loop 
+  RMFT::loop();  // ignored if no automation
 
-  int freeNow = freeMemory();
+  #if defined(LCN_SERIAL) 
+      LCN::loop();
+  #endif
+
+  LCDDisplay::loop();  // ignored if LCD not in use 
+
+  // Handle/update IO devices.
+  IODevice::loop();
+  
+  // Report any decrease in memory (will automatically trigger on first call)
+  static int ramLowWatermark = __INT_MAX__; // replaced on first loop 
+#ifdef ESP_FAMILY
+  updateMinimumFreeMemory(128);
+#endif
+  int freeNow = minimumFreeMemory();
   if (freeNow < ramLowWatermark)
   {
     ramLowWatermark = freeNow;
-    LCD(2,F("Free RAM=%5db"), ramLowWatermark);
+    LCD(3,F("Free RAM=%5db"), ramLowWatermark);
   }
-#endif
 }

DCC.cpp

@@ -17,12 +17,14 @@
  *  You should have received a copy of the GNU General Public License
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
+#include "DIAG.h"
 #include "DCC.h"
 #include "DCCWaveform.h"
-#include "DIAG.h"
 #include "EEStore.h"
 #include "GITHUB_SHA.h"
 #include "version.h"
+#include "FSH.h"
+#include "IODevice.h"
 
 // This module is responsible for converting API calls into
 // messages to be sent to the waveform generator.
@@ -43,17 +45,30 @@ const byte FN_GROUP_3=0x04;
 const byte FN_GROUP_4=0x08;         
 const byte FN_GROUP_5=0x10;         
 
-__FlashStringHelper* DCC::shieldName=NULL;
+FSH* DCC::shieldName=NULL;
+byte DCC::joinRelay=UNUSED_PIN;
+byte DCC::globalSpeedsteps=128;
 
-void DCC::begin(const __FlashStringHelper* motorShieldName, MotorDriver * mainDriver, MotorDriver* progDriver, byte timerNumber) {
-  shieldName=(__FlashStringHelper*)motorShieldName;
-  DIAG(F("<iDCC-EX V-%S / %S / %S G-%S>\n"), F(VERSION), F(ARDUINO_TYPE), shieldName, F(GITHUB_SHA));
+void DCC::begin(const FSH * motorShieldName, MotorDriver * mainDriver, MotorDriver* progDriver) {
+  shieldName=(FSH *)motorShieldName;
+  StringFormatter::send(Serial,F("<iDCC-EX V-%S / %S / %S G-%S>\n"), F(VERSION), F(ARDUINO_TYPE), shieldName, F(GITHUB_SHA));
+
+  // Initialise HAL layer before reading EEprom.
+  IODevice::begin();
 
   // Load stuff from EEprom
   (void)EEPROM; // tell compiler not to warn this is unused
   EEStore::init();
 
-  DCCWaveform::begin(mainDriver,progDriver, timerNumber); 
+  DCCWaveform::begin(mainDriver,progDriver); 
+}
+
+void DCC::setJoinRelayPin(byte joinRelayPin) {
+  joinRelay=joinRelayPin;
+  if (joinRelay!=UNUSED_PIN) {
+    pinMode(joinRelay,OUTPUT);
+    digitalWrite(joinRelay,LOW);  // LOW is relay disengaged
+  }
 }
 
 void DCC::setThrottle( uint16_t cab, uint8_t tSpeed, bool tDirection)  {
@@ -67,19 +82,45 @@ void DCC::setThrottle2( uint16_t cab, byte speedCode)  {
 
   uint8_t b[4];
   uint8_t nB = 0;
-  // DIAG(F("\nsetSpeedInternal %d %x"),cab,speedCode);
+  // DIAG(F("setSpeedInternal %d %x"),cab,speedCode);
   
   if (cab > 127)
     b[nB++] = highByte(cab) | 0xC0;    // convert train number into a two-byte address
   b[nB++] = lowByte(cab);
-  b[nB++] = SET_SPEED;                      // 128-step speed control byte
-  b[nB++] = speedCode; // for encoding see setThrottle
+
+  if (globalSpeedsteps <= 28) {
+
+    uint8_t speed128 = speedCode & 0x7F;
+    uint8_t speed28;
+    uint8_t code28;
+
+    if (speed128 == 0 || speed128 == 1) { // stop or emergency stop
+      code28 = speed128;
+    } else {
+      speed28= (speed128*10+36)/46;                 // convert 2-127 to 1-28
+/*
+      if (globalSpeedsteps <= 14)                   // Don't want to do 14 steps, to get F0 there is ugly
+        code28 = (speed28+3)/2 | (Value of F0);     // convert 1-28 to DCC 14 step speed code
+      else
+*/
+      code28 = (speed28+3)/2 | ( (speed28 & 1) ? 0 : 0b00010000 ); // convert 1-28 to DCC 28 step speed code
+    }
+    //        Construct command byte from:
+    //        command      speed    direction
+    b[nB++] = 0b01000000 | code28 | ((speedCode & 0x80) ? 0b00100000 : 0);
+
+  } else { // 128 speedsteps
+
+    b[nB++] = SET_SPEED;                      // 128-step speed control byte
+    b[nB++] = speedCode; // for encoding see setThrottle
+
+  }
 
   DCCWaveform::mainTrack.schedulePacket(b, nB, 0);
 }
 
 void DCC::setFunctionInternal(int cab, byte byte1, byte byte2) {
-  // DIAG(F("\nsetFunctionInternal %d %x %x"),cab,byte1,byte2);
+  // DIAG(F("setFunctionInternal %d %x %x"),cab,byte1,byte2);
   byte b[4];
   byte nB = 0;
 
@@ -89,7 +130,7 @@ void DCC::setFunctionInternal(int cab, byte byte1, byte byte2) {
   if (byte1!=0) b[nB++] = byte1;
   b[nB++] = byte2;
 
-  DCCWaveform::mainTrack.schedulePacket(b, nB, 3);     // send packet 3 times
+  DCCWaveform::mainTrack.schedulePacket(b, nB, 0);
 }
 
 uint8_t DCC::getThrottleSpeed(int cab) {
@@ -100,13 +141,34 @@ uint8_t DCC::getThrottleSpeed(int cab) {
 
 bool DCC::getThrottleDirection(int cab) {
   int reg=lookupSpeedTable(cab);
-  if (reg<0) return false ;
+  if (reg<0) return true;
   return (speedTable[reg].speedCode & 0x80) !=0;
 }
 
 // Set function to value on or off
-void DCC::setFn( int cab, byte functionNumber, bool on) {
-  if (cab<=0 || functionNumber>28) return;
+void DCC::setFn( int cab, int16_t functionNumber, bool on) {
+  if (cab<=0 ) return;
+  
+  if (functionNumber>28) { 
+    //non reminding advanced binary bit set 
+    byte b[5];
+    byte nB = 0;
+    if (cab > 127)
+      b[nB++] = highByte(cab) | 0xC0;    // convert train number into a two-byte address
+    b[nB++] = lowByte(cab);
+    if (functionNumber <= 127) {
+       b[nB++] = 0b11011101;   // Binary State Control Instruction short form  
+       b[nB++] = functionNumber | (on ? 0x80 : 0);
+    }
+    else  {
+       b[nB++] = 0b11000000;   // Binary State Control Instruction long form  
+       b[nB++] = (functionNumber & 0x7F) | (on ? 0x80 : 0);  // low order bits and state flag
+       b[nB++] = functionNumber >>7 ;  // high order bits
+    }
+    DCCWaveform::mainTrack.schedulePacket(b, nB, 4);
+    return;
+  }
+  
   int reg = lookupSpeedTable(cab);
   if (reg<0) return;  
 
@@ -125,7 +187,7 @@ void DCC::setFn( int cab, byte functionNumber, bool on) {
 // Change function according to how button was pressed,
 // typically in WiThrottle.
 // Returns new state or -1 if nothing was changed.
-int DCC::changeFn( int cab, byte functionNumber, bool pressed) {
+int DCC::changeFn( int cab, int16_t functionNumber, bool pressed) {
   int funcstate = -1;
   if (cab<=0 || functionNumber>28) return funcstate;
   int reg = lookupSpeedTable(cab);
@@ -147,15 +209,15 @@ int DCC::changeFn( int cab, byte functionNumber, bool pressed) {
   } else {
       // toggle function on press, ignore release
       if (pressed) {
-	  speedTable[reg].functions ^= funcmask;
+        speedTable[reg].functions ^= funcmask;
       }
-      funcstate = speedTable[reg].functions & funcmask;
+      funcstate = (speedTable[reg].functions & funcmask)? 1 : 0;
   }
   updateGroupflags(speedTable[reg].groupFlags, functionNumber);
   return funcstate;
 }
 
-int DCC::getFn( int cab, byte functionNumber) {
+int DCC::getFn( int cab, int16_t functionNumber) {
   if (cab<=0 || functionNumber>28) return -1;  // unknown
   int reg = lookupSpeedTable(cab);
   if (reg<0) return -1;  
@@ -166,7 +228,7 @@ int DCC::getFn( int cab, byte functionNumber) {
 
 // Set the group flag to say we have touched the particular group.
 // A group will be reminded only if it has been touched.  
-void DCC::updateGroupflags(byte & flags, int functionNumber) {
+void DCC::updateGroupflags(byte & flags, int16_t functionNumber) {
   byte groupMask;
   if (functionNumber<=4)       groupMask=FN_GROUP_1;
   else if (functionNumber<=8)  groupMask=FN_GROUP_2;
@@ -177,6 +239,9 @@ void DCC::updateGroupflags(byte & flags, int functionNumber) {
 }
 
 void DCC::setAccessory(int address, byte number, bool activate) {
+  #ifdef DIAG_IO
+  DIAG(F("DCC::setAccessory(%d,%d,%d)"), address, number, activate);
+  #endif
   // use masks to detect wrong values and do nothing
   if(address != (address & 511))
     return;
@@ -190,6 +255,10 @@ void DCC::setAccessory(int address, byte number, bool activate) {
   DCCWaveform::mainTrack.schedulePacket(b, 2, 4);      // Repeat the packet four times
 }
 
+//
+// writeCVByteMain: Write a byte with PoM on main. This writes
+// the 5 byte sized packet to implement this DCC function
+//
 void DCC::writeCVByteMain(int cab, int cv, byte bValue)  {
   byte b[5];
   byte nB = 0;
@@ -204,6 +273,10 @@ void DCC::writeCVByteMain(int cab, int cv, byte bValue)  {
   DCCWaveform::mainTrack.schedulePacket(b, nB, 4);
 }
 
+//
+// writeCVBitMain: Write a bit of a byte with PoM on main. This writes
+// the 5 byte sized packet to implement this DCC function
+//
 void DCC::writeCVBitMain(int cab, int cv, byte bNum, bool bValue)  {
   byte b[5];
   byte nB = 0;
@@ -222,69 +295,71 @@ void DCC::writeCVBitMain(int cab, int cv, byte bNum, bool bValue)  {
 }
 
 void DCC::setProgTrackSyncMain(bool on) {
+  if (joinRelay!=UNUSED_PIN) digitalWrite(joinRelay,on?HIGH:LOW);
   DCCWaveform::progTrackSyncMain=on;
 }
 void DCC::setProgTrackBoost(bool on) {
   DCCWaveform::progTrackBoosted=on;
 }
 
-__FlashStringHelper* DCC::getMotorShieldName() {
+FSH* DCC::getMotorShieldName() {
   return shieldName;
 }
   
-const ackOp PROGMEM WRITE_BIT0_PROG[] = {
+const ackOp FLASH WRITE_BIT0_PROG[] = {
      BASELINE,
      W0,WACK,
      V0, WACK,  // validate bit is 0 
      ITC1,      // if acked, callback(1)
-     FAIL  // callback (-1)
+     CALLFAIL  // callback (-1)
 };
-const ackOp PROGMEM WRITE_BIT1_PROG[] = {
+const ackOp FLASH WRITE_BIT1_PROG[] = {
      BASELINE,
      W1,WACK,
      V1, WACK,  // validate bit is 1 
      ITC1,      // if acked, callback(1)
-     FAIL  // callback (-1)
+     CALLFAIL  // callback (-1)
 };
 
-const ackOp PROGMEM VERIFY_BIT0_PROG[] = {
+const ackOp FLASH VERIFY_BIT0_PROG[] = {
      BASELINE,
      V0, WACK,  // validate bit is 0 
      ITC0,      // if acked, callback(0)
      V1, WACK,  // validate bit is 1
      ITC1,       
-     FAIL  // callback (-1)
+     CALLFAIL  // callback (-1)
 };
-const ackOp PROGMEM VERIFY_BIT1_PROG[] = {
+const ackOp FLASH VERIFY_BIT1_PROG[] = {
      BASELINE,
      V1, WACK,  // validate bit is 1 
      ITC1,      // if acked, callback(1)
      V0, WACK, 
      ITC0,
-     FAIL  // callback (-1)
+     CALLFAIL  // callback (-1)
 };
 
-const ackOp PROGMEM READ_BIT_PROG[] = {
+const ackOp FLASH READ_BIT_PROG[] = {
      BASELINE,
      V1, WACK,  // validate bit is 1 
      ITC1,      // if acked, callback(1)
      V0, WACK,  // validate bit is zero
      ITC0,      // if acked callback 0
-     FAIL       // bit not readable 
+     CALLFAIL       // bit not readable 
      };
      
-const ackOp PROGMEM WRITE_BYTE_PROG[] = {
+const ackOp FLASH WRITE_BYTE_PROG[] = {
       BASELINE,
-      WB,WACK,    // Write 
-      VB,WACK,     // validate byte 
-      ITC1,       // if ok callback (1)
-      FAIL        // callback (-1)
+      WB,WACK,ITC1,    // Write and callback(1) if ACK 
+      // handle decoders that dont ack a write 
+      VB,WACK,ITC1,    // validate byte and callback(1) if correct 
+      CALLFAIL        // callback (-1)
       };
       
-const ackOp PROGMEM VERIFY_BYTE_PROG[] = {
+const ackOp FLASH VERIFY_BYTE_PROG[] = {
       BASELINE,
+      BIV,         // ackManagerByte initial value
       VB,WACK,     // validate byte 
-      ITCB,       // if ok callback value
+      ITCB,       // if ok callback value	
       STARTMERGE,    //clear bit and byte values ready for merge pass
       // each bit is validated against 0 and the result inverted in MERGE
       // this is because there tend to be more zeros in cv values than ones.  
@@ -302,11 +377,11 @@ const ackOp PROGMEM VERIFY_BYTE_PROG[] = {
       V0, WACK, MERGE,
       V0, WACK, MERGE,
       V0, WACK, MERGE,
-      VB, WACK, ITCB,  // verify merged byte and return it if acked ok 
-      FAIL };
+      VB, WACK, ITCBV,  // verify merged byte and return it if acked ok - with retry report
+      CALLFAIL };
       
       
-const ackOp PROGMEM READ_CV_PROG[] = {
+const ackOp FLASH READ_CV_PROG[] = {
       BASELINE,
       STARTMERGE,    //clear bit and byte values ready for merge pass
       // each bit is validated against 0 and the result inverted in MERGE
@@ -326,15 +401,32 @@ const ackOp PROGMEM READ_CV_PROG[] = {
       V0, WACK, MERGE,
       V0, WACK, MERGE,
       VB, WACK, ITCB,  // verify merged byte and return it if acked ok 
-      FAIL };          // verification failed
+      CALLFAIL };          // verification failed
 
 
-const ackOp PROGMEM LOCO_ID_PROG[] = {
+const ackOp FLASH LOCO_ID_PROG[] = {
       BASELINE,
+      SETCV, (ackOp)19,     // CV 19 is consist setting
+      SETBYTE, (ackOp)0,    
+      VB, WACK, ITSKIP,     // ignore consist if cv19 is zero (no consist)
+      SETBYTE, (ackOp)128,
+      VB, WACK, ITSKIP,     // ignore consist if cv19 is 128 (no consist, direction bit set)
+      STARTMERGE,           // Setup to read cv 19
+      V0, WACK, MERGE,  
+      V0, WACK, MERGE,  
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      VB, WACK, ITCB7,  // return 7 bits only, No_ACK means CV19 not supported so ignore it
+      
+      SKIPTARGET,     // continue here if CV 19 is zero or fails all validation      
       SETCV,(ackOp)29,
       SETBIT,(ackOp)5,
       V0, WACK, ITSKIP,  // Skip to SKIPTARGET if bit 5 of CV29 is zero
-      V1, WACK, NAKFAIL, // fast fail if no loco on track
+      
       // Long locoid  
       SETCV, (ackOp)17,       // CV 17 is part of locoid
       STARTMERGE,
@@ -366,7 +458,7 @@ const ackOp PROGMEM LOCO_ID_PROG[] = {
       SKIPTARGET,
       SETCV, (ackOp)1,
       STARTMERGE,
-      V0, WACK, MERGE,  // read and merge bit 1 etc
+      SETBIT, (ackOp)6,  // skip over first bit as we know its a zero
       V0, WACK, MERGE,
       V0, WACK, MERGE,
       V0, WACK, MERGE,
@@ -375,64 +467,109 @@ const ackOp PROGMEM LOCO_ID_PROG[] = {
       V0, WACK, MERGE,
       V0, WACK, MERGE,
       VB, WACK, ITCB,  // verify merged byte and callback
-      FAIL
+      CALLFAIL
       };    
 
+const ackOp FLASH SHORT_LOCO_ID_PROG[] = {
+      BASELINE,
+      SETCV,(ackOp)19,
+      SETBYTE, (ackOp)0,
+      WB,WACK,     // ignore dedcoder without cv19 support
+      // Turn off long address flag
+      SETCV,(ackOp)29,
+      SETBIT,(ackOp)5,
+      W0,WACK,
+      V0,WACK,NAKFAIL,
+      SETCV, (ackOp)1,   
+      SETBYTEL,   // low byte of word 
+      WB,WACK,    // some decoders don't ACK writes
+      VB,WACK,ITCB,
+      CALLFAIL
+};    
 
-// On the following prog-track functions blocking defaults to false.
-// blocking=true forces the API to block, waiting for the response and invoke the callback BEFORE returning.
-// During that wait, other parts of the system will be unresponsive.
-// blocking =false means the callback will be called some time after the API returns (typically a few tenths of a second)
-//  but that would be very inconvenient in a Wifi situaltion where the stream becomes 
-//  unuavailable immediately after the API rerturns. 
+const ackOp FLASH LONG_LOCO_ID_PROG[] = {
+      BASELINE,
+      // Clear consist CV 19
+      SETCV,(ackOp)19,
+      SETBYTE, (ackOp)0,
+      WB,WACK,     // ignore decoder without cv19 support
+      // Turn on long address flag cv29 bit 5
+      SETCV,(ackOp)29,
+      SETBIT,(ackOp)5,
+      W1,WACK,
+      V1,WACK,NAKFAIL,
+      // Store high byte of address in cv 17
+      SETCV, (ackOp)17,
+      SETBYTEH,   // high byte of word 
+      WB,WACK,
+      VB,WACK,NAKFAIL,
+      // store 
+      SETCV, (ackOp)18,
+      SETBYTEL,   // low byte of word 
+      WB,WACK,
+      VB,WACK,ITC1,   // callback(1) means Ok
+      CALLFAIL
+};    
 
-void  DCC::writeCVByte(int cv, byte byteValue, ACK_CALLBACK callback, bool blocking)  {
-  ackManagerSetup(cv, byteValue,  WRITE_BYTE_PROG, callback, blocking);
+void  DCC::writeCVByte(int16_t cv, byte byteValue, ACK_CALLBACK callback)  {
+  ackManagerSetup(cv, byteValue,  WRITE_BYTE_PROG, callback);
 }
 
-
-void DCC::writeCVBit(int cv, byte bitNum, bool bitValue, ACK_CALLBACK callback, bool blocking)  {
+void DCC::writeCVBit(int16_t cv, byte bitNum, bool bitValue, ACK_CALLBACK callback)  {
   if (bitNum >= 8) callback(-1);
-  else ackManagerSetup(cv, bitNum, bitValue?WRITE_BIT1_PROG:WRITE_BIT0_PROG, callback, blocking);
+  else ackManagerSetup(cv, bitNum, bitValue?WRITE_BIT1_PROG:WRITE_BIT0_PROG, callback);
 }
 
-void  DCC::verifyCVByte(int cv, byte byteValue, ACK_CALLBACK callback, bool blocking)  {
-  ackManagerSetup(cv, byteValue,  VERIFY_BYTE_PROG, callback, blocking);
+void  DCC::verifyCVByte(int16_t cv, byte byteValue, ACK_CALLBACK callback)  {
+  ackManagerSetup(cv, byteValue,  VERIFY_BYTE_PROG, callback);
 }
 
-
-void DCC::verifyCVBit(int cv, byte bitNum, bool bitValue, ACK_CALLBACK callback, bool blocking)  {
+void DCC::verifyCVBit(int16_t cv, byte bitNum, bool bitValue, ACK_CALLBACK callback)  {
   if (bitNum >= 8) callback(-1);
-  else ackManagerSetup(cv, bitNum, bitValue?VERIFY_BIT1_PROG:VERIFY_BIT0_PROG, callback, blocking);
+  else ackManagerSetup(cv, bitNum, bitValue?VERIFY_BIT1_PROG:VERIFY_BIT0_PROG, callback);
 }
 
 
-void DCC::readCVBit(int cv, byte bitNum, ACK_CALLBACK callback, bool blocking)  {
+void DCC::readCVBit(int16_t cv, byte bitNum, ACK_CALLBACK callback)  {
   if (bitNum >= 8) callback(-1);
-  else ackManagerSetup(cv, bitNum,READ_BIT_PROG, callback, blocking);
+  else ackManagerSetup(cv, bitNum,READ_BIT_PROG, callback);
 }
 
-void DCC::readCV(int cv, ACK_CALLBACK callback, bool blocking)  {
-  ackManagerSetup(cv, 0,READ_CV_PROG, callback, blocking);
+void DCC::readCV(int16_t cv, ACK_CALLBACK callback)  {
+  ackManagerSetup(cv, 0,READ_CV_PROG, callback);
 }
 
-void DCC::getLocoId(ACK_CALLBACK callback, bool blocking) {
-  ackManagerSetup(0,0, LOCO_ID_PROG, callback, blocking);
+void DCC::getLocoId(ACK_CALLBACK callback) {
+  ackManagerSetup(0,0, LOCO_ID_PROG, callback);
 }
 
-void DCC::forgetLoco(int cab) {  // removes any speed reminders for this loco  
+void DCC::setLocoId(int id,ACK_CALLBACK callback) {
+  if (id<1 || id>10239) { //0x27FF according to standard
+    callback(-1);
+    return;
+  }
+  if (id<=127)
+      ackManagerSetup(id, SHORT_LOCO_ID_PROG, callback);
+  else
+      ackManagerSetup(id | 0xc000,LONG_LOCO_ID_PROG, callback);
+}
+
+void DCC::forgetLoco(int cab) {  // removes any speed reminders for this loco
+  setThrottle2(cab,1); // ESTOP this loco if still on track  
   int reg=lookupSpeedTable(cab);
   if (reg>=0) speedTable[reg].loco=0;
+  setThrottle2(cab,1); // ESTOP if this loco still on track
 }
 void DCC::forgetAllLocos() {  // removes all speed reminders
-  for (int i=0;i<MAX_LOCOS;i++) speedTable[i].loco=0;  
+  setThrottle2(0,1); // ESTOP all locos still on track      
+  for (int i=0;i<MAX_LOCOS;i++) speedTable[i].loco=0;
 }
 
 byte DCC::loopStatus=0;  
 
 void DCC::loop()  {
-  DCCWaveform::loop(); // power overload checks
-  ackManagerLoop(false);    // maintain prog track ack manager
+  DCCWaveform::loop(ackManagerProg!=NULL); // power overload checks
+  ackManagerLoop();    // maintain prog track ack manager
   issueReminders();
 }
 
@@ -460,7 +597,7 @@ bool DCC::issueReminder(int reg) {
   
   switch (loopStatus) {
         case 0:
-      //   DIAG(F("\nReminder %d speed %d"),loco,speedTable[reg].speedCode);
+      //   DIAG(F("Reminder %d speed %d"),loco,speedTable[reg].speedCode);
          setThrottle2(loco, speedTable[reg].speedCode);
          break;
        case 1: // remind function group 1 (F0-F4)
@@ -518,7 +655,7 @@ int DCC::lookupSpeedTable(int locoId) {
   }
   if (reg == MAX_LOCOS) reg = firstEmpty;
   if (reg >= MAX_LOCOS) {
-    DIAG(F("\nToo many locos\n"));
+    DIAG(F("Too many locos"));
     return -1;
   }
   if (reg==firstEmpty){
@@ -550,81 +687,109 @@ int DCC::nextLoco = 0;
 
 //ACK MANAGER
 ackOp  const *  DCC::ackManagerProg;
+ackOp  const *  DCC::ackManagerProgStart;
 byte   DCC::ackManagerByte;
+byte   DCC::ackManagerByteVerify;
 byte   DCC::ackManagerStash;
-int   DCC::ackManagerCv;
+int    DCC::ackManagerWord;
+byte   DCC::ackManagerRetry;
+byte   DCC::ackRetry = 2;
+int16_t  DCC::ackRetrySum;
+int16_t  DCC::ackRetryPSum;
+int    DCC::ackManagerCv;
 byte   DCC::ackManagerBitNum;
 bool   DCC::ackReceived;
+bool   DCC::ackManagerRejoin;
+
+CALLBACK_STATE DCC::callbackState=READY;
 
 ACK_CALLBACK DCC::ackManagerCallback;
 
-void  DCC::ackManagerSetup(int cv, byte byteValueOrBitnum, ackOp const program[], ACK_CALLBACK callback, bool blocking) {
+void  DCC::ackManagerSetup(int cv, byte byteValueOrBitnum, ackOp const program[], ACK_CALLBACK callback) {
+  if (!DCCWaveform::progTrack.canMeasureCurrent()) {
+    callback(-2);
+    return;
+  }
+
+  ackManagerRejoin=DCCWaveform::progTrackSyncMain;     
+  if (ackManagerRejoin ) {
+        // Change from JOIN must zero resets packet.
+        setProgTrackSyncMain(false);
+        DCCWaveform::progTrack.sentResetsSincePacket = 0;      
+      }
+      
+   DCCWaveform::progTrack.autoPowerOff=false;           
+   if (DCCWaveform::progTrack.getPowerMode() == POWERMODE::OFF) {
+        DCCWaveform::progTrack.autoPowerOff=true;  // power off afterwards           
+        if (Diag::ACK) DIAG(F("Auto Prog power on"));
+        DCCWaveform::progTrack.setPowerMode(POWERMODE::ON);
+        DCCWaveform::progTrack.sentResetsSincePacket = 0;      
+    }
+
   ackManagerCv = cv;
   ackManagerProg = program;
+  ackManagerProgStart = program;
+  ackManagerRetry = ackRetry;
   ackManagerByte = byteValueOrBitnum;
+  ackManagerByteVerify = byteValueOrBitnum;
   ackManagerBitNum=byteValueOrBitnum;
   ackManagerCallback = callback;
-  if (blocking) ackManagerLoop(blocking);
 }
 
+void  DCC::ackManagerSetup(int wordval, ackOp const program[], ACK_CALLBACK callback) {
+  ackManagerWord=wordval;
+  ackManagerSetup(0, 0, program, callback);
+  }
+
 const byte RESET_MIN=8;  // tuning of reset counter before sending message
 
 // checkRessets return true if the caller should yield back to loop and try later.
-bool DCC::checkResets(bool blocking, uint8_t numResets) {
-  if (blocking) {
-    // must block waiting for restest to be issued
-    while(DCCWaveform::progTrack.sentResetsSincePacket < numResets);
-    return false; // caller need not yield
-  }
+bool DCC::checkResets(uint8_t numResets) {
   return DCCWaveform::progTrack.sentResetsSincePacket < numResets;
 }
 
-void DCC::ackManagerLoop(bool blocking) {
+void DCC::ackManagerLoop() {
   while (ackManagerProg) {
-    byte opcode=pgm_read_byte_near(ackManagerProg);
+    byte opcode=GETFLASH(ackManagerProg);
     
     // breaks from this switch will step to next prog entry
     // returns from this switch will stay on same entry
     // (typically waiting for a reset counter or ACK waiting, or when all finished.)
-    // if blocking then we must ONLY return AFTER callback issued       
     switch (opcode) {
       case BASELINE:
-	  if (DCCWaveform::progTrack.getPowerMode() == POWERMODE::OFF) {
-        if (Diag::ACK) DIAG(F("\nAuto Prog power on"));
-        DCCWaveform::progTrack.setPowerMode(POWERMODE::ON);
-        DCCWaveform::progTrack.sentResetsSincePacket = 0;
-	      DCCWaveform::progTrack.autoPowerOff=true;
-	      if (!blocking) return;
-	  }
-	  if (checkResets(blocking, DCCWaveform::progTrack.autoPowerOff ? 20 : 3)) return;
+          if (DCCWaveform::progTrack.getPowerMode()==POWERMODE::OVERLOAD) return;
+      	  if (checkResets(DCCWaveform::progTrack.autoPowerOff || ackManagerRejoin  ? 20 : 3)) return;
           DCCWaveform::progTrack.setAckBaseline();
+          callbackState=READY;
           break;   
       case W0:    // write 0 bit 
       case W1:    // write 1 bit 
             {
-	      if (checkResets(blocking, RESET_MIN)) return;
-              if (Diag::ACK) DIAG(F("\nW%d cv=%d bit=%d"),opcode==W1, ackManagerCv,ackManagerBitNum); 
+	      if (checkResets(RESET_MIN)) return;
+              if (Diag::ACK) DIAG(F("W%d cv=%d bit=%d"),opcode==W1, ackManagerCv,ackManagerBitNum); 
               byte instruction = WRITE_BIT | (opcode==W1 ? BIT_ON : BIT_OFF) | ackManagerBitNum;
               byte message[] = {cv1(BIT_MANIPULATE, ackManagerCv), cv2(ackManagerCv), instruction };
               DCCWaveform::progTrack.schedulePacket(message, sizeof(message), PROG_REPEATS);
               DCCWaveform::progTrack.setAckPending(); 
+             callbackState=AFTER_WRITE;
          }
             break; 
       
       case WB:   // write byte 
             {
-	      if (checkResets(blocking, RESET_MIN)) return;
-              if (Diag::ACK) DIAG(F("\nWB cv=%d value=%d"),ackManagerCv,ackManagerByte);
+	      if (checkResets( RESET_MIN)) return;
+              if (Diag::ACK) DIAG(F("WB cv=%d value=%d"),ackManagerCv,ackManagerByte);
               byte message[] = {cv1(WRITE_BYTE, ackManagerCv), cv2(ackManagerCv), ackManagerByte};
               DCCWaveform::progTrack.schedulePacket(message, sizeof(message), PROG_REPEATS);
               DCCWaveform::progTrack.setAckPending(); 
+              callbackState=AFTER_WRITE;
             }
             break;
       
       case   VB:     // Issue validate Byte packet
         {
-	  if (checkResets(blocking, RESET_MIN)) return; 
-          if (Diag::ACK) DIAG(F("\nVB cv=%d value=%d"),ackManagerCv,ackManagerByte);
+	  if (checkResets( RESET_MIN)) return; 
+          if (Diag::ACK) DIAG(F("VB cv=%d value=%d"),ackManagerCv,ackManagerByte);
           byte message[] = { cv1(VERIFY_BYTE, ackManagerCv), cv2(ackManagerCv), ackManagerByte};
           DCCWaveform::progTrack.schedulePacket(message, sizeof(message), PROG_REPEATS);
           DCCWaveform::progTrack.setAckPending(); 
@@ -634,8 +799,8 @@ void DCC::ackManagerLoop(bool blocking) {
       case V0:
       case V1:      // Issue validate bit=0 or bit=1  packet
         {
-	  if (checkResets(blocking, RESET_MIN)) return; 
-          if (Diag::ACK) DIAG(F("\nV%d cv=%d bit=%d"),opcode==V1, ackManagerCv,ackManagerBitNum); 
+	  if (checkResets(RESET_MIN)) return; 
+          if (Diag::ACK) DIAG(F("V%d cv=%d bit=%d"),opcode==V1, ackManagerCv,ackManagerBitNum); 
           byte instruction = VERIFY_BIT | (opcode==V0?BIT_OFF:BIT_ON) | ackManagerBitNum;
           byte message[] = {cv1(BIT_MANIPULATE, ackManagerCv), cv2(ackManagerCv), instruction };
           DCCWaveform::progTrack.schedulePacket(message, sizeof(message), PROG_REPEATS);
@@ -646,46 +811,60 @@ void DCC::ackManagerLoop(bool blocking) {
       case WACK:   // wait for ack (or absence of ack)
          {
           byte ackState=2; // keep polling
-          if (blocking) {
-            while(ackState==2) ackState=DCCWaveform::progTrack.getAck();
-          }
-          else {
-            ackState=DCCWaveform::progTrack.getAck();
-            if (ackState==2) return; // keep polling
-          }
+      
+          ackState=DCCWaveform::progTrack.getAck();
+          if (ackState==2) return; // keep polling
           ackReceived=ackState==1;
           break;  // we have a genuine ACK result
          }
      case ITC0:
      case ITC1:   // If True Callback(0 or 1)  (if prevous WACK got an ACK)
         if (ackReceived) {
-            ackManagerProg = NULL; // all done now
-	          callback(opcode==ITC0?0:1);
+            callback(opcode==ITC0?0:1);
             return;
           }
         break;
         
       case ITCB:   // If True callback(byte)
           if (ackReceived) {
-            ackManagerProg = NULL; // all done now
-	          callback(ackManagerByte);
+            callback(ackManagerByte);
+            return;
+          }
+        break;
+		    
+      case ITCBV:   // If True callback(byte) - Verify
+          if (ackReceived) {
+            if (ackManagerByte == ackManagerByteVerify) {
+               ackRetrySum ++;
+               LCD(1, F("v %d %d Sum=%d"), ackManagerCv, ackManagerByte, ackRetrySum);
+            }
+            callback(ackManagerByte);
+            return;
+          }
+        break;
+		    
+      case ITCB7:   // If True callback(byte & 0x7F)
+          if (ackReceived) {
+            callback(ackManagerByte & 0x7F);
             return;
           }
         break;
         
       case NAKFAIL:   // If nack callback(-1)
           if (!ackReceived) {
-            ackManagerProg = NULL; // all done now
-	          callback(-1);
+            callback(-1);
             return;
           }
         break;
         
-      case FAIL:  // callback(-1)
-           ackManagerProg = NULL;
-	         callback(-1);
+      case CALLFAIL:  // callback(-1)
+           callback(-1);
            return;
-           
+
+      case BIV:     // ackManagerByte initial value
+           ackManagerByte = ackManagerByteVerify;
+           break;
+
       case STARTMERGE:
            ackManagerBitNum=7;
            ackManagerByte=0;     
@@ -700,12 +879,25 @@ void DCC::ackManagerLoop(bool blocking) {
 
       case SETBIT:
           ackManagerProg++; 
-          ackManagerBitNum=pgm_read_byte_near(ackManagerProg);
+          ackManagerBitNum=GETFLASH(ackManagerProg);
           break;
 
      case SETCV:
           ackManagerProg++; 
-          ackManagerCv=pgm_read_byte_near(ackManagerProg);
+          ackManagerCv=GETFLASH(ackManagerProg);
+          break;
+
+     case SETBYTE:
+          ackManagerProg++; 
+          ackManagerByte=GETFLASH(ackManagerProg);
+          break;
+
+    case SETBYTEH:
+          ackManagerByte=highByte(ackManagerWord);
+          break;
+          
+    case SETBYTEL:
+          ackManagerByte=lowByte(ackManagerWord);
           break;
 
      case STASHLOCOID:
@@ -714,7 +906,6 @@ void DCC::ackManagerLoop(bool blocking) {
           
      case COMBINELOCOID: 
           // ackManagerStash is  cv17, ackManagerByte is CV 18
-          ackManagerProg=NULL;
           callback( ackManagerByte + ((ackManagerStash - 192) << 8));
           return;            
 
@@ -723,14 +914,13 @@ void DCC::ackManagerLoop(bool blocking) {
           // SKIP opcodes until SKIPTARGET found
           while (opcode!=SKIPTARGET) {
             ackManagerProg++; 
-            opcode=pgm_read_byte_near(ackManagerProg);
+            opcode=GETFLASH(ackManagerProg);
           }
           break;
      case SKIPTARGET: 
           break;     
      default: 
-          DIAG(F("\n!! ackOp %d FAULT!!"),opcode);
-          ackManagerProg=NULL;
+          DIAG(F("!! ackOp %d FAULT!!"),opcode);
           callback( -1);
           return;        
     
@@ -738,25 +928,83 @@ void DCC::ackManagerLoop(bool blocking) {
     ackManagerProg++;
   }
 }
+
 void DCC::callback(int value) {
-    if (DCCWaveform::progTrack.autoPowerOff) {
-      if (Diag::ACK) DIAG(F("\nAuto Prog power off"));
-      DCCWaveform::progTrack.doAutoPowerOff();
+    // check for automatic retry
+    if (value == -1 && ackManagerRetry > 0) {
+      ackRetrySum ++;
+      LCD(0, F("Retry %d %d Sum=%d"), ackManagerCv, ackManagerRetry, ackRetrySum);
+      ackManagerRetry --;
+      ackManagerProg = ackManagerProgStart;
+      return;
+    }
+
+    static unsigned long callbackStart;
+    // We are about to leave programming mode
+    // Rule 1: If we have written to a decoder we must maintain power for 100mS
+    // Rule 2: If we are re-joining the main track we must power off for 30mS
+
+    switch (callbackState) {    
+       case AFTER_WRITE:  // first attempt to callback after a write operation
+	    if (!ackManagerRejoin && !DCCWaveform::progTrack.autoPowerOff) {
+               callbackState=READY;
+               break;
+            }                              // lines 906-910 added. avoid wait after write. use 1 PROG
+            callbackStart=millis();
+            callbackState=WAITING_100;
+            if (Diag::ACK) DIAG(F("Stable 100mS"));
+            break;
+            
+       case WAITING_100:  // waiting for 100mS
+            if (millis()-callbackStart < 100) break;
+            // stable after power maintained for 100mS
+
+            // If we are going to power off anyway, it doesnt matter
+            // but if we will keep the power on, we must off it for 30mS
+            if (DCCWaveform::progTrack.autoPowerOff) callbackState=READY;
+            else { // Need to cycle power off and on
+                DCCWaveform::progTrack.setPowerMode(POWERMODE::OFF); 
+                callbackStart=millis();
+                callbackState=WAITING_30;
+                if (Diag::ACK) DIAG(F("OFF 30mS"));
+            }
+            break;
+ 
+        case WAITING_30:  // waiting for 30mS with power off
+            if (millis()-callbackStart < 30) break;
+            //power has been off for 30mS
+            DCCWaveform::progTrack.setPowerMode(POWERMODE::ON); 
+            callbackState=READY;
+            break;
+     
+       case READY:  // ready after read, or write after power delay and off period.
+            // power off if we powered it on
+           if (DCCWaveform::progTrack.autoPowerOff) {
+              if (Diag::ACK) DIAG(F("Auto Prog power off"));
+              DCCWaveform::progTrack.doAutoPowerOff();
+           }
+          // Restore <1 JOIN> to state before BASELINE
+          if (ackManagerRejoin) {
+              setProgTrackSyncMain(true);
+              if (Diag::ACK) DIAG(F("Auto JOIN"));
+          }  
+    
+          ackManagerProg=NULL;  // no more steps to execute
+          if (Diag::ACK) DIAG(F("Callback(%d)"),value);
+          (ackManagerCallback)( value);
     }
-    if (Diag::ACK) DIAG(F("\nCallback(%d)\n"),value);
-    (ackManagerCallback)( value);
 }
 
- void DCC::displayCabList(Print * stream) {
+void DCC::displayCabList(Print * stream) {
 
     int used=0;
     for (int reg = 0; reg < MAX_LOCOS; reg++) {
        if (speedTable[reg].loco>0) {
         used ++;
-        StringFormatter::send(stream,F("\ncab=%d, speed=%d, dir=%c "),       
+        StringFormatter::send(stream,F("cab=%d, speed=%d, dir=%c \n"),       
            speedTable[reg].loco,  speedTable[reg].speedCode & 0x7f,(speedTable[reg].speedCode & 0x80) ? 'F':'R');
        }
      }
-     StringFormatter::send(stream,F("\nUsed=%d, max=%d\n"),used,MAX_LOCOS);
+     StringFormatter::send(stream,F("Used=%d, max=%d\n"),used,MAX_LOCOS);
      
 }

DCC.h

@@ -21,10 +21,11 @@
 #include <Arduino.h>
 #include "MotorDriver.h"
 #include "MotorDrivers.h"
+#include "FSH.h"
 
-typedef void (*ACK_CALLBACK)(int result);
+typedef void (*ACK_CALLBACK)(int16_t result);
 
-enum ackOp
+enum ackOp : byte
 {           // Program opcodes for the ack Manager
   BASELINE, // ensure enough resets sent before starting and obtain baseline current
   W0,
@@ -37,22 +38,38 @@ enum ackOp
   ITC1,             // If True Callback(1)  (if prevous WACK got an ACK)
   ITC0,             // If True callback(0);
   ITCB,             // If True callback(byte)
+  ITCBV,            // If True callback(byte) - end of Verify Byte
+  ITCB7,            // If True callback(byte &0x7F)
   NAKFAIL,          // if false callback(-1)
-  FAIL,             // callback(-1)
+  CALLFAIL,         // callback(-1)
+  BIV,              // Set ackManagerByte to initial value for Verify retry
   STARTMERGE,       // Clear bit and byte settings ready for merge pass
   MERGE,            // Merge previous wack response with byte value and decrement bit number (use for readimng CV bytes)
   SETBIT,           // sets bit number to next prog byte
   SETCV,            // sets cv number to next prog byte
+  SETBYTE,          // sets current byte to next prog byte
+  SETBYTEH,         // sets current byte to word high byte
+  SETBYTEL,         // sets current byte to word low byte
   STASHLOCOID,      // keeps current byte value for later
   COMBINELOCOID,    // combines current value with stashed value and returns it
   ITSKIP,           // skip to SKIPTARGET if ack true
   SKIPTARGET = 0xFF // jump to target
 };
 
+enum   CALLBACK_STATE : byte {
+  AFTER_WRITE,  // Start callback sequence after something was written to the decoder  
+  WAITING_100,        // Waiting for 100mS of stable power 
+  WAITING_30,         // waiting to 30ms of power off gap. 
+  READY,              // Ready to complete callback  
+  }; 
+
+
 // Allocations with memory implications..!
 // Base system takes approx 900 bytes + 8 per loco. Turnouts, Sensors etc are dynamically created
-#ifdef ARDUINO_AVR_UNO
+#if defined(ARDUINO_AVR_UNO)
 const byte MAX_LOCOS = 20;
+#elif defined(ARDUINO_AVR_NANO)
+const byte MAX_LOCOS = 30;
 #else
 const byte MAX_LOCOS = 50;
 #endif
@@ -60,7 +77,8 @@ const byte MAX_LOCOS = 50;
 class DCC
 {
 public:
-  static void begin(const __FlashStringHelper *motorShieldName, MotorDriver *mainDriver, MotorDriver *progDriver, byte timerNumber = 1);
+  static void begin(const FSH * motorShieldName, MotorDriver *mainDriver, MotorDriver *progDriver);
+  static void setJoinRelayPin(byte joinRelayPin);
   static void loop();
 
   // Public DCC API functions
@@ -70,31 +88,41 @@ public:
   static void writeCVByteMain(int cab, int cv, byte bValue);
   static void writeCVBitMain(int cab, int cv, byte bNum, bool bValue);
   static void setFunction(int cab, byte fByte, byte eByte);
-  static void setFn(int cab, byte functionNumber, bool on);
-  static int changeFn(int cab, byte functionNumber, bool pressed);
-  static int  getFn(int cab, byte functionNumber);
-  static void updateGroupflags(byte &flags, int functionNumber);
+  static void setFn(int cab, int16_t functionNumber, bool on);
+  static int changeFn(int cab, int16_t functionNumber, bool pressed);
+  static int  getFn(int cab, int16_t functionNumber);
+  static void updateGroupflags(byte &flags, int16_t functionNumber);
   static void setAccessory(int aAdd, byte aNum, bool activate);
   static bool writeTextPacket(byte *b, int nBytes);
   static void setProgTrackSyncMain(bool on); // when true, prog track becomes driveable
   static void setProgTrackBoost(bool on);    // when true, special prog track current limit does not apply
 
   // ACKable progtrack calls  bitresults callback 0,0 or -1, cv returns value or -1
-  static void readCV(int cv, ACK_CALLBACK callback, bool blocking = false);
-  static void readCVBit(int cv, byte bitNum, ACK_CALLBACK callback, bool blocking = false); // -1 for error
-  static void writeCVByte(int cv, byte byteValue, ACK_CALLBACK callback, bool blocking = false);
-  static void writeCVBit(int cv, byte bitNum, bool bitValue, ACK_CALLBACK callback, bool blocking = false);
-  static void verifyCVByte(int cv, byte byteValue, ACK_CALLBACK callback, bool blocking = false);
-  static void verifyCVBit(int cv, byte bitNum, bool bitValue, ACK_CALLBACK callback, bool blocking = false);
+  static void readCV(int16_t cv, ACK_CALLBACK callback);
+  static void readCVBit(int16_t cv, byte bitNum, ACK_CALLBACK callback); // -1 for error
+  static void writeCVByte(int16_t cv, byte byteValue, ACK_CALLBACK callback);
+  static void writeCVBit(int16_t cv, byte bitNum, bool bitValue, ACK_CALLBACK callback);
+  static void verifyCVByte(int16_t cv, byte byteValue, ACK_CALLBACK callback);
+  static void verifyCVBit(int16_t cv, byte bitNum, bool bitValue, ACK_CALLBACK callback);
 
-  static void getLocoId(ACK_CALLBACK callback, bool blocking = false);
+  static void getLocoId(ACK_CALLBACK callback);
+  static void setLocoId(int id,ACK_CALLBACK callback);
 
   // Enhanced API functions
   static void forgetLoco(int cab); // removes any speed reminders for this loco
   static void forgetAllLocos();    // removes all speed reminders
   static void displayCabList(Print *stream);
 
-  static __FlashStringHelper *getMotorShieldName();
+  static FSH *getMotorShieldName();
+  static inline void setGlobalSpeedsteps(byte s) {
+    globalSpeedsteps = s;
+  };
+  static inline int16_t setAckRetry(byte retry) {
+    ackRetry = retry;
+    ackRetryPSum = ackRetrySum;
+    ackRetrySum = 0;  // reset running total
+    return ackRetryPSum;
+  };
 
 private:
   struct LOCO
@@ -104,13 +132,15 @@ private:
     byte groupFlags;
     unsigned long functions;
   };
+  static byte joinRelay;
   static byte loopStatus;
   static void setThrottle2(uint16_t cab, uint8_t speedCode);
   static void updateLocoReminder(int loco, byte speedCode);
   static void setFunctionInternal(int cab, byte fByte, byte eByte);
   static bool issueReminder(int reg);
   static int nextLoco;
-  static __FlashStringHelper *shieldName;
+  static FSH *shieldName;
+  static byte globalSpeedsteps;
 
   static LOCO speedTable[MAX_LOCOS];
   static byte cv1(byte opcode, int cv);
@@ -121,17 +151,27 @@ private:
 
   // ACK MANAGER
   static ackOp const *ackManagerProg;
+  static ackOp const *ackManagerProgStart;
   static byte ackManagerByte;
+  static byte ackManagerByteVerify;
   static byte ackManagerBitNum;
   static int ackManagerCv;
+  static byte ackManagerRetry;
+  static byte ackRetry;
+  static int16_t ackRetrySum;
+  static int16_t ackRetryPSum;
+  static int ackManagerWord;
   static byte ackManagerStash;
   static bool ackReceived;
+  static bool ackManagerRejoin;
   static ACK_CALLBACK ackManagerCallback;
-  static void ackManagerSetup(int cv, byte bitNumOrbyteValue, ackOp const program[], ACK_CALLBACK callback, bool blocking);
-  static void ackManagerLoop(bool blocking);
-  static bool checkResets(bool blocking, uint8_t numResets);
+  static CALLBACK_STATE callbackState;
+  static void ackManagerSetup(int cv, byte bitNumOrbyteValue, ackOp const program[], ACK_CALLBACK callback);
+  static void ackManagerSetup(int wordval, ackOp const program[], ACK_CALLBACK callback);
+  static void ackManagerLoop();
+  static bool checkResets( uint8_t numResets);
   static const int PROG_REPEATS = 8; // repeats of programming commands (some decoders need at least 8 to be reliable)
-
+  
   // NMRA codes #
   static const byte SET_SPEED = 0x3f;
   static const byte WRITE_BYTE_MAIN = 0xEC;
@@ -156,9 +196,21 @@ private:
 #elif defined(ARDUINO_AVR_MEGA2560)
 #define ARDUINO_TYPE "MEGA"
 #elif defined(ARDUINO_ARCH_MEGAAVR)
-#define ARDUINO_TYPE "UNOWIFIR2"
-#elif defined(ARDUINO_SAMD_ZERO)
-  #define ARDUINO_TYPE    "FireBoxMK1"
+#define ARDUINO_TYPE "MEGAAVR"
+#elif defined(ARDUINO_TEENSY32)
+#define ARDUINO_TYPE "TEENSY32"
+#elif defined(ARDUINO_TEENSY35)
+#define ARDUINO_TYPE "TEENSY35"
+#elif defined(ARDUINO_TEENSY36)
+#define ARDUINO_TYPE "TEENSY36"
+#elif defined(ARDUINO_TEENSY40)
+#define ARDUINO_TYPE "TEENSY40"
+#elif defined(ARDUINO_TEENSY41)
+#define ARDUINO_TYPE "TEENSY41"
+#elif defined(ARDUINO_ARCH_ESP8266)
+#define ARDUINO_TYPE "ESP8266"
+#elif defined(ARDUINO_ARCH_ESP32)
+#define ARDUINO_TYPE "ESP32"
 #else
 #error CANNOT COMPILE - DCC++ EX ONLY WORKS WITH AN ARDUINO UNO, NANO 328, OR ARDUINO MEGA 1280/2560
 #endif

DCCEX.h

@@ -1,3 +1,24 @@
+/*
+ *  (c) 2020 Chris Harlow. All rights reserved.
+ *  (c) 2021 Fred Decker.  All rights reserved.
+ *  (c) 2020 Harald Barth. All rights reserved.
+ *  
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
 // This include is intended to visually simplify the .ino for the end users.
 // If there were any #ifdefs required they are much better handled in here.  
 
@@ -9,10 +30,29 @@
 #include "DIAG.h"
 #include "DCCEXParser.h"
 #include "version.h"
+#if defined(ARDUINO_ARCH_ESP8266)
+#include "WifiESP8266.h"
+#elif defined(ARDUINO_ARCH_ESP32)
+#include "WifiESP32.h"
+#else
 #include "WifiInterface.h"
-#include "EthernetInterface.h"
-#include "LCD_Implementation.h"
-#include "freeMemory.h"
-#include <Arduino.h>
-
+#endif
+#if ETHERNET_ON == true
+#include "EthernetInterface.h"
+#endif
+#include "LCD_Implementation.h"
+#include "LCN.h"
+#include "freeMemory.h"
+#include "IODevice.h"
+#include "Turnouts.h"
+#include "Sensors.h"
+#include "Outputs.h"
+#include "RMFT.h"
+
+// not yet in this branch
+//#if __has_include ( "myAutomation.h")
+//  #include "RMFT.h"
+//  #define RMFT_ACTIVE
+//#endif
+    
 #endif

DCCEXParser.cpp

@@ -17,9 +17,10 @@
  *  You should have received a copy of the GNU General Public License
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
+#include "DCC.h" // includes "Motordriver.h" and <Arduino.h>
+#include "defines.h"
 #include "StringFormatter.h"
 #include "DCCEXParser.h"
-#include "DCC.h"
 #include "DCCWaveform.h"
 #include "Turnouts.h"
 #include "Outputs.h"
@@ -27,33 +28,66 @@
 #include "freeMemory.h"
 #include "GITHUB_SHA.h"
 #include "version.h"
+#include "defines.h"
 
 #include "EEStore.h"
 #include "DIAG.h"
+#ifndef ESP_FAMILY
+#include <avr/wdt.h>
+#endif
+
+////////////////////////////////////////////////////////////////////////////////
+//
+// Figure out if we have enough memory for advanced features
+//
+#if defined(ARDUINO_AVR_UNO) || defined(ARDUINO_AVR_NANO)
+// nope
+#else
+#define HAS_ENOUGH_MEMORY
+#endif
 
 // These keywords are used in the <1> command. The number is what you get if you use the keyword as a parameter.
 // To discover new keyword numbers , use the <$ YOURKEYWORD> command
-const int HASH_KEYWORD_PROG = -29718;
-const int HASH_KEYWORD_MAIN = 11339;
-const int HASH_KEYWORD_JOIN = -30750;
-const int HASH_KEYWORD_CABS = -11981;
-const int HASH_KEYWORD_RAM = 25982;
-const int HASH_KEYWORD_CMD = 9962;
-const int HASH_KEYWORD_WIT = 31594;
-const int HASH_KEYWORD_WIFI = -5583;
-const int HASH_KEYWORD_ACK = 3113;
-const int HASH_KEYWORD_ON = 2657;
-const int HASH_KEYWORD_DCC = 6436;
-const int HASH_KEYWORD_SLOW = -17209;
-const int HASH_KEYWORD_PROGBOOST = -6353;
-const int HASH_KEYWORD_EEPROM = -7168;
-const int HASH_KEYWORD_LIMIT = 27413;
-const int HASH_KEYWORD_ETHERNET = -30767;    
+const int16_t HASH_KEYWORD_PROG = -29718;
+const int16_t HASH_KEYWORD_MAIN = 11339;
+const int16_t HASH_KEYWORD_JOIN = -30750;
+const int16_t HASH_KEYWORD_CABS = -11981;
+const int16_t HASH_KEYWORD_RAM = 25982;
+const int16_t HASH_KEYWORD_CMD = 9962;
+const int16_t HASH_KEYWORD_ACK = 3113;
+const int16_t HASH_KEYWORD_ON = 2657;
+const int16_t HASH_KEYWORD_DCC = 6436;
+const int16_t HASH_KEYWORD_SLOW = -17209;
+const int16_t HASH_KEYWORD_PROGBOOST = -6353;
+const int16_t HASH_KEYWORD_EEPROM = -7168;
+const int16_t HASH_KEYWORD_LIMIT = 27413;
+const int16_t HASH_KEYWORD_MAX = 16244;
+const int16_t HASH_KEYWORD_MIN = 15978;
+const int16_t HASH_KEYWORD_RESET = 26133;
+const int16_t HASH_KEYWORD_RETRY = 25704;
+const int16_t HASH_KEYWORD_SPEED28 = -17064;
+const int16_t HASH_KEYWORD_SPEED128 = 25816;
+const int16_t HASH_KEYWORD_SERVO=27709;
+const int16_t HASH_KEYWORD_VPIN=-415;
+const int16_t HASH_KEYWORD_C=67;
+const int16_t HASH_KEYWORD_T=84;
+const int16_t HASH_KEYWORD_LCN = 15137;
+const int16_t HASH_KEYWORD_HAL = 10853;
+const int16_t HASH_KEYWORD_SHOW = -21309;
+const int16_t HASH_KEYWORD_ANIN = -10424;
+const int16_t HASH_KEYWORD_ANOUT = -26399;
+#ifdef HAS_ENOUGH_MEMORY
+const int16_t HASH_KEYWORD_WIFI = -5583;
+const int16_t HASH_KEYWORD_ETHERNET = -30767;
+const int16_t HASH_KEYWORD_WIT = 31594;
+#endif
 
-int DCCEXParser::stashP[MAX_PARAMS];
+int16_t DCCEXParser::stashP[MAX_COMMAND_PARAMS];
 bool DCCEXParser::stashBusy;
 
 Print *DCCEXParser::stashStream = NULL;
+RingStream *DCCEXParser::stashRingStream = NULL;
+byte DCCEXParser::stashTarget=0;
 
 // This is a JMRI command parser, one instance per incoming stream
 // It doesnt know how the string got here, nor how it gets back.
@@ -65,7 +99,7 @@ DCCEXParser::DCCEXParser() {}
 void DCCEXParser::flush()
 {
     if (Diag::CMD)
-        DIAG(F("\nBuffer flush"));
+        DIAG(F("Buffer flush"));
     bufferLength = 0;
     inCommandPayload = false;
 }
@@ -88,7 +122,7 @@ void DCCEXParser::loop(Stream &stream)
         else if (ch == '>')
         {
             buffer[bufferLength] = '\0';
-            parse(&stream, buffer, false); // Parse this allowing async responses
+            parse(&stream, buffer, NULL); // Parse this (No ringStream for serial)
             inCommandPayload = false;
             break;
         }
@@ -100,19 +134,19 @@ void DCCEXParser::loop(Stream &stream)
     Sensor::checkAll(&stream); // Update and print changes
 }
 
-int DCCEXParser::splitValues(int result[MAX_PARAMS], const byte *cmd)
+int16_t DCCEXParser::splitValues(int16_t result[MAX_COMMAND_PARAMS], const byte *cmd)
 {
     byte state = 1;
     byte parameterCount = 0;
-    int runningValue = 0;
+    int16_t runningValue = 0;
     const byte *remainingCmd = cmd + 1; // skips the opcode
     bool signNegative = false;
 
     // clear all parameters in case not enough found
-    for (int i = 0; i < MAX_PARAMS; i++)
+    for (int16_t i = 0; i < MAX_COMMAND_PARAMS; i++)
         result[i] = 0;
 
-    while (parameterCount < MAX_PARAMS)
+    while (parameterCount < MAX_COMMAND_PARAMS)
     {
         byte hot = *remainingCmd;
 
@@ -141,6 +175,7 @@ int DCCEXParser::splitValues(int result[MAX_PARAMS], const byte *cmd)
                 runningValue = 10 * runningValue + (hot - '0');
                 break;
             }
+            if (hot >= 'a' && hot <= 'z') hot=hot-'a'+'A'; // uppercase a..z
             if (hot >= 'A' && hot <= 'Z')
             {
                 // Since JMRI got modified to send keywords in some rare cases, we need this
@@ -158,24 +193,98 @@ int DCCEXParser::splitValues(int result[MAX_PARAMS], const byte *cmd)
     return parameterCount;
 }
 
+int16_t DCCEXParser::splitHexValues(int16_t result[MAX_COMMAND_PARAMS], const byte *cmd)
+{
+    byte state = 1;
+    byte parameterCount = 0;
+    int16_t runningValue = 0;
+    const byte *remainingCmd = cmd + 1; // skips the opcode
+    
+    // clear all parameters in case not enough found
+    for (int16_t i = 0; i < MAX_COMMAND_PARAMS; i++)
+        result[i] = 0;
+
+    while (parameterCount < MAX_COMMAND_PARAMS)
+    {
+        byte hot = *remainingCmd;
+
+        switch (state)
+        {
+
+        case 1: // skipping spaces before a param
+            if (hot == ' ')
+                break;
+            if (hot == '\0' || hot == '>')
+                return parameterCount;
+            state = 2;
+            continue;
+
+        case 2: // checking first hex digit
+            runningValue = 0;
+            state = 3;
+            continue;
+
+        case 3: // building a parameter
+            if (hot >= '0' && hot <= '9')
+            {
+                runningValue = 16 * runningValue + (hot - '0');
+                break;
+            }
+            if (hot >= 'A' && hot <= 'F')
+            {
+                runningValue = 16 * runningValue + 10 + (hot - 'A');
+                break;
+            }
+            if (hot >= 'a' && hot <= 'f')
+            {
+                runningValue = 16 * runningValue + 10 + (hot - 'a');
+                break;
+            }
+            if (hot==' ' || hot=='>' || hot=='\0') { 
+               result[parameterCount] = runningValue;
+               parameterCount++;
+               state = 1;
+               continue;
+            }
+            return -1; // invalid hex digit
+        }
+        remainingCmd++;
+    }
+    return parameterCount;
+}
+
 FILTER_CALLBACK DCCEXParser::filterCallback = 0;
+FILTER_CALLBACK DCCEXParser::filterRMFTCallback = 0;
 AT_COMMAND_CALLBACK DCCEXParser::atCommandCallback = 0;
 void DCCEXParser::setFilter(FILTER_CALLBACK filter)
 {
     filterCallback = filter;
 }
+void DCCEXParser::setRMFTFilter(FILTER_CALLBACK filter)
+{
+    filterRMFTCallback = filter;
+}
 void DCCEXParser::setAtCommandCallback(AT_COMMAND_CALLBACK callback)
 {
     atCommandCallback = callback;
 }
 
+// Parse an F() string 
+void DCCEXParser::parse(const FSH * cmd) {
+      int size=strlen_P((char *)cmd)+1; 
+      char buffer[size];
+      strcpy_P(buffer,(char *)cmd);
+      parse(&Serial,(byte *)buffer,NULL);
+}
+
 // See documentation on DCC class for info on this section
-void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
+
+void DCCEXParser::parse(Print *stream, byte *com, RingStream * ringStream)
 {
     (void)EEPROM; // tell compiler not to warn this is unused
     if (Diag::CMD)
-        DIAG(F("\nPARSING:%s\n"), com);
-    int p[MAX_PARAMS];
+        DIAG(F("PARSING:%s"), com);
+    int16_t p[MAX_COMMAND_PARAMS];
     while (com[0] == '<' || com[0] == ' ')
         com++; // strip off any number of < or spaces
     byte params = splitValues(p, com);
@@ -183,6 +292,8 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
 
     if (filterCallback)
         filterCallback(stream, opcode, params, p);
+    if (filterRMFTCallback && opcode!='\0')
+        filterRMFTCallback(stream, opcode, params, p);
 
     // Functions return from this switch if complete, break from switch implies error <X> to send
     switch (opcode)
@@ -191,9 +302,9 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
         return; // filterCallback asked us to ignore
     case 't':   // THROTTLE <t [REGISTER] CAB SPEED DIRECTION>
     {
-        int cab;
-        int tspeed;
-        int direction;
+        int16_t cab;
+        int16_t tspeed;
+        int16_t direction;
 
         if (params == 4)
         { // <t REGISTER CAB SPEED DIRECTION>
@@ -210,7 +321,8 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
         else
             break;
 
-        // Convert JMRI bizarre -1=emergency stop, 0-126 as speeds
+        // Convert DCC-EX protocol speed steps where
+        // -1=emergency stop, 0-126 as speeds
         // to DCC 0=stop, 1= emergency stop, 2-127 speeds
         if (tspeed > 126 || tspeed < -1)
             break; // invalid JMRI speed code
@@ -226,9 +338,9 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
 
         DCC::setThrottle(cab, tspeed, direction);
         if (params == 4)
-            StringFormatter::send(stream, F("<T %d %d %d>"), p[0], p[2], p[3]);
+            StringFormatter::send(stream, F("<T %d %d %d>\n"), p[0], p[2], p[3]);
         else
-            StringFormatter::send(stream, F("<O>"));
+            StringFormatter::send(stream, F("<O>\n"));
         return;
     }
     case 'f': // FUNCTION <f CAB BYTE1 [BYTE2]>
@@ -236,12 +348,37 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
             return;
         break;
 
-    case 'a': // ACCESSORY <a ADDRESS SUBADDRESS ACTIVATE>
-        if (p[2] != (p[2] & 1))
-            return;
-        DCC::setAccessory(p[0], p[1], p[2] == 1);
+    case 'a': // ACCESSORY <a ADDRESS SUBADDRESS ACTIVATE> or <a LINEARADDRESS ACTIVATE>
+        { 
+          int address;
+          byte subaddress;
+          byte activep;
+          if (params==2) { // <a LINEARADDRESS ACTIVATE>
+              address=(p[0] - 1) / 4 + 1;
+              subaddress=(p[0] - 1)  % 4;
+              activep=1;        
+          }
+          else if (params==3) { // <a ADDRESS SUBADDRESS ACTIVATE>
+              address=p[0];
+              subaddress=p[1];
+              activep=2;        
+          }
+          else break; // invalid no of parameters
+          
+          if (
+             ((address & 0x01FF) != address)      // invalid address (limit 9 bits ) 
+          || ((subaddress & 0x03) != subaddress)  // invalid subaddress (limit 2 bits ) 
+          || ((p[activep]  & 0x01) != p[activep]) // invalid activate 0|1
+          ) break; 
+          // Honour the configuration option (config.h) which allows the <a> command to be reversed
+#ifdef DCC_ACCESSORY_RCN_213
+          DCC::setAccessory(address, subaddress,p[activep]==0);
+#else
+          DCC::setAccessory(address, subaddress,p[activep]==1);
+#endif
+        }
         return;
-
+     
     case 'T': // TURNOUT  <T ...>
         if (parseT(stream, params, p))
             return;
@@ -265,48 +402,66 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
         DCC::writeCVBitMain(p[0], p[1], p[2], p[3]);
         return;
 
+    case 'M': // WRITE TRANSPARENT DCC PACKET MAIN <M REG X1 ... X9>
+    case 'P': // WRITE TRANSPARENT DCC PACKET PROG <P REG X1 ... X9>
+        // Re-parse the command using a hex-only splitter
+        params=splitHexValues(p,com)-1; // drop REG
+        if (params<1) break;  
+        {
+          byte packet[params];
+          for (int i=0;i<params;i++) {
+            packet[i]=(byte)p[i+1];
+            if (Diag::CMD) DIAG(F("packet[%d]=%d (0x%x)"), i, packet[i], packet[i]);
+          }
+          (opcode=='M'?DCCWaveform::mainTrack:DCCWaveform::progTrack).schedulePacket(packet,params,3);  
+        }
+        return;
+        
     case 'W': // WRITE CV ON PROG <W CV VALUE CALLBACKNUM CALLBACKSUB>
-        if (!stashCallback(stream, p))
-            break;
-        DCC::writeCVByte(p[0], p[1], callback_W, blocking);
+            if (!stashCallback(stream, p, ringStream))
+                break;
+        if (params == 1) // <W id> Write new loco id (clearing consist and managing short/long)
+            DCC::setLocoId(p[0],callback_Wloco);
+        else // WRITE CV ON PROG <W CV VALUE [CALLBACKNUM] [CALLBACKSUB]>
+            DCC::writeCVByte(p[0], p[1], callback_W);
         return;
 
     case 'V': // VERIFY CV ON PROG <V CV VALUE> <V CV BIT 0|1>
         if (params == 2)
         { // <V CV VALUE>
-            if (!stashCallback(stream, p))
+            if (!stashCallback(stream, p, ringStream))
                 break;
-            DCC::verifyCVByte(p[0], p[1], callback_Vbyte, blocking);
+            DCC::verifyCVByte(p[0], p[1], callback_Vbyte);
             return;
         }
         if (params == 3)
         {
-            if (!stashCallback(stream, p))
+            if (!stashCallback(stream, p, ringStream))
                 break;
-            DCC::verifyCVBit(p[0], p[1], p[2], callback_Vbit, blocking);
+            DCC::verifyCVBit(p[0], p[1], p[2], callback_Vbit);
             return;
         }
         break;
 
     case 'B': // WRITE CV BIT ON PROG <B CV BIT VALUE CALLBACKNUM CALLBACKSUB>
-        if (!stashCallback(stream, p))
+        if (!stashCallback(stream, p, ringStream))
             break;
-        DCC::writeCVBit(p[0], p[1], p[2], callback_B, blocking);
+        DCC::writeCVBit(p[0], p[1], p[2], callback_B);
         return;
 
     case 'R': // READ CV ON PROG
         if (params == 3)
         { // <R CV CALLBACKNUM CALLBACKSUB>
-            if (!stashCallback(stream, p))
+            if (!stashCallback(stream, p, ringStream))
                 break;
-            DCC::readCV(p[0], callback_R, blocking);
+            DCC::readCV(p[0], callback_R);
             return;
         }
         if (params == 0)
         { // <R> New read loco id
-            if (!stashCallback(stream, p))
+            if (!stashCallback(stream, p, ringStream))
                 break;
-            DCC::getLocoId(callback_Rloco, blocking);
+            DCC::getLocoId(callback_Rloco);
             return;
         }
         break;
@@ -318,27 +473,31 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
         {
             POWERMODE mode = opcode == '1' ? POWERMODE::ON : POWERMODE::OFF;
             DCC::setProgTrackSyncMain(false); // Only <1 JOIN> will set this on, all others set it off
-            if (params == 0)
+            if (params == 0 ||
+		(MotorDriver::commonFaultPin && p[0] != HASH_KEYWORD_JOIN)) // commonFaultPin prevents individual track handling
             {
                 DCCWaveform::mainTrack.setPowerMode(mode);
                 DCCWaveform::progTrack.setPowerMode(mode);
 		if (mode == POWERMODE::OFF)
 		  DCC::setProgTrackBoost(false);  // Prog track boost mode will not outlive prog track off
-                StringFormatter::send(stream, F("<p%c>"), opcode);
+                StringFormatter::send(stream, F("<p%c>\n"), opcode);
+		        LCD(2, F("p%c"), opcode);
                 return;
             }
             switch (p[0])
             {
             case HASH_KEYWORD_MAIN:
                 DCCWaveform::mainTrack.setPowerMode(mode);
-                StringFormatter::send(stream, F("<p%c MAIN>"), opcode);
+                StringFormatter::send(stream, F("<p%c MAIN>\n"), opcode);
+	            LCD(2, F("p%c MAIN"), opcode);
                 return;
 
             case HASH_KEYWORD_PROG:
                 DCCWaveform::progTrack.setPowerMode(mode);
 		if (mode == POWERMODE::OFF)
 		  DCC::setProgTrackBoost(false);  // Prog track boost mode will not outlive prog track off
-                StringFormatter::send(stream, F("<p%c PROG>"), opcode);
+                StringFormatter::send(stream, F("<p%c PROG>\n"), opcode);
+		        LCD(2, F("p%c PROG"), opcode);
                 return;
             case HASH_KEYWORD_JOIN:
                 DCCWaveform::mainTrack.setPowerMode(mode);
@@ -346,18 +505,29 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
                 if (mode == POWERMODE::ON)
                 {
                     DCC::setProgTrackSyncMain(true);
-                    StringFormatter::send(stream, F("<p1 JOIN>"), opcode);
+                    StringFormatter::send(stream, F("<p1 JOIN>\n"), opcode);
+		            LCD(2, F("p1 JOIN"));
                 }
                 else
-                    StringFormatter::send(stream, F("<p0>"));
+		        {
+                    StringFormatter::send(stream, F("<p0>\n"));
+		            LCD(2, F("p0"));
+	    	    }
                 return;
             }
             break;
         }
         return;
 
-    case 'c': // READ CURRENT <c>
-        StringFormatter::send(stream, F("<a %d>"), DCCWaveform::mainTrack.getLastCurrent());
+    case '!': // ESTOP ALL  <!>
+        DCC::setThrottle(0,1,1); // this broadcasts speed 1(estop) and sets all reminders to speed 1. 
+        return;
+
+    case 'c': // SEND METER RESPONSES <c>
+        //                               <c MeterName value C/V unit min max res warn>
+        StringFormatter::send(stream, F("<c CurrentMAIN %d C Milli 0 %d 1 %d>\n"), DCCWaveform::mainTrack.getCurrentmA(), 
+            DCCWaveform::mainTrack.getMaxmA(), DCCWaveform::mainTrack.getTripmA());
+        StringFormatter::send(stream, F("<a %d>\n"), DCCWaveform::mainTrack.get1024Current()); //'a' message deprecated, remove once JMRI 4.22 is available
         return;
 
     case 'Q': // SENSORS <Q>
@@ -365,20 +535,22 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
         return;
 
     case 's': // <s>
-        StringFormatter::send(stream, F("<p%d>"), DCCWaveform::mainTrack.getPowerMode() == POWERMODE::ON);
-        StringFormatter::send(stream, F("<iDCC-EX V-%S / %S / %S G-%S>"), F(VERSION), F(ARDUINO_TYPE), DCC::getMotorShieldName(), F(GITHUB_SHA));
+        StringFormatter::send(stream, F("<p%d>\n"), DCCWaveform::mainTrack.getPowerMode() == POWERMODE::ON);
+        StringFormatter::send(stream, F("<iDCC-EX V-%S / %S / %S G-%S>\n"), F(VERSION), F(ARDUINO_TYPE), DCC::getMotorShieldName(), F(GITHUB_SHA));
+        Turnout::printAll(stream); //send all Turnout states
+        Output::printAll(stream);  //send all Output  states
+        Sensor::printAll(stream);  //send all Sensor  states
         // TODO Send stats of  speed reminders table
-        // TODO send status of turnouts etc etc
-        return;
+        return;       
 
     case 'E': // STORE EPROM <E>
         EEStore::store();
-        StringFormatter::send(stream, F("<e %d %d %d>"), EEStore::eeStore->data.nTurnouts, EEStore::eeStore->data.nSensors, EEStore::eeStore->data.nOutputs);
+        StringFormatter::send(stream, F("<e %d %d %d>\n"), EEStore::eeStore->data.nTurnouts, EEStore::eeStore->data.nSensors, EEStore::eeStore->data.nOutputs);
         return;
 
     case 'e': // CLEAR EPROM <e>
         EEStore::clear();
-        StringFormatter::send(stream, F("<O>"));
+        StringFormatter::send(stream, F("<O>\n"));
         return;
 
     case ' ': // < >
@@ -391,7 +563,13 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
         return;
 
     case '#': // NUMBER OF LOCOSLOTS <#>
-        StringFormatter::send(stream, F("<# %d>"), MAX_LOCOS);
+        StringFormatter::send(stream, F("<# %d>\n"), MAX_LOCOS);
+        return;
+
+    case '-': // Forget Loco <- [cab]>
+        if (params > 1 || p[0]<0) break;
+        if (p[0]==0) DCC::forgetAllLocos();
+        else  DCC::forgetLoco(p[0]);
         return;
 
     case 'F': // New command to call the new Loco Function API <F cab func 1|0>
@@ -402,24 +580,26 @@ void DCCEXParser::parse(Print *stream, byte *com, bool blocking)
 
     case '+': // Complex Wifi interface command (not usual parse)
         if (atCommandCallback) {
+          DCCWaveform::mainTrack.setPowerMode(POWERMODE::OFF);
+          DCCWaveform::progTrack.setPowerMode(POWERMODE::OFF);
           atCommandCallback(com);
           return;
         }
         break;
 
     default: //anything else will diagnose and drop out to <X>
-        DIAG(F("\nOpcode=%c params=%d\n"), opcode, params);
+        DIAG(F("Opcode=%c params=%d"), opcode, params);
         for (int i = 0; i < params; i++)
-            DIAG(F("p[%d]=%d (0x%x)\n"), i, p[i], p[i]);
+            DIAG(F("p[%d]=%d (0x%x)"), i, p[i], p[i]);
         break;
 
     } // end of opcode switch
 
     // Any fallout here sends an <X>
-    StringFormatter::send(stream, F("<X>"));
+    StringFormatter::send(stream, F("<X>\n"));
 }
 
-bool DCCEXParser::parseZ(Print *stream, int params, int p[])
+bool DCCEXParser::parseZ(Print *stream, int16_t params, int16_t p[])
 {
 
     switch (params)
@@ -431,29 +611,31 @@ bool DCCEXParser::parseZ(Print *stream, int params, int p[])
         if (o == NULL)
             return false;
         o->activate(p[1]);
-        StringFormatter::send(stream, F("<Y %d %d>"), p[0], p[1]);
+        StringFormatter::send(stream, F("<Y %d %d>\n"), p[0], p[1]);
     }
         return true;
 
-    case 3: // <Z ID PIN INVERT>
+    case 3: // <Z ID PIN IFLAG>
+        if (p[0] < 0 || p[2] < 0 || p[2] > 7 )
+	        return false;
         if (!Output::create(p[0], p[1], p[2], 1))
           return false;
-        StringFormatter::send(stream, F("<O>"));
+        StringFormatter::send(stream, F("<O>\n"));
         return true;
 
     case 1: // <Z ID>
         if (!Output::remove(p[0]))
           return false;
-        StringFormatter::send(stream, F("<O>"));
+        StringFormatter::send(stream, F("<O>\n"));
         return true;
 
-    case 0: // <Z>
+    case 0: // <Z> list Output definitions
     {
         bool gotone = false;
         for (Output *tt = Output::firstOutput; tt != NULL; tt = tt->nextOutput)
         {
             gotone = true;
-            StringFormatter::send(stream, F("<Y %d %d %d %d>"), tt->data.id, tt->data.pin, tt->data.iFlag, tt->data.oStatus);
+            StringFormatter::send(stream, F("<Y %d %d %d %d>\n"), tt->data.id, tt->data.pin, tt->data.flags, tt->data.active);
         }
         return gotone;
     }
@@ -463,7 +645,7 @@ bool DCCEXParser::parseZ(Print *stream, int params, int p[])
 }
 
 //===================================
-bool DCCEXParser::parsef(Print *stream, int params, int p[])
+bool DCCEXParser::parsef(Print *stream, int16_t params, int16_t p[])
 {
     // JMRI sends this info in DCC message format but it's not exactly
     //      convenient for other processing
@@ -495,9 +677,9 @@ bool DCCEXParser::parsef(Print *stream, int params, int p[])
     return true;
 }
 
-void DCCEXParser::funcmap(int cab, byte value, byte fstart, byte fstop)
+void DCCEXParser::funcmap(int16_t cab, byte value, byte fstart, byte fstop)
 {
-    for (int i = fstart; i <= fstop; i++)
+    for (int16_t i = fstart; i <= fstop; i++)
     {
         DCC::setFn(cab, i, value & 1);
         value >>= 1;
@@ -505,17 +687,17 @@ void DCCEXParser::funcmap(int cab, byte value, byte fstart, byte fstop)
 }
 
 //===================================
-bool DCCEXParser::parseT(Print *stream, int params, int p[])
+bool DCCEXParser::parseT(Print *stream, int16_t params, int16_t p[])
 {
     switch (params)
     {
-    case 0: // <T>  show all turnouts
+    case 0: // <T>  list turnout definitions
     {
         bool gotOne = false;
-        for (Turnout *tt = Turnout::firstTurnout; tt != NULL; tt = tt->nextTurnout)
+        for (Turnout *tt = Turnout::first(); tt != NULL; tt = tt->next())
         {
             gotOne = true;
-            StringFormatter::send(stream, F("<H %d %d>"), tt->data.id, tt->data.tStatus & STATUS_ACTIVE);
+            tt->print(stream);
         }
         return gotOne; // will <X> if none found
     }
@@ -523,31 +705,69 @@ bool DCCEXParser::parseT(Print *stream, int params, int p[])
     case 1: // <T id>  delete turnout
         if (!Turnout::remove(p[0]))
             return false;
-        StringFormatter::send(stream, F("<O>"));
+        StringFormatter::send(stream, F("<O>\n"));
         return true;
 
-    case 2: // <T id 0|1>  activate turnout
-    {
-        Turnout *tt = Turnout::get(p[0]);
-        if (!tt)
-            return false;
-        tt->activate(p[1]);
-        StringFormatter::send(stream, F("<H %d %d>"), tt->data.id, tt->data.tStatus & STATUS_ACTIVE);
-    }
-        return true;
+    case 2: // <T id 0|1|T|C> 
+        {
+          bool state = false;
+          switch (p[1]) {
+            // Turnout messages use 1=throw, 0=close.
+            case 0:
+            case HASH_KEYWORD_C:
+              state = true;
+              break;
+            case 1:
+            case HASH_KEYWORD_T:
+              state= false;
+              break;
+            default:
+              return false;  // Invalid parameter
+          }
+          if (!Turnout::setClosed(p[0], state)) return false;
 
-    case 3: // <T id addr subaddr>  define turnout
-        if (!Turnout::create(p[0], p[1], p[2]))
-            return false;
-        StringFormatter::send(stream, F("<O>"));
-        return true;
+          // Send acknowledgement to caller if the command was not received over Serial
+          // (acknowledgement messages on Serial are sent by the Turnout class).
+          if (stream != &Serial) Turnout::printState(p[0], stream);
+          return true;
+        }
 
-    default:
-        return false; // will <x>
+    default: // Anything else is some kind of turnout create function.
+      if (params == 6 && p[1] == HASH_KEYWORD_SERVO) { // <T id SERVO n n n n>
+        if (!ServoTurnout::create(p[0], (VPIN)p[2], (uint16_t)p[3], (uint16_t)p[4], (uint8_t)p[5]))
+          return false;
+      } else 
+      if (params == 3 && p[1] == HASH_KEYWORD_VPIN) { // <T id VPIN n>
+        if (!VpinTurnout::create(p[0], p[2])) return false;
+      } else 
+      if (params >= 3 && p[1] == HASH_KEYWORD_DCC) {
+        // <T id DCC addr subadd>   0<=addr<=511, 0<=subadd<=3 (like <a> command).<T>
+        if (params==4 && p[2]>=0 && p[2]<512 && p[3]>=0 && p[3]<4) { // <T id DCC n m>
+          if (!DCCTurnout::create(p[0], p[2], p[3])) return false;
+        } else if (params==3 && p[2]>0 && p[2]<=512*4) { // <T id DCC nn>, 1<=nn<=2048
+          // Linearaddress 1 maps onto decoder address 1/0 (not 0/0!).
+          if (!DCCTurnout::create(p[0], (p[2]-1)/4+1, (p[2]-1)%4)) return false;
+        } else
+          return false;
+      } else 
+      if (params==3) { // legacy <T id addr subadd> for DCC accessory
+        if (p[1]>=0 && p[1]<512 && p[2]>=0 && p[2]<4) {
+          if (!DCCTurnout::create(p[0], p[1], p[2])) return false;
+        } else
+          return false;
+      } 
+      else 
+      if (params==4) { // legacy <T id n n n> for Servo
+        if (!ServoTurnout::create(p[0], (VPIN)p[1], (uint16_t)p[2], (uint16_t)p[3], 1)) return false;
+      } else
+        return false;
+
+      StringFormatter::send(stream, F("<O>\n"));
+      return true;
     }
 }
 
-bool DCCEXParser::parseS(Print *stream, int params, int p[])
+bool DCCEXParser::parseS(Print *stream, int16_t params, int16_t p[])
 {
 
     switch (params)
@@ -555,23 +775,23 @@ bool DCCEXParser::parseS(Print *stream, int params, int p[])
     case 3: // <S id pin pullup>  create sensor. pullUp indicator (0=LOW/1=HIGH)
         if (!Sensor::create(p[0], p[1], p[2]))
           return false;
-        StringFormatter::send(stream, F("<O>"));
+        StringFormatter::send(stream, F("<O>\n"));
         return true;
 
     case 1: // S id> remove sensor
         if (!Sensor::remove(p[0]))
           return false;
-        StringFormatter::send(stream, F("<O>"));
+        StringFormatter::send(stream, F("<O>\n"));
         return true;
 
-    case 0: // <S> lit sensor states
-	if (Sensor::firstSensor == NULL)
-	    return false;
-        for (Sensor *tt = Sensor::firstSensor; tt != NULL; tt = tt->nextSensor)
-        {
-            StringFormatter::send(stream, F("<Q %d %d %d>"), tt->data.snum, tt->data.pin, tt->data.pullUp);
-        }
-        return true;
+    case 0: // <S> list sensor definitions
+      if (Sensor::firstSensor == NULL)
+        return false;
+      for (Sensor *tt = Sensor::firstSensor; tt != NULL; tt = tt->nextSensor)
+      {
+          StringFormatter::send(stream, F("<Q %d %d %d>\n"), tt->data.snum, tt->data.pin, tt->data.pullUp);
+      }
+      return true;
 
     default: // invalid number of arguments
         break;
@@ -579,7 +799,7 @@ bool DCCEXParser::parseS(Print *stream, int params, int p[])
     return false;
 }
 
-bool DCCEXParser::parseD(Print *stream, int params, int p[])
+bool DCCEXParser::parseD(Print *stream, int16_t params, int16_t p[])
 {
     if (params == 0)
         return false;
@@ -591,26 +811,40 @@ bool DCCEXParser::parseD(Print *stream, int params, int p[])
         return true;
 
     case HASH_KEYWORD_RAM: // <D RAM>
-        StringFormatter::send(stream, F("\nFree memory=%d\n"), freeMemory());
+        StringFormatter::send(stream, F("Free memory=%d\n"), minimumFreeMemory());
         break;
 
-    case HASH_KEYWORD_ACK: // <D ACK ON/OFF>
-	if (params >= 2 && p[1] == HASH_KEYWORD_LIMIT) {
-	  DCCWaveform::progTrack.setAckLimit(p[2]);
-          StringFormatter::send(stream, F("\nAck limit=%dmA\n"), p[2]);
-	} else
+    case HASH_KEYWORD_ACK: // <D ACK ON/OFF> <D ACK [LIMIT|MIN|MAX|RETRY] Value>
+	if (params >= 3) {
+	    if (p[1] == HASH_KEYWORD_LIMIT) {
+	      DCCWaveform::progTrack.setAckLimit(p[2]);
+	      LCD(1, F("Ack Limit=%dmA"), p[2]);  // <D ACK LIMIT 42>
+	    } else if (p[1] == HASH_KEYWORD_MIN) {
+	      DCCWaveform::progTrack.setMinAckPulseDuration(p[2]);
+	      LCD(0, F("Ack Min=%dus"), p[2]);  //   <D ACK MIN 1500>
+	    } else if (p[1] == HASH_KEYWORD_MAX) {
+	      DCCWaveform::progTrack.setMaxAckPulseDuration(p[2]);
+	      LCD(0, F("Ack Max=%dus"), p[2]);  //   <D ACK MAX 9000>
+	    } else if (p[1] == HASH_KEYWORD_RETRY) {
+	      if (p[2] >255) p[2]=3;
+	      LCD(0, F("Ack Retry=%d Sum=%d"), p[2], DCC::setAckRetry(p[2]));  //   <D ACK RETRY 2>
+	    }
+	} else {
+	  StringFormatter::send(stream, F("Ack diag %S\n"), onOff ? F("on") : F("off"));
 	  Diag::ACK = onOff;
+	}
         return true;
 
     case HASH_KEYWORD_CMD: // <D CMD ON/OFF>
         Diag::CMD = onOff;
         return true;
 
+#ifdef HAS_ENOUGH_MEMORY
     case HASH_KEYWORD_WIFI: // <D WIFI ON/OFF>
         Diag::WIFI = onOff;
         return true;
 
-   case HASH_KEYWORD_ETHERNET: // <D ETHERNET ON/OFF>
+    case HASH_KEYWORD_ETHERNET: // <D ETHERNET ON/OFF>
         Diag::ETHERNET = onOff;
         return true;
 
@@ -618,19 +852,57 @@ bool DCCEXParser::parseD(Print *stream, int params, int p[])
         Diag::WITHROTTLE = onOff;
         return true;
 
-    case HASH_KEYWORD_DCC:
-        DCCWaveform::setDiagnosticSlowWave(params >= 1 && p[1] == HASH_KEYWORD_SLOW);
+    case HASH_KEYWORD_LCN: // <D LCN ON/OFF>
+        Diag::LCN = onOff;
         return true;
+#endif
 
     case HASH_KEYWORD_PROGBOOST:
         DCC::setProgTrackBoost(true);
-	return true;
+	      return true;
 
-    case HASH_KEYWORD_EEPROM:
-	if (params >= 1)
+    case HASH_KEYWORD_RESET:
+        {
+#ifndef ESP_FAMILY
+          wdt_enable( WDTO_15MS); // set Arduino watchdog timer for 15ms
+          delay(50);              // wait for the prescaler time to expire
+#else
+	  /* XXX do right thing to reboot */
+#endif
+          break; // and <X> if we didnt restart 
+        }
+        
+    case HASH_KEYWORD_EEPROM: // <D EEPROM NumEntries>
+	if (params >= 2)
 	    EEStore::dump(p[1]);
 	return true;
 
+    case HASH_KEYWORD_SPEED28:
+        DCC::setGlobalSpeedsteps(28);
+	StringFormatter::send(stream, F("28 Speedsteps"));
+        return true;
+
+    case HASH_KEYWORD_SPEED128:
+        DCC::setGlobalSpeedsteps(128);
+	StringFormatter::send(stream, F("128 Speedsteps"));
+        return true;
+
+    case HASH_KEYWORD_SERVO:  // <D SERVO vpin position [profile]>
+    case HASH_KEYWORD_ANOUT:  // <D ANOUT vpin position [profile]>
+        IODevice::writeAnalogue(p[1], p[2], params>3 ? p[3] : 0);
+        break;
+
+    case HASH_KEYWORD_ANIN:   // <D ANIN vpin>  Display analogue input value
+        DIAG(F("VPIN=%d value=%d"), p[1], IODevice::readAnalogue(p[1]));
+        break;
+
+#if !defined(IO_MINIMAL_HAL)
+    case HASH_KEYWORD_HAL: 
+        if (p[1] == HASH_KEYWORD_SHOW) 
+          IODevice::DumpAll();
+        break;
+#endif
+
     default: // invalid/unknown
         break;
     }
@@ -638,45 +910,70 @@ bool DCCEXParser::parseD(Print *stream, int params, int p[])
 }
 
 // CALLBACKS must be static
-bool DCCEXParser::stashCallback(Print *stream, int p[MAX_PARAMS])
+bool DCCEXParser::stashCallback(Print *stream, int16_t p[MAX_COMMAND_PARAMS], RingStream * ringStream)
 {
     if (stashBusy )
         return false;
     stashBusy = true;
     stashStream = stream;
-    memcpy(stashP, p, MAX_PARAMS * sizeof(p[0]));
+    stashRingStream=ringStream;
+    if (ringStream) stashTarget= ringStream->peekTargetMark();
+    memcpy(stashP, p, MAX_COMMAND_PARAMS * sizeof(p[0]));
     return true;
 }
-void DCCEXParser::callback_W(int result)
-{
-    StringFormatter::send(stashStream, F("<r%d|%d|%d %d>"), stashP[2], stashP[3], stashP[0], result == 1 ? stashP[1] : -1);
-    stashBusy = false;
+
+Print * DCCEXParser::getAsyncReplyStream() {
+       if (stashRingStream) {
+           stashRingStream->mark(stashTarget);
+           return stashRingStream;
+       }
+       return stashStream;
 }
 
-void DCCEXParser::callback_B(int result)
-{
-    StringFormatter::send(stashStream, F("<r%d|%d|%d %d %d>"), stashP[3], stashP[4], stashP[0], stashP[1], result == 1 ? stashP[2] : -1);
-    stashBusy = false;
-}
-void DCCEXParser::callback_Vbit(int result)
-{
-    StringFormatter::send(stashStream, F("<v %d %d %d>"), stashP[0], stashP[1], result);
-    stashBusy = false;
-}
-void DCCEXParser::callback_Vbyte(int result)
-{
-    StringFormatter::send(stashStream, F("<v %d %d>"), stashP[0], result);
-    stashBusy = false;
+void DCCEXParser::commitAsyncReplyStream() {
+     if (stashRingStream) stashRingStream->commit();
+     stashBusy = false;
 }
 
-void DCCEXParser::callback_R(int result)
+void DCCEXParser::callback_W(int16_t result)
 {
-    StringFormatter::send(stashStream, F("<r%d|%d|%d %d>"), stashP[1], stashP[2], stashP[0], result);
-    stashBusy = false;
+    StringFormatter::send(getAsyncReplyStream(),
+          F("<r%d|%d|%d %d>\n"), stashP[2], stashP[3], stashP[0], result == 1 ? stashP[1] : -1);
+    commitAsyncReplyStream();
 }
 
-void DCCEXParser::callback_Rloco(int result)
+void DCCEXParser::callback_B(int16_t result)
 {
-    StringFormatter::send(stashStream, F("<r %d>"), result);
-    stashBusy = false;
+    StringFormatter::send(getAsyncReplyStream(), 
+          F("<r%d|%d|%d %d %d>\n"), stashP[3], stashP[4], stashP[0], stashP[1], result == 1 ? stashP[2] : -1);
+    commitAsyncReplyStream();
+}
+void DCCEXParser::callback_Vbit(int16_t result)
+{
+    StringFormatter::send(getAsyncReplyStream(), F("<v %d %d %d>\n"), stashP[0], stashP[1], result);
+    commitAsyncReplyStream();
+}
+void DCCEXParser::callback_Vbyte(int16_t result)
+{
+    StringFormatter::send(getAsyncReplyStream(), F("<v %d %d>\n"), stashP[0], result);
+    commitAsyncReplyStream();
+}
+
+void DCCEXParser::callback_R(int16_t result)
+{
+    StringFormatter::send(getAsyncReplyStream(), F("<r%d|%d|%d %d>\n"), stashP[1], stashP[2], stashP[0], result);
+    commitAsyncReplyStream();
+}
+
+void DCCEXParser::callback_Rloco(int16_t result)
+{
+    StringFormatter::send(getAsyncReplyStream(), F("<r %d>\n"), result);
+    commitAsyncReplyStream();
+}
+
+void DCCEXParser::callback_Wloco(int16_t result)
+{
+    if (result==1) result=stashP[0]; // pick up original requested id from command
+    StringFormatter::send(getAsyncReplyStream(), F("<w %d>\n"), result);
+    commitAsyncReplyStream();
 }

DCCEXParser.h

@@ -19,49 +19,60 @@
 #ifndef DCCEXParser_h
 #define DCCEXParser_h
 #include <Arduino.h>
+#include "FSH.h"
+#include "RingStream.h"
 
-typedef void (*FILTER_CALLBACK)(Print * stream, byte & opcode, byte & paramCount, int p[]);
+typedef void (*FILTER_CALLBACK)(Print * stream, byte & opcode, byte & paramCount, int16_t p[]);
 typedef void (*AT_COMMAND_CALLBACK)(const byte * command);
 
 struct DCCEXParser
 {
    DCCEXParser();
    void loop(Stream & stream);
-   void parse(Print * stream,  byte * command, bool blocking);
+   void parse(Print * stream,  byte * command,  RingStream * ringStream);
+   void parse(const FSH * cmd);
    void flush();
    static void setFilter(FILTER_CALLBACK filter);
+   static void setRMFTFilter(FILTER_CALLBACK filter);
    static void setAtCommandCallback(AT_COMMAND_CALLBACK filter);
-   static const int MAX_PARAMS=10;  // Must not exceed this
+   static const int MAX_COMMAND_PARAMS=10;  // Must not exceed this
  
    private:
   
-    static const int MAX_BUFFER=50;  // longest command sent in
+    static const int16_t MAX_BUFFER=50;  // longest command sent in
      byte  bufferLength=0;
      bool  inCommandPayload=false;
      byte  buffer[MAX_BUFFER+2]; 
-    int splitValues( int result[MAX_PARAMS], const byte * command);
+    int16_t splitValues( int16_t result[MAX_COMMAND_PARAMS], const byte * command);
+    int16_t splitHexValues( int16_t result[MAX_COMMAND_PARAMS], const byte * command);
      
-     bool parseT(Print * stream, int params, int p[]);
-     bool parseZ(Print * stream, int params, int p[]);
-     bool parseS(Print * stream,  int params, int p[]);
-     bool parsef(Print * stream,  int params, int p[]);
-     bool parseD(Print * stream,  int params, int p[]);
+     bool parseT(Print * stream, int16_t params, int16_t p[]);
+     bool parseZ(Print * stream, int16_t params, int16_t p[]);
+     bool parseS(Print * stream,  int16_t params, int16_t p[]);
+     bool parsef(Print * stream,  int16_t params, int16_t p[]);
+     bool parseD(Print * stream,  int16_t params, int16_t p[]);
+
+     static Print * getAsyncReplyStream();
+     static void commitAsyncReplyStream();
 
-    
     static bool stashBusy;
-   
+    static byte stashTarget;
     static Print * stashStream;
-    static int stashP[MAX_PARAMS];
-    bool stashCallback(Print * stream, int p[MAX_PARAMS]);
-    static void callback_W(int result);
-    static void callback_B(int result);        
-    static void callback_R(int result);
-    static void callback_Rloco(int result);
-    static void callback_Vbit(int result);
-    static void callback_Vbyte(int result);
+    static RingStream * stashRingStream;
+    
+    static int16_t stashP[MAX_COMMAND_PARAMS];
+    bool stashCallback(Print * stream, int16_t p[MAX_COMMAND_PARAMS], RingStream * ringStream);
+    static void callback_W(int16_t result);
+    static void callback_B(int16_t result);        
+    static void callback_R(int16_t result);
+    static void callback_Rloco(int16_t result);
+    static void callback_Wloco(int16_t result);
+    static void callback_Vbit(int16_t result);
+    static void callback_Vbyte(int16_t result);
     static FILTER_CALLBACK  filterCallback;
+    static FILTER_CALLBACK  filterRMFTCallback;
     static AT_COMMAND_CALLBACK  atCommandCallback;
-    static void funcmap(int cab, byte value, byte fstart, byte fstop);
+    static void funcmap(int16_t cab, byte value, byte fstart, byte fstop);
 
 };
 

DCCRMT.cpp

@@ -0,0 +1,168 @@
+/*
+ *  © 2021, Harald Barth.
+ *  
+ *  This file is part of DCC-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+#include "defines.h"
+#include "DIAG.h"
+#include "DCCRMT.h"
+#include "DCCWaveform.h" // for MAX_PACKET_SIZE
+
+#define DATA_LEN(X) ((X)*9+1) // Each byte has one bit extra and we have one EOF marker
+
+#if ESP_IDF_VERSION < ESP_IDF_VERSION_VAL(4,2,0)
+#error wrong IDF version
+#endif
+
+void setDCCBit1(rmt_item32_t* item) {
+  item->level0    = 1;
+  item->duration0 = DCC_1_HALFPERIOD;
+  item->level1    = 0;
+  item->duration1 = DCC_1_HALFPERIOD;
+}
+
+void setDCCBit0(rmt_item32_t* item) {
+  item->level0    = 1;
+  item->duration0 = DCC_0_HALFPERIOD;
+  item->level1    = 0;
+  item->duration1 = DCC_0_HALFPERIOD;
+}
+
+// special long zero to trigger scope
+void setDCCBit0Long(rmt_item32_t* item) {
+  item->level0    = 1;
+  item->duration0 = DCC_0_HALFPERIOD + DCC_0_HALFPERIOD/10;
+  item->level1    = 0;
+  item->duration1 = DCC_0_HALFPERIOD + DCC_0_HALFPERIOD/10;
+}
+
+void setEOT(rmt_item32_t* item) {
+  item->val = 0;
+}
+
+void IRAM_ATTR interrupt(rmt_channel_t channel, void *t) {
+  RMTPin *tt = (RMTPin *)t;
+  tt->RMTinterrupt();
+}
+
+RMTPin::RMTPin(byte pin, byte ch, byte plen) {
+
+  // preamble
+  preambleLen = plen+2; // plen 1 bits, one 0 bit and one EOF marker
+  preamble = (rmt_item32_t*)malloc(preambleLen*sizeof(rmt_item32_t));
+  for (byte n=0; n<plen; n++)
+    setDCCBit1(preamble + n);      // preamble bits
+#ifdef SCOPE
+  setDCCBit0Long(preamble + plen); // start of packet 0 bit long version
+#else
+  setDCCBit0(preamble + plen);     // start of packet 0 bit normal version
+#endif
+  setEOT(preamble + plen + 1);     // EOT marker
+
+  // idle
+  idleLen = 28;
+  idle = (rmt_item32_t*)malloc(idleLen*sizeof(rmt_item32_t));
+  for (byte n=0; n<8; n++)   // 0 to 7
+    setDCCBit1(idle + n);
+  for (byte n=8; n<18; n++)  // 8, 9 to 16, 17
+    setDCCBit0(idle + n);
+  for (byte n=18; n<26; n++) // 18 to 25
+    setDCCBit1(idle + n);
+  setDCCBit1(idle + 26);     // end bit
+  setEOT(idle + 27);         // EOT marker
+
+  // data: max packet size today is 5 + checksum
+  maxDataLen = DATA_LEN(MAX_PACKET_SIZE);
+  data = (rmt_item32_t*)malloc(maxDataLen*sizeof(rmt_item32_t));
+  
+  rmt_config_t config;
+  // Configure the RMT channel for TX
+  bzero(&config, sizeof(rmt_config_t));
+  config.rmt_mode = RMT_MODE_TX;
+  config.channel = channel = (rmt_channel_t)ch;
+  config.clk_div = RMT_CLOCK_DIVIDER;
+  config.gpio_num = (gpio_num_t)pin;
+  config.mem_block_num = 2; // With longest DCC packet 11 inc checksum (future expansion)
+                            // number of bits needed is 22preamble + start +
+                            // 11*9 + extrazero + EOT = 124
+                            // 2 mem block of 64 RMT items should be enough
+
+  ESP_ERROR_CHECK(rmt_config(&config));
+  // NOTE: ESP_INTR_FLAG_IRAM is *NOT* included in this bitmask
+  ESP_ERROR_CHECK(rmt_driver_install(config.channel, 0, ESP_INTR_FLAG_LOWMED|ESP_INTR_FLAG_SHARED));
+
+  DIAG(F("Register interrupt on core %d"), xPortGetCoreID());
+
+  ESP_ERROR_CHECK(rmt_set_tx_loop_mode(channel, true));
+  rmt_register_tx_end_callback(interrupt, this);
+  rmt_set_tx_intr_en(channel, true);
+
+  DIAG(F("Starting channel %d signal generator"), config.channel);
+
+  // send one bit to kickstart the signal, remaining data will come from the
+  // packet queue. We intentionally do not wait for the RMT TX complete here.
+  //rmt_write_items(channel, preamble, preambleLen, false);
+  RMTprefill();
+  preambleNext = true;
+  dataReady = false;
+  RMTinterrupt();
+}
+
+void RMTPin::RMTprefill() {
+  rmt_fill_tx_items(channel, preamble, preambleLen, 0);
+  rmt_fill_tx_items(channel, idle, idleLen, preambleLen-1);
+}
+
+const byte transmitMask[] = {0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01};
+
+bool RMTPin::RMTfillData(const byte buffer[], byte byteCount, byte repeatCount=1) {
+  if (dataReady == true || dataRepeat > 0) // we have still old work to do
+    return false;
+  if (DATA_LEN(byteCount) > maxDataLen)      // this would overun our allocated memory for data
+    return false;                      // something very broken, can not convert packet
+
+  // convert bytes to RMT stream of "bits"
+  byte bitcounter = 0;
+  for(byte n=0; n<byteCount; n++) {
+    for(byte bit=0; bit<8; bit++) {
+      if (buffer[n] & transmitMask[bit])
+	setDCCBit1(data + bitcounter++);
+      else
+	setDCCBit0(data + bitcounter++);
+    }
+    setDCCBit0(data + bitcounter++); // zero at end of each byte
+  }
+  setDCCBit1(data + bitcounter-1);     // overwrite previous zero bit with one bit
+  setEOT(data + bitcounter++);         // EOT marker
+  dataLen = bitcounter;
+  dataReady = true;
+  dataRepeat = repeatCount;
+  return true;
+}
+
+void IRAM_ATTR RMTPin::RMTinterrupt() {
+  //no rmt_tx_start(channel,true) as we run in loop mode
+  //preamble is always loaded at beginning of buffer
+  if (dataReady) {            // if we have new data, fill while preamble is running
+    rmt_fill_tx_items(channel, data, dataLen, preambleLen-1);
+    dataReady = false;
+  }
+  if (dataRepeat > 0)         // if a repeat count was specified, work on that
+    dataRepeat--;
+  return;
+}

DCCRMT.h

@@ -0,0 +1,57 @@
+/*
+ *  © 2021, Harald Barth.
+ *  
+ *  This file is part of DCC-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+#include <Arduino.h>
+#include "driver/rmt.h"
+#include "soc/rmt_reg.h"
+#include "soc/rmt_struct.h"
+
+// make calculations easy and set up for microseconds
+#define RMT_CLOCK_DIVIDER 80
+#define DCC_1_HALFPERIOD 58  //4640 // 1 / 80000000 * 4640 = 58us
+#define DCC_0_HALFPERIOD 100 //8000
+
+class RMTPin {
+ public:
+  RMTPin(byte pin, byte ch, byte plen);
+  void IRAM_ATTR RMTinterrupt();
+  void RMTprefill();
+  bool RMTfillData(const byte buffer[], byte byteCount, byte repeatCount);
+  
+  static RMTPin mainRMTPin;
+  static RMTPin progRMTPin;
+  
+ private:
+    
+  rmt_channel_t channel;
+  // 3 types of data to send, preamble and then idle or data
+  // if this is prog track, idle will contain reset instead
+  rmt_item32_t *idle;
+  byte idleLen;
+  rmt_item32_t *preamble;
+  byte preambleLen;
+  rmt_item32_t *data;
+  byte dataLen;
+  byte maxDataLen;
+  // flags 
+  volatile bool preambleNext = true;  // alternate between preamble and content
+  volatile bool dataReady = false;    // do we have real data available or send idle
+  volatile byte dataRepeat = 0;
+};

DCCTimer.cpp

@@ -0,0 +1,257 @@
+/*
+ *  © 2021, Chris Harlow & David Cutting. All rights reserved.
+ *  
+ *  This file is part of Asbelos DCC API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+
+/* This timer class is used to manage the single timer required to handle the DCC waveform.
+ *  All timer access comes through this class so that it can be compiled for 
+ *  various hardware CPU types. 
+ *  
+ *  DCCEX works on a single timer interrupt at a regular 58uS interval.
+ *  The DCCWaveform class generates the signals to the motor shield  
+ *  based on this timer. 
+ *  
+ *  If the motor drivers are BOTH configured to use the correct 2 pins for the architecture,
+ *  (see isPWMPin() function. )
+ *  then this allows us to use a hardware driven pin switching arrangement which is
+ *  achieved by setting the duty cycle of the NEXT clock interrupt to 0% or 100% depending on 
+ *  the required pin state. (see setPWM())  
+ *  This is more accurate than the software interrupt but at the expense of 
+ *  limiting the choice of available pins. 
+ *  Fortunately, a standard motor shield on a Mega uses pins that qualify for PWM... 
+ *  Other shields may be jumpered to PWM pins or run directly using the software interrupt.
+ *  
+ *  Because the PWM-based waveform is effectively set half a cycle after the software version,
+ *  it is not acceptable to drive the two tracks on different methiods or it would cause
+ *  problems for <1 JOIN> etc.
+ *  
+ */
+
+#include "DCCTimer.h"
+const int DCC_SIGNAL_TIME=58;  // this is the 58uS DCC 1-bit waveform half-cycle 
+const long CLOCK_CYCLES=(F_CPU / 1000000 * DCC_SIGNAL_TIME);
+
+INTERRUPT_CALLBACK interruptHandler=0;
+
+#ifdef ARDUINO_ARCH_MEGAAVR
+  // Arduino unoWifi Rev2 and nanoEvery architectire 
+  
+  void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
+    interruptHandler=callback;
+    noInterrupts();
+    ADC0.CTRLC = (ADC0.CTRLC & 0b00110000) | 0b01000011;  // speed up analogRead sample time   
+    TCB0.CTRLB = TCB_CNTMODE_INT_gc & ~TCB_CCMPEN_bm; // timer compare mode with output disabled
+    TCB0.CTRLA = TCB_CLKSEL_CLKDIV2_gc; //   8 MHz ~ 0.125 us      
+    TCB0.CCMP =  (CLOCK_CYCLES>>1) -1;  // 1 tick less for timer reset
+    TCB0.INTFLAGS = TCB_CAPT_bm; // clear interrupt request flag
+    TCB0.INTCTRL = TCB_CAPT_bm;  // Enable the interrupt
+    TCB0.CNT = 0;
+    TCB0.CTRLA |= TCB_ENABLE_bm;  // start
+    interrupts();
+  }
+
+  // ISR called by timer interrupt every 58uS
+  ISR(TCB0_INT_vect){
+    TCB0.INTFLAGS = TCB_CAPT_bm;
+    interruptHandler();
+  }
+
+  bool DCCTimer::isPWMPin(byte pin) {
+       (void) pin; 
+       return false;  // TODO what are the relevant pins? 
+  }
+
+ void DCCTimer::setPWM(byte pin, bool high) {
+    (void) pin;
+    (void) high;
+    // TODO what are the relevant pins?
+ }
+
+  void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+    memcpy(mac,(void *) &SIGROW.SERNUM0,6);  // serial number
+    mac[0] &= 0xFE;
+    mac[0] |= 0x02;
+  }
+
+#elif defined(TEENSYDUINO)
+  IntervalTimer myDCCTimer;
+
+  void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
+    interruptHandler=callback;
+
+  myDCCTimer.begin(interruptHandler, DCC_SIGNAL_TIME);
+
+  }
+
+  bool DCCTimer::isPWMPin(byte pin) {
+       //Teensy: digitalPinHasPWM, todo
+      (void) pin;
+       return false;  // TODO what are the relevant pins? 
+  }
+
+ void DCCTimer::setPWM(byte pin, bool high) {
+    // TODO what are the relevant pins?
+    (void) pin;
+    (void) high;
+}
+
+  void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+#if defined(__IMXRT1062__)  //Teensy 4.0 and Teensy 4.1
+    uint32_t m1 = HW_OCOTP_MAC1;
+    uint32_t m2 = HW_OCOTP_MAC0;
+    mac[0] = m1 >> 8;
+    mac[1] = m1 >> 0;
+    mac[2] = m2 >> 24;
+    mac[3] = m2 >> 16;
+    mac[4] = m2 >> 8;
+    mac[5] = m2 >> 0;
+#else
+    read_mac(mac);
+#endif
+  }
+
+#if !defined(__IMXRT1062__)
+  void DCCTimer::read_mac(byte mac[6]) {
+    read(0xe,mac,0);
+    read(0xf,mac,3);
+  }
+
+// http://forum.pjrc.com/threads/91-teensy-3-MAC-address
+void DCCTimer::read(uint8_t word, uint8_t *mac, uint8_t offset) {
+  FTFL_FCCOB0 = 0x41;             // Selects the READONCE command
+  FTFL_FCCOB1 = word;             // read the given word of read once area
+
+  // launch command and wait until complete
+  FTFL_FSTAT = FTFL_FSTAT_CCIF;
+  while(!(FTFL_FSTAT & FTFL_FSTAT_CCIF));
+
+  *(mac+offset) =   FTFL_FCCOB5;       // collect only the top three bytes,
+  *(mac+offset+1) = FTFL_FCCOB6;       // in the right orientation (big endian).
+  *(mac+offset+2) = FTFL_FCCOB7;       // Skip FTFL_FCCOB4 as it's always 0.
+}
+#endif
+
+#elif defined(ARDUINO_ARCH_ESP8266)
+
+void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
+  interruptHandler=callback;
+  timer1_disable();
+
+  // There seem to be differnt ways to attach interrupt handler
+  //    ETS_FRC_TIMER1_INTR_ATTACH(NULL, NULL);
+  //    ETS_FRC_TIMER1_NMI_INTR_ATTACH(interruptHandler);
+  // Let us choose the one from the API
+  timer1_attachInterrupt(interruptHandler);
+
+  // not exactly sure of order:
+  timer1_enable(TIM_DIV1, TIM_EDGE, TIM_LOOP);
+  timer1_write(CLOCK_CYCLES);
+}
+// We do not support to use PWM to make the Waveform on ESP
+bool IRAM_ATTR DCCTimer::isPWMPin(byte pin) {
+  return false;
+}
+void IRAM_ATTR DCCTimer::setPWM(byte pin, bool high) {
+}
+
+#elif defined(ARDUINO_ARCH_ESP32)
+// https://www.visualmicro.com/page/Timer-Interrupts-Explained.aspx
+
+portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED;
+
+void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
+  interruptHandler = callback;
+  hw_timer_t *timer = NULL;
+  timer = timerBegin(0, 2, true); // prescaler can be 2 to 65536 so choose 2
+  timerAttachInterrupt(timer, interruptHandler, true);
+  timerAlarmWrite(timer, CLOCK_CYCLES / 6, true); // divide by prescaler*3 (Clockbase is 80Mhz and not F_CPU 240Mhz)
+  timerAlarmEnable(timer);
+}
+
+// We do not support to use PWM to make the Waveform on ESP
+bool IRAM_ATTR DCCTimer::isPWMPin(byte pin) {
+  return false;
+}
+void IRAM_ATTR DCCTimer::setPWM(byte pin, bool high) {
+}
+
+#else 
+  // Arduino nano, uno, mega etc
+#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+    #define TIMER1_A_PIN   11
+    #define TIMER1_B_PIN   12
+    #define TIMER1_C_PIN   13
+#else
+   #define TIMER1_A_PIN   9
+   #define TIMER1_B_PIN   10
+#endif
+
+  void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
+    interruptHandler=callback;
+    noInterrupts();
+    ADCSRA = (ADCSRA & 0b11111000) | 0b00000100;   // speed up analogRead sample time 
+    TCCR1A = 0;
+    ICR1 = CLOCK_CYCLES>>1;
+    TCNT1 = 0;   
+    TCCR1B = _BV(WGM13) | _BV(CS10);     // Mode 8, clock select 1
+    TIMSK1 = _BV(TOIE1); // Enable Software interrupt
+    interrupts();
+  }
+
+// ISR called by timer interrupt every 58uS
+  ISR(TIMER1_OVF_vect){ interruptHandler(); }
+
+// Alternative pin manipulation via PWM control.
+  bool DCCTimer::isPWMPin(byte pin) {
+       return pin==TIMER1_A_PIN 
+           || pin==TIMER1_B_PIN
+       #ifdef TIMER1_C_PIN 
+           || pin==TIMER1_C_PIN
+       #endif       
+       ;
+  }
+
+ void DCCTimer::setPWM(byte pin, bool high) {
+    if (pin==TIMER1_A_PIN) {
+      TCCR1A |= _BV(COM1A1);
+      OCR1A= high?1024:0;
+    }
+    else if (pin==TIMER1_B_PIN) { 
+      TCCR1A |= _BV(COM1B1);
+      OCR1B= high?1024:0;
+    }
+ #ifdef TIMER1_C_PIN 
+    else if (pin==TIMER1_C_PIN) { 
+      TCCR1A |= _BV(COM1C1);
+      OCR1C= high?1024:0;
+    }
+ #endif       
+ }
+
+
+  #include <avr/boot.h> 
+  void DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+    for (byte i=0; i<6; i++) {
+      mac[i]=boot_signature_byte_get(0x0E + i);
+    }
+    mac[0] &= 0xFE;
+    mac[0] |= 0x02;
+
+  }
+
+#endif

DCCTimer.h

@@ -0,0 +1,50 @@
+/*
+ *  (c) 2021 Mike S. All rights reserved.
+ *  (c) 2021 Fred Decker.  All rights reserved.
+ *  
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef DCCTimer_h
+#define DCCTimer_h
+#include "Arduino.h"
+
+typedef void (*INTERRUPT_CALLBACK)();
+
+class DCCTimer {
+  public:
+  static void begin(INTERRUPT_CALLBACK interrupt);
+  static void getSimulatedMacAddress(byte mac[6]);
+  static bool isPWMPin(byte pin);
+  static void setPWM(byte pin, bool high);
+#if (defined(TEENSYDUINO) && !defined(__IMXRT1062__))
+  static void read_mac(byte mac[6]);
+  static void read(uint8_t word, uint8_t *mac, uint8_t offset);
+#endif
+  private:
+};
+
+#if defined(ARDUINO_ARCH_ESP32)
+extern portMUX_TYPE timerMux;
+#endif
+
+#if !(defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_ARCH_ESP8266))
+#ifndef IRAM_ATTR
+#define IRAM_ATTR
+#endif
+#endif
+
+#endif //DCCTimer.h

DCCWaveform.cpp

@@ -17,69 +17,103 @@
  *  You should have received a copy of the GNU General Public License
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
+
 #include <Arduino.h>
 
+#include "defines.h"
 #include "DCCWaveform.h"
+#include "DCCTimer.h"
 #include "DIAG.h"
- 
-const int NORMAL_SIGNAL_TIME=58;  // this is the 58uS DCC 1-bit waveform half-cycle 
-const int SLOW_SIGNAL_TIME=NORMAL_SIGNAL_TIME*512;
+#include "freeMemory.h"
 
 DCCWaveform  DCCWaveform::mainTrack(PREAMBLE_BITS_MAIN, true);
 DCCWaveform  DCCWaveform::progTrack(PREAMBLE_BITS_PROG, false);
 
-
 bool DCCWaveform::progTrackSyncMain=false; 
 bool DCCWaveform::progTrackBoosted=false; 
-VirtualTimer * DCCWaveform::interruptTimer=NULL;      
-  
-void DCCWaveform::begin(MotorDriver * mainDriver, MotorDriver * progDriver, byte timerNumber) {
+int  DCCWaveform::progTripValue=0;
+volatile uint8_t DCCWaveform::numAckGaps=0;
+volatile uint8_t DCCWaveform::numAckSamples=0;
+uint8_t DCCWaveform::trailingEdgeCounter=0;
+
+void DCCWaveform::begin(MotorDriver * mainDriver, MotorDriver * progDriver) {
+
+  mainTrack.rmtPin = new RMTPin(21, 0, PREAMBLE_BITS_MAIN);
+
   mainTrack.motorDriver=mainDriver;
   progTrack.motorDriver=progDriver;
-
+  progTripValue = progDriver->mA2raw(TRIP_CURRENT_PROG); // need only calculate once hence static
   mainTrack.setPowerMode(POWERMODE::OFF);      
   progTrack.setPowerMode(POWERMODE::OFF);
-  switch (timerNumber) {
-    case 1: interruptTimer= &TimerA; break;
-    case 2: interruptTimer= &TimerB; break;
-#ifndef ARDUINO_AVR_UNO  
-    case 3: interruptTimer= &TimerC; break;
-#endif    
-    default:
-      DIAG(F("\n\n *** Invalid Timer number %d requested. Only 1..3 valid.  DCC will not work.*** \n\n"), timerNumber);
-      return;
+  // Fault pin config for odd motor boards (example pololu)
+  MotorDriver::commonFaultPin = ((mainDriver->getFaultPin() == progDriver->getFaultPin())
+				 && (mainDriver->getFaultPin() != UNUSED_PIN));
+  // Only use PWM if both pins are PWM capable. Otherwise JOIN does not work
+  MotorDriver::usePWM= mainDriver->isPWMCapable() && progDriver->isPWMCapable();
+  DIAG(F("Signal pin config: %S accuracy waveform"),
+	 MotorDriver::usePWM ? F("high") : F("normal") );
+  DCCTimer::begin(DCCWaveform::interruptHandler);     
+}
+
+#ifdef SLOW_ANALOG_READ
+// Flag to hold if we need to run ack checking in loop
+volatile bool ackflag = 0;
+#endif
+
+void IRAM_ATTR DCCWaveform::loop(bool ackManagerActive) {
+
+  if (mainTrack.packetPendingRMT) {
+    mainTrack.rmtPin->RMTfillData(mainTrack.pendingPacket, mainTrack.pendingLength, mainTrack.pendingRepeats);
+    mainTrack.packetPendingRMT=false;
+    // sentResetsSincePacket = 0 // later when progtrack
   }
-  interruptTimer->initialize();
-  interruptTimer->setPeriod(NORMAL_SIGNAL_TIME); // this is the 58uS DCC 1-bit waveform half-cycle
-  interruptTimer->attachInterrupt(interruptHandler);
-  interruptTimer->start();
-}
-void DCCWaveform::setDiagnosticSlowWave(bool slow) {
-  interruptTimer->setPeriod(slow? SLOW_SIGNAL_TIME : NORMAL_SIGNAL_TIME);
-  interruptTimer->start(); 
-  DIAG(F("\nDCC SLOW WAVE %S\n"),slow?F("SET. DO NOT ADD LOCOS TO TRACK"):F("RESET")); 
+
+#ifdef SLOW_ANALOG_READ
+  if (ackflag) {
+    progTrack.checkAck();
+    // reset flag AFTER check is done
+    portENTER_CRITICAL(&timerMux);
+    ackflag = 0;
+    portEXIT_CRITICAL(&timerMux);
+  } else {
+    progTrack.checkPowerOverload(ackManagerActive);
+  }
+#else
+  progTrack.checkPowerOverload(ackManagerActive);
+#endif
+  mainTrack.checkPowerOverload(false);
 }
 
-void DCCWaveform::loop() {
-  mainTrack.checkPowerOverload();
-  progTrack.checkPowerOverload();
-}
-
-
-// static //
-void DCCWaveform::interruptHandler() {
+#pragma GCC push_options
+#pragma GCC optimize ("-O3")
+void IRAM_ATTR DCCWaveform::interruptHandler() {
   // call the timer edge sensitive actions for progtrack and maintrack
-  bool mainCall2 = mainTrack.interrupt1();
-  bool progCall2 = progTrack.interrupt1();
-
-  // call (if necessary) the procs to get the current bits
-  // these must complete within 50microsecs of the interrupt
-  // but they are only called ONCE PER BIT TRANSMITTED
-  // after the rising edge of the signal
-  if (mainCall2) mainTrack.interrupt2();
-  if (progCall2) progTrack.interrupt2();
+  // member functions would be cleaner but have more overhead
+  byte sigMain=signalTransform[mainTrack.state];
+  byte sigProg=progTrackSyncMain? sigMain : signalTransform[progTrack.state];
+  // Set the signal state for both tracks
+  mainTrack.motorDriver->setSignal(sigMain);
+  progTrack.motorDriver->setSignal(sigProg);
+  // Move on in the state engine
+  mainTrack.state=stateTransform[mainTrack.state];    
+  progTrack.state=stateTransform[progTrack.state];    
+  // WAVE_PENDING means we dont yet know what the next bit is
+  if (mainTrack.state==WAVE_PENDING)
+    mainTrack.interrupt2();
+  if (progTrack.state==WAVE_PENDING)
+    progTrack.interrupt2();
+#ifdef SLOW_ANALOG_READ
+  else if (progTrack.ackPending && ackflag == 0) { // We need AND we are not already checking
+    portENTER_CRITICAL(&timerMux);
+    ackflag = 1;
+    portEXIT_CRITICAL(&timerMux);
+  }
+#else
+  else if (progTrack.ackPending)
+    progTrack.checkAck();
+#endif
 }
-
+#pragma GCC push_options
 
 // An instance of this class handles the DCC transmissions for one track. (main or prog)
 // Interrupts are marshalled via the statics.
@@ -92,13 +126,13 @@ const byte bitMask[] = {0x00, 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01};
 
 
 DCCWaveform::DCCWaveform( byte preambleBits, bool isMain) {
-  // establish appropriate pins
   isMainTrack = isMain;
   packetPending = false;
+  packetPendingRMT = false;
   memcpy(transmitPacket, idlePacket, sizeof(idlePacket));
-  state = 0;
+  state = WAVE_START;
   // The +1 below is to allow the preamble generator to create the stop bit
-  // fpr the previous packet. 
+  // for the previous packet. 
   requiredPreambles = preambleBits+1;  
   bytes_sent = 0;
   bits_sent = 0;
@@ -112,34 +146,48 @@ POWERMODE DCCWaveform::getPowerMode() {
 }
 
 void DCCWaveform::setPowerMode(POWERMODE mode) {
-
-  // Prevent power switch on with no timer... Otheruise track will get full power DC and locos will run away.  
-  if (!interruptTimer) return; 
-  
   powerMode = mode;
   bool ison = (mode == POWERMODE::ON);
   motorDriver->setPower( ison);
+  sentResetsSincePacket=0; 
 }
 
 
-void DCCWaveform::checkPowerOverload() {
-  
-  static int progTripValue = motorDriver->mA2raw(TRIP_CURRENT_PROG); // need only calculate once, hence static
-
+void DCCWaveform::checkPowerOverload(bool ackManagerActive) {
   if (millis() - lastSampleTaken  < sampleDelay) return;
   lastSampleTaken = millis();
   int tripValue= motorDriver->getRawCurrentTripValue();
-  if (!isMainTrack && !ackPending && !progTrackSyncMain && !progTrackBoosted)
+  if (!isMainTrack && !ackManagerActive && !progTrackSyncMain && !progTrackBoosted)
     tripValue=progTripValue;
   
+  // Trackname for diag messages later
+  const FSH*trackname = isMainTrack ? F("MAIN") : F("PROG");
   switch (powerMode) {
     case POWERMODE::OFF:
       sampleDelay = POWER_SAMPLE_OFF_WAIT;
       break;
     case POWERMODE::ON:
       // Check current
-      lastCurrent = motorDriver->getCurrentRaw();
-      if (lastCurrent <= tripValue) {
+      lastCurrent=motorDriver->getCurrentRaw();
+      if (lastCurrent < 0) {
+	  // We have a fault pin condition to take care of
+	  lastCurrent = -lastCurrent;
+	  setPowerMode(POWERMODE::OVERLOAD); // Turn off, decide later how fast to turn on again
+	  if (MotorDriver::commonFaultPin) {
+	      if (lastCurrent <= tripValue) {
+		setPowerMode(POWERMODE::ON); // maybe other track
+	      }
+	      // Write this after the fact as we want to turn on as fast as possible
+	      // because we don't know which output actually triggered the fault pin
+	      DIAG(F("COMMON FAULT PIN ACTIVE - TOGGLED POWER on %S"), trackname);
+	  } else {
+	    DIAG(F("%S FAULT PIN ACTIVE - OVERLOAD"), trackname);
+	      if (lastCurrent < tripValue) {
+		  lastCurrent = tripValue; // exaggerate
+	      }
+	  }
+      }
+      if (lastCurrent < tripValue) {
         sampleDelay = POWER_SAMPLE_ON_WAIT;
 	if(power_good_counter<100)
 	  power_good_counter++;
@@ -149,9 +197,9 @@ void DCCWaveform::checkPowerOverload() {
         setPowerMode(POWERMODE::OVERLOAD);
         unsigned int mA=motorDriver->raw2mA(lastCurrent);
         unsigned int maxmA=motorDriver->raw2mA(tripValue);
-        DIAG(F("\n*** %S TRACK POWER OVERLOAD current=%d max=%d  offtime=%l ***\n"), isMainTrack ? F("MAIN") : F("PROG"), mA, maxmA, power_sample_overload_wait);
 	power_good_counter=0;
         sampleDelay = power_sample_overload_wait;
+        DIAG(F("%S TRACK POWER OVERLOAD current=%d max=%d offtime=%d"), trackname, mA, maxmA, sampleDelay);
 	if (power_sample_overload_wait >= 10000)
 	    power_sample_overload_wait = 10000;
 	else
@@ -162,73 +210,52 @@ void DCCWaveform::checkPowerOverload() {
       // Try setting it back on after the OVERLOAD_WAIT
       setPowerMode(POWERMODE::ON);
       sampleDelay = POWER_SAMPLE_ON_WAIT;
+      // Debug code....
+      DIAG(F("%S TRACK POWER RESET delay=%d"), trackname, sampleDelay);
       break;
     default:
       sampleDelay = 999; // cant get here..meaningless statement to avoid compiler warning.
   }
 }
+// For each state of the wave  nextState=stateTransform[currentState] 
+const WAVE_STATE DCCWaveform::stateTransform[]={
+   /* WAVE_START   -> */ WAVE_PENDING,
+   /* WAVE_MID_1   -> */ WAVE_START,
+   /* WAVE_HIGH_0  -> */ WAVE_MID_0,
+   /* WAVE_MID_0   -> */ WAVE_LOW_0,
+   /* WAVE_LOW_0   -> */ WAVE_START,
+   /* WAVE_PENDING (should not happen) -> */ WAVE_PENDING};
 
-
-
-
-
-// process time-edge sensitive part of interrupt
-// return true if second level required
-bool DCCWaveform::interrupt1() {
-  // NOTE: this must consume transmission buffers even if the power is off
-  // otherwise can cause hangs in main loop waiting for the pendingBuffer.
-  switch (state) {
-    case 0:  // start of bit transmission
-      setSignal(HIGH);
-      state = 1;
-      return true; // must call interrupt2 to set currentBit
-
-    case 1:  // 58us after case 0
-      if (currentBit) {
-        setSignal(LOW);
-        state = 0;
-      }
-      else state = 2;
-      break;
-    case 2:  // 116us after case 0
-      setSignal(LOW);
-      state = 3;
-      break;
-    case 3:  // finished sending zero bit
-      state = 0;
-      break;
-  }
-
-  // ACK check is prog track only and will only be checked if 
-  // this is not case(0) which needs  relatively expensive packet change code to be called.
-  if (ackPending) checkAck();
-
-  return false;
-
-}
-
-void DCCWaveform::setSignal(bool high) {
-  if (progTrackSyncMain) {
-    if (!isMainTrack) return; // ignore PROG track waveform while in sync
-    // set both tracks to same signal
-    motorDriver->setSignal(high);
-    progTrack.motorDriver->setSignal(high);
-    return;     
-  }
-  motorDriver->setSignal(high);
-}
-      
-void DCCWaveform::interrupt2() {
-  // set currentBit to be the next bit to be sent.
+// For each state of the wave, signal pin is HIGH or LOW   
+const bool DCCWaveform::signalTransform[]={
+   /* WAVE_START   -> */ HIGH,
+   /* WAVE_MID_1   -> */ LOW,
+   /* WAVE_HIGH_0  -> */ HIGH,
+   /* WAVE_MID_0   -> */ LOW,
+   /* WAVE_LOW_0   -> */ LOW,
+   /* WAVE_PENDING (should not happen) -> */ LOW};
+        
+#pragma GCC push_options
+#pragma GCC optimize ("-O3")
+void IRAM_ATTR DCCWaveform::interrupt2() {
+  // calculate the next bit to be sent:
+  // set state WAVE_MID_1  for a 1=bit
+  //        or WAVE_HIGH_0 for a 0 bit.
 
   if (remainingPreambles > 0 ) {
-    currentBit = true;
+    state=WAVE_MID_1;  // switch state to trigger LOW on next interrupt
     remainingPreambles--;
+    // Update free memory diagnostic as we don't have anything else to do this time.
+    // Allow for checkAck and its called functions using 22 bytes more.
+#ifndef ESP_FAMILY
+    updateMinimumFreeMemory(22);
+#endif
     return;
   }
 
+  // Wave has gone HIGH but what happens next depends on the bit to be transmitted
   // beware OF 9-BIT MASK  generating a zero to start each byte
-  currentBit = transmitPacket[bytes_sent] & bitMask[bits_sent];
+  state=(transmitPacket[bytes_sent] & bitMask[bits_sent])? WAVE_MID_1 : WAVE_HIGH_0; 
   bits_sent++;
 
   // If this is the last bit of a byte, prepare for the next byte
@@ -247,12 +274,17 @@ void DCCWaveform::interrupt2() {
         transmitRepeats--;
       }
       else if (packetPending) {
-        // Copy pending packet to transmit packet
-        for (int b = 0; b < pendingLength; b++) transmitPacket[b] = pendingPacket[b];
+	portENTER_CRITICAL(&timerMux);
+	// Copy pending packet to transmit packet
+        // a fixed length memcpy is faster than a variable length loop for these small lengths
+        // for (int b = 0; b < pendingLength; b++) transmitPacket[b] = pendingPacket[b];
+        memcpy( transmitPacket, pendingPacket, sizeof(pendingPacket));
+        
         transmitLength = pendingLength;
         transmitRepeats = pendingRepeats;
         packetPending = false;
         sentResetsSincePacket=0;
+	portEXIT_CRITICAL(&timerMux);
       }
       else {
         // Fortunately reset and idle packets are the same length
@@ -264,28 +296,27 @@ void DCCWaveform::interrupt2() {
     }
   }  
 }
-
+#pragma GCC pop_options
 
 
 // Wait until there is no packet pending, then make this pending
 void DCCWaveform::schedulePacket(const byte buffer[], byte byteCount, byte repeats) {
-  if (byteCount >= MAX_PACKET_SIZE) return; // allow for chksum
+  if (byteCount > MAX_PACKET_SIZE) return; // allow for chksum
   while (packetPending);
-
+  portENTER_CRITICAL(&timerMux);
   byte checksum = 0;
-  for (int b = 0; b < byteCount; b++) {
+  for (byte b = 0; b < byteCount; b++) {
     checksum ^= buffer[b];
     pendingPacket[b] = buffer[b];
   }
+  // buffer is MAX_PACKET_SIZE but pendingPacket is one bigger
   pendingPacket[byteCount] = checksum;
   pendingLength = byteCount + 1;
   pendingRepeats = repeats;
   packetPending = true;
+  packetPendingRMT = true;
   sentResetsSincePacket=0;
-}
-
-int DCCWaveform::getLastCurrent() {
-   return lastCurrent;
+  portEXIT_CRITICAL(&timerMux);
 }
 
 // Operations applicable to PROG track ONLY.
@@ -293,11 +324,12 @@ int DCCWaveform::getLastCurrent() {
 
 void DCCWaveform::setAckBaseline() {
       if (isMainTrack) return;
-      int baseline = motorDriver->getCurrentRaw();
+      int baseline=motorDriver->getCurrentRaw();
       ackThreshold= baseline + motorDriver->mA2raw(ackLimitmA);
-      if (Diag::ACK) DIAG(F("\nACK baseline=%d/%dmA threshold=%d/%dmA"),
+      if (Diag::ACK) DIAG(F("ACK baseline=%d/%dmA Threshold=%d/%dmA Duration between %dus and %dus"),
 			  baseline,motorDriver->raw2mA(baseline),
-			  ackThreshold,motorDriver->raw2mA(ackThreshold));
+			  ackThreshold,motorDriver->raw2mA(ackThreshold),
+                          minAckPulseDuration, maxAckPulseDuration);
 }
 
 void DCCWaveform::setAckPending() {
@@ -307,31 +339,39 @@ void DCCWaveform::setAckPending() {
       ackPulseDuration=0;
       ackDetected=false;
       ackCheckStart=millis();
+      numAckSamples=0;
+      numAckGaps=0;
       ackPending=true;  // interrupt routines will now take note
 }
 
 byte DCCWaveform::getAck() {
       if (ackPending) return (2);  // still waiting
-      if (Diag::ACK) DIAG(F("\nACK-%S after %dmS max=%d/%dmA pulse=%duS"),ackDetected?F("OK"):F("FAIL"), ackCheckDuration, 
-           ackMaxCurrent,motorDriver->raw2mA(ackMaxCurrent), ackPulseDuration);
+      if (Diag::ACK) DIAG(F("%S after %dmS max=%d/%dmA pulse=%duS samples=%d gaps=%d"),ackDetected?F("ACK"):F("NO-ACK"), ackCheckDuration,
+			  ackMaxCurrent,motorDriver->raw2mA(ackMaxCurrent), ackPulseDuration, numAckSamples, numAckGaps);
       if (ackDetected) return (1); // Yes we had an ack
       return(0);  // pending set off but not detected means no ACK.   
 }
 
-void DCCWaveform::checkAck() {
+#pragma GCC push_options
+#pragma GCC optimize ("-O3")
+void IRAM_ATTR DCCWaveform::checkAck() {
     // This function operates in interrupt() time so must be fast and can't DIAG 
-    
     if (sentResetsSincePacket > 6) {  //ACK timeout
         ackCheckDuration=millis()-ackCheckStart;
         ackPending = false;
         return; 
     }
-      
-    lastCurrent=motorDriver->getCurrentRaw();
-    if (lastCurrent > ackMaxCurrent) ackMaxCurrent=lastCurrent;
-    // An ACK is a pulse lasting between MIN_ACK_PULSE_DURATION and MAX_ACK_PULSE_DURATION uSecs (refer @haba)
+
+    int current=motorDriver->getCurrentRaw();
+    numAckSamples++;
+    if (current > ackMaxCurrent) ackMaxCurrent=current;
+    // An ACK is a pulse lasting between minAckPulseDuration and maxAckPulseDuration uSecs (refer @haba)
         
-    if (lastCurrent>ackThreshold) {
+    if (current>ackThreshold) {
+       if (trailingEdgeCounter > 0) {
+	 numAckGaps++;
+	 trailingEdgeCounter = 0;
+       }
        if (ackPulseStart==0) ackPulseStart=micros();    // leading edge of pulse detected
        return;
     }
@@ -339,10 +379,22 @@ void DCCWaveform::checkAck() {
     // not in pulse
     if (ackPulseStart==0) return; // keep waiting for leading edge 
     
+    // if we reach to this point, we have
     // detected trailing edge of pulse
-    ackPulseDuration=micros()-ackPulseStart;
-               
-    if (ackPulseDuration>=MIN_ACK_PULSE_DURATION && ackPulseDuration<=MAX_ACK_PULSE_DURATION) {
+    if (trailingEdgeCounter == 0) {
+      ackPulseDuration=micros()-ackPulseStart;
+    }
+
+    // but we do not trust it yet and return (which will force another
+    // measurement) and first the third time around with low current
+    // the ack detection will be finalized. 
+    if (trailingEdgeCounter < 2) {
+      trailingEdgeCounter++;
+      return;
+    }
+    trailingEdgeCounter = 0;
+
+    if (ackPulseDuration>=minAckPulseDuration && ackPulseDuration<=maxAckPulseDuration) {
         ackCheckDuration=millis()-ackCheckStart;
         ackDetected=true;
         ackPending=false;
@@ -351,3 +403,4 @@ void DCCWaveform::checkAck() {
     }      
     ackPulseStart=0;  // We have detected a too-short or too-long pulse so ignore and wait for next leading edge 
 }
+#pragma GCC pop_options

DCCWaveform.h

@@ -19,30 +19,30 @@
  */
 #ifndef DCCWaveform_h
 #define DCCWaveform_h
+
+#include "DCCRMT.h"
 #include "MotorDriver.h"
-#include "ArduinoTimers.h"
 
 // Wait times for power management. Unit: milliseconds
 const int  POWER_SAMPLE_ON_WAIT = 100;
 const int  POWER_SAMPLE_OFF_WAIT = 1000;
 const int  POWER_SAMPLE_OVERLOAD_WAIT = 20;
 
-// Ack time thresholds. Unit: microseconds
-const int  MIN_ACK_PULSE_DURATION = 2000;
-const int  MAX_ACK_PULSE_DURATION = 8500;
- 
 // Number of preamble bits.
 const int   PREAMBLE_BITS_MAIN = 16;
 const int   PREAMBLE_BITS_PROG = 22;
+const byte   MAX_PACKET_SIZE = 5;  // NMRA standard extended packets, payload size WITHOUT checksum.
+
+// The WAVE_STATE enum is deliberately numbered because a change of order would be catastrophic
+// to the transform array.
+enum  WAVE_STATE : byte {WAVE_START=0,WAVE_MID_1=1,WAVE_HIGH_0=2,WAVE_MID_0=3,WAVE_LOW_0=4,WAVE_PENDING=5};
 
 
-
-const byte   MAX_PACKET_SIZE = 12;
 // NOTE: static functions are used for the overall controller, then
 // one instance is created for each track.
 
 
-enum class POWERMODE { OFF, ON, OVERLOAD };
+enum class POWERMODE : byte { OFF, ON, OVERLOAD };
 
 const byte idlePacket[] = {0xFF, 0x00, 0xFF};
 const byte resetPacket[] = {0x00, 0x00, 0x00};
@@ -50,19 +50,40 @@ const byte resetPacket[] = {0x00, 0x00, 0x00};
 class DCCWaveform {
   public:
     DCCWaveform( byte preambleBits, bool isMain);
-    static void begin(MotorDriver * mainDriver, MotorDriver * progDriver, byte timerNumber);
-    static void setDiagnosticSlowWave(bool slow);
-    static void loop();
+    static void begin(MotorDriver * mainDriver, MotorDriver * progDriver);
+    static void loop(bool ackManagerActive);
     static DCCWaveform  mainTrack;
     static DCCWaveform  progTrack;
 
     void beginTrack();
     void setPowerMode(POWERMODE);
     POWERMODE getPowerMode();
-    void checkPowerOverload();
-    int  getLastCurrent();
+    void checkPowerOverload(bool ackManagerActive);
+    inline int get1024Current() {
+	  if (powerMode == POWERMODE::ON)
+	      return (int)(lastCurrent*(long int)1024/motorDriver->getRawCurrentTripValue());
+	  return 0;
+    }
+    inline int getCurrentmA() {
+      if (powerMode == POWERMODE::ON)
+        return motorDriver->raw2mA(lastCurrent);
+      return 0;
+    }
+    inline int getMaxmA() {
+      if (maxmA == 0) { //only calculate this for first request, it doesn't change
+        maxmA = motorDriver->raw2mA(motorDriver->getRawCurrentTripValue()); //TODO: replace with actual max value or calc
+      }
+      return maxmA;        
+    }
+    inline int getTripmA() { 
+      if (tripmA == 0) { //only calculate this for first request, it doesn't change
+        tripmA = motorDriver->raw2mA(motorDriver->getRawCurrentTripValue());
+      }
+      return tripmA;        
+    }
     void schedulePacket(const byte buffer[], byte byteCount, byte repeats);
     volatile bool packetPending;
+    volatile bool packetPendingRMT;
     volatile byte sentResetsSincePacket;
     volatile bool autoPowerOff=false;
     void setAckBaseline();  //prog track only
@@ -76,36 +97,50 @@ class DCCWaveform {
 	    autoPowerOff=false;
 	}
     };
+    inline bool canMeasureCurrent() {
+      return motorDriver->canMeasureCurrent();
+    };
     inline void setAckLimit(int mA) {
 	ackLimitmA = mA;
     }
-     
+    inline void setMinAckPulseDuration(unsigned int i) {
+	minAckPulseDuration = i;
+    }
+    inline void setMaxAckPulseDuration(unsigned int i) {
+	maxAckPulseDuration = i;
+    }
+
   private:
-    static VirtualTimer * interruptTimer;      
+    
+// For each state of the wave  nextState=stateTransform[currentState] 
+   static const WAVE_STATE stateTransform[6];
+
+// For each state of the wave, signal pin is HIGH or LOW   
+   static const bool signalTransform[6];
+  
     static void interruptHandler();
-    bool interrupt1();
     void interrupt2();
     void checkAck();
-    void setSignal(bool high);
     
     bool isMainTrack;
     MotorDriver*  motorDriver;
+    RMTPin* rmtPin;
     // Transmission controller
-    byte transmitPacket[MAX_PACKET_SIZE];  // packet being transmitted
+    byte transmitPacket[MAX_PACKET_SIZE+1]; // +1 for checksum
     byte transmitLength;
     byte transmitRepeats;      // remaining repeats of transmission
     byte remainingPreambles;
     byte requiredPreambles;
-    bool currentBit;           // bit to be transmitted
     byte bits_sent;           // 0-8 (yes 9 bits) sent for current byte
     byte bytes_sent;          // number of bytes sent from transmitPacket
-    byte state;               // wave generator state machine
-
-    byte pendingPacket[MAX_PACKET_SIZE];
+    WAVE_STATE state;         // wave generator state machine
+    byte pendingPacket[MAX_PACKET_SIZE+1]; // +1 for checksum
     byte pendingLength;
     byte pendingRepeats;
-    int lastCurrent;
-
+    int  lastCurrent;
+    static int progTripValue;
+    int maxmA;
+    int tripmA;
     
     // current sampling
     POWERMODE powerMode;
@@ -128,6 +163,12 @@ class DCCWaveform {
     
     unsigned int ackPulseDuration;  // micros
     unsigned long ackPulseStart; // micros
-           
+
+    unsigned int minAckPulseDuration = 4000; // micros
+    unsigned int maxAckPulseDuration = 8500; // micros
+
+    volatile static uint8_t numAckGaps;
+    volatile static uint8_t numAckSamples;
+    static uint8_t trailingEdgeCounter;
 };
 #endif

DIAG.h

@@ -18,6 +18,7 @@
  */
 #ifndef DIAG_h
 #define DIAG_h
+
 #include "StringFormatter.h"
 #define DIAG  StringFormatter::diag
 #define LCD   StringFormatter::lcd

DisplayInterface.cpp

@@ -0,0 +1,22 @@
+/*
+ *  © 2021, Chris Harlow, Neil McKechnie. All rights reserved.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "DisplayInterface.h"
+
+DisplayInterface *DisplayInterface::lcdDisplay = 0;

DisplayInterface.h

@@ -0,0 +1,35 @@
+/*
+ *  © 2021, Chris Harlow, Neil McKechnie. All rights reserved.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#ifndef DisplayInterface_h
+#define DisplayInterface_h
+
+#include <Arduino.h>
+
+// Definition of base class for displays.  The base class does nothing.
+class DisplayInterface : public Print {
+public:
+  virtual DisplayInterface* loop2(bool force) { (void)force; return NULL; };
+  virtual void setRow(byte line) { (void)line; };
+  virtual void clear() {};
+  virtual size_t write(uint8_t c) { (void)c; return 0; };
+
+  static DisplayInterface *lcdDisplay;
+};
+
+#endif

EEStore.cpp

@@ -19,88 +19,87 @@
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
 #include "EEStore.h"
-#include "Turnouts.h"
-#include "Sensors.h"
-#include "Outputs.h"
+
 #include "DIAG.h"
+#include "Outputs.h"
+#include "Sensors.h"
+#include "Turnouts.h"
 
 #if defined(ARDUINO_ARCH_SAMD)
 ExternalEEPROM EEPROM;
 #endif
 
-void EEStore::init(){
+void EEStore::init() {
 #if defined(ARDUINO_ARCH_SAMD)
-    EEPROM.begin(0x50);     // Address for Microchip 24-series EEPROM with all three A pins grounded (0b1010000 = 0x50)
+  EEPROM.begin(0x50);  // Address for Microchip 24-series EEPROM with all three
+                       // A pins grounded (0b1010000 = 0x50)
 #endif
 
-    eeStore=(EEStore *)calloc(1,sizeof(EEStore));
-    
-    EEPROM.get(0,eeStore->data);                                       // get eeStore data
+  eeStore = (EEStore *)calloc(1, sizeof(EEStore));
 
-    if(strncmp(eeStore->data.id,EESTORE_ID,sizeof(EESTORE_ID))!=0){    // check to see that eeStore contains valid DCC++ ID
-        sprintf(eeStore->data.id,EESTORE_ID);                           // if not, create blank eeStore structure (no turnouts, no sensors) and save it back to EEPROM
-        eeStore->data.nTurnouts=0;
-        eeStore->data.nSensors=0;
-        eeStore->data.nOutputs=0;
-        EEPROM.put(0,eeStore->data);
-    }
+  EEPROM.get(0, eeStore->data);  // get eeStore data
 
-    reset();            // set memory pointer to first free EEPROM space
-    Turnout::load();    // load turnout definitions
-    Sensor::load();     // load sensor definitions
-    Output::load();     // load output definitions
+  // check to see that eeStore contains valid DCC++ ID
+  if (strncmp(eeStore->data.id, EESTORE_ID, sizeof(EESTORE_ID)) != 0) {  
+    // if not, create blank eeStore structure (no
+    // turnouts, no sensors) and save it back to EEPROM  
+    strncpy(eeStore->data.id, EESTORE_ID, sizeof(EESTORE_ID));  
+    eeStore->data.nTurnouts = 0;
+    eeStore->data.nSensors = 0;
+    eeStore->data.nOutputs = 0;
+    EEPROM.put(0, eeStore->data);
+  }
 
+  reset();          // set memory pointer to first free EEPROM space
+  Turnout::load();  // load turnout definitions
+  Sensor::load();   // load sensor definitions
+  Output::load();   // load output definitions
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void EEStore::clear(){
-
-    sprintf(eeStore->data.id,EESTORE_ID);                           // create blank eeStore structure (no turnouts, no sensors) and save it back to EEPROM
-    eeStore->data.nTurnouts=0;
-    eeStore->data.nSensors=0;
-    eeStore->data.nOutputs=0;
-    EEPROM.put(0,eeStore->data);
-
+void EEStore::clear() {
+  sprintf(eeStore->data.id,
+          EESTORE_ID);  // create blank eeStore structure (no turnouts, no
+                        // sensors) and save it back to EEPROM
+  eeStore->data.nTurnouts = 0;
+  eeStore->data.nSensors = 0;
+  eeStore->data.nOutputs = 0;
+  EEPROM.put(0, eeStore->data);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void EEStore::store(){
-    reset();
-    Turnout::store();
-    Sensor::store();
-    Output::store();
-    EEPROM.put(0,eeStore->data);
+void EEStore::store() {
+  reset();
+  Turnout::store();
+  Sensor::store();
+  Output::store();
+  EEPROM.put(0, eeStore->data);
+  DIAG(F("EEPROM used: %d/%d bytes"), EEStore::pointer(), EEPROM.length());
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void EEStore::advance(int n){
-    eeAddress+=n;
-}
+void EEStore::advance(int n) { eeAddress += n; }
 
 ///////////////////////////////////////////////////////////////////////////////
 
-void EEStore::reset(){
-    eeAddress=sizeof(EEStore);
-}
+void EEStore::reset() { eeAddress = sizeof(EEStore); }
 ///////////////////////////////////////////////////////////////////////////////
 
-int EEStore::pointer(){
-    return(eeAddress);
-}
+int EEStore::pointer() { return (eeAddress); }
 ///////////////////////////////////////////////////////////////////////////////
 
 void EEStore::dump(int num) {
-    byte b;
-    DIAG(F("\nAddr  0x  char\n"));
-    for (int n=0 ; n<num; n++) {
-	EEPROM.get(n, b);
-	DIAG(F("%d     %x    %c\n"),n,b,isprint(b) ? b : ' ');
-    }
+  byte b;
+  DIAG(F("Addr  0x  char"));
+  for (int n = 0; n < num; n++) {
+    EEPROM.get(n, b);
+    DIAG(F("%d     %x    %c"), n, b, isprint(b) ? b : ' ');
+  }
 }
 ///////////////////////////////////////////////////////////////////////////////
 
-EEStore *EEStore::eeStore=NULL;
-int EEStore::eeAddress=0;
+EEStore *EEStore::eeStore = NULL;
+int EEStore::eeAddress = 0;

EEStore.h

@@ -1,3 +1,22 @@
+/*
+ *  (c) 2020 Chris Harlow. All rights reserved.
+ *  (c) 2020 Harald Barth. All rights reserved.
+ *  
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
 #ifndef EEStore_h
 #define EEStore_h
 
@@ -10,13 +29,13 @@ extern ExternalEEPROM EEPROM;
 #include <EEPROM.h>
 #endif
 
-#define EESTORE_ID "DCC++"
+#define EESTORE_ID "DCC++1"
 
 struct EEStoreData{
   char id[sizeof(EESTORE_ID)];
-  int nTurnouts;
-  int nSensors;  
-  int nOutputs;
+  uint16_t nTurnouts;
+  uint16_t nSensors;
+  uint16_t nOutputs;
 };
 
 struct EEStore{

EthernetInterface.cpp

@@ -17,10 +17,12 @@
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  * 
  */
-
+#include "defines.h" 
+#if ETHERNET_ON == true
 #include "EthernetInterface.h"
 #include "DIAG.h"
 #include "CommandDistributor.h"
+#include "DCCTimer.h"
 
 EthernetInterface * EthernetInterface::singleton=NULL;
 /**
@@ -42,23 +44,36 @@ void EthernetInterface::setup()
  */
 EthernetInterface::EthernetInterface()
 {
-    byte mac[]=MAC_ADDRESS;
-    
-    DIAG(F("\n+++++ Ethernet Setup "));
-        connected=false;
+    byte mac[6];
+    DCCTimer::getSimulatedMacAddress(mac);
+    connected=false;
    
+    #ifdef IP_ADDRESS
+    Ethernet.begin(mac, IP_ADDRESS);
+    #else
     if (Ethernet.begin(mac) == 0)
     {
-        DIAG(F("begin FAILED\n"));
+        DIAG(F("Ethernet.begin FAILED"));
         return;
     } 
+    #endif
     DIAG(F("begin OK."));
      if (Ethernet.hardwareStatus() == EthernetNoHardware) {
-      DIAG(F("shield not found\n"));
+      DIAG(F("Ethernet shield not found"));
       return;
     }
+  
+    unsigned long startmilli = millis();
+    while ((millis() - startmilli) < 5500) // Loop to give time to check for cable connection
+    {
+        if (Ethernet.linkStatus() == LinkON)
+            break;
+        DIAG(F("Ethernet waiting for link (1sec) "));
+        delay(1000);
+    }
+
     if (Ethernet.linkStatus() == LinkOFF) {
-      DIAG(F("cable not connected\n"));
+      DIAG(F("Ethernet cable not connected"));
       return;
     }
     
@@ -66,11 +81,11 @@ EthernetInterface::EthernetInterface()
     
     IPAddress ip = Ethernet.localIP(); // reassign the obtained ip address
 
-    server = new EthernetServer(LISTEN_PORT); // Ethernet Server listening on default port LISTEN_PORT
+    server = new EthernetServer(IP_PORT); // Ethernet Server listening on default port IP_PORT
     server->begin();
   
     LCD(4,F("IP: %d.%d.%d.%d"), ip[0], ip[1], ip[2], ip[3]);
-    LCD(5,F("Port:%d"), LISTEN_PORT);
+    LCD(5,F("Port:%d"), IP_PORT);
 
     outboundRing=new RingStream(OUTBOUND_RING_SIZE);     
 }
@@ -87,13 +102,13 @@ void EthernetInterface::loop()
     {
     case 1:
         //renewed fail
-        DIAG(F("\nEthernet Error: renewed fail\n"));
+        DIAG(F("Ethernet Error: renewed fail"));
         singleton=NULL;
         return;
 
     case 3:
         //rebind fail
-        DIAG(F("Ethernet Error: rebind fail\n"));
+        DIAG(F("Ethernet Error: rebind fail"));
         singleton=NULL;
         return;
 
@@ -114,7 +129,7 @@ void EthernetInterface::loop()
     // check for new client
     if (client)
     {
-        if (Diag::ETHERNET) DIAG(F("\nEthernet: New client "));
+        if (Diag::ETHERNET) DIAG(F("Ethernet: New client "));
         byte socket;
         for (socket = 0; socket < MAX_SOCK_NUM; socket++)
         {
@@ -122,12 +137,12 @@ void EthernetInterface::loop()
             {
                 // On accept() the EthernetServer doesn't track the client anymore
                 // so we store it in our client array
-                if (Diag::ETHERNET) DIAG(F("%d\n"),socket);
+                if (Diag::ETHERNET) DIAG(F("Socket %d"),socket);
                 clients[socket] = client;
                 break;
             }
         }
-        if (socket==MAX_SOCK_NUM) DIAG(F("new Ethernet OVERFLOW\n")); 
+        if (socket==MAX_SOCK_NUM) DIAG(F("new Ethernet OVERFLOW")); 
     }
 
     // check for incoming data from all possible clients
@@ -137,11 +152,11 @@ void EthernetInterface::loop()
         
         int available=clients[socket].available();
         if (available > 0) {
-            if (Diag::ETHERNET)  DIAG(F("\nEthernet: available socket=%d,avail=%d,count="), socket, available);
+            if (Diag::ETHERNET)  DIAG(F("Ethernet: available socket=%d,avail=%d"), socket, available);
             // read bytes from a client
             int count = clients[socket].read(buffer, MAX_ETH_BUFFER);
             buffer[count] = '\0'; // terminate the string properly
-            if (Diag::ETHERNET) DIAG(F("%d:%e\n"), socket,buffer);
+            if (Diag::ETHERNET) DIAG(F(",count=%d:%e"), socket,buffer);
             // execute with data going directly back
             outboundRing->mark(socket); 
             CommandDistributor::parse(socket,buffer,outboundRing);
@@ -155,7 +170,7 @@ void EthernetInterface::loop()
    for (int socket = 0; socket<MAX_SOCK_NUM; socket++) {
      if (clients[socket] && !clients[socket].connected()) {
       clients[socket].stop();
-      if (Diag::ETHERNET)  DIAG(F("\nEthernet: disconnect %d \n"), socket);             
+      if (Diag::ETHERNET)  DIAG(F("Ethernet: disconnect %d "), socket);             
      }
     }
     
@@ -163,11 +178,9 @@ void EthernetInterface::loop()
     int socketOut=outboundRing->read();
     if (socketOut>=0) {
       int count=outboundRing->count();
-      if (Diag::ETHERNET) DIAG(F("Ethernet reply socket=%d, count=:%d\n"), socketOut,count);
+      if (Diag::ETHERNET) DIAG(F("Ethernet reply socket=%d, count=:%d"), socketOut,count);
       for(;count>0;count--)  clients[socketOut].write(outboundRing->read());
       clients[socketOut].flush(); //maybe 
-      }
-      
     }
-
- 
+}
+#endif

EthernetInterface.h

@@ -23,32 +23,23 @@
 #ifndef EthernetInterface_h
 #define EthernetInterface_h
 
+#include "defines.h"
 #include "DCCEXParser.h"
-#include "MemStream.h"
 #include <Arduino.h>
 #include <avr/pgmspace.h>
-#include <Ethernet.h>
+#if defined (ARDUINO_TEENSY41)
+ #include <NativeEthernet.h>         //TEENSY Ethernet Treiber
+ #include <NativeEthernetUdp.h>   
+#else
+ #include "Ethernet.h"
+#endif
 #include "RingStream.h"
 
-/* some generated mac addresses as EthernetShields don't have one by default in HW.
- * Sometimes they come on a sticker on the EthernetShield then use this address otherwise
- * just choose one from below or generate one yourself. Only condition is that there is no 
- * other device on your network with the same Mac address.
- * 
- * 52:b8:8a:8e:ce:21
- * e3:e9:73:e1:db:0d
- * 54:2b:13:52:ac:0c
- * c2:d8:d4:7d:7c:cb
- * 86:cf:fa:9f:07:79
- */
-
 /**
  * @brief Network Configuration
  * 
  */
-#define MAC_ADDRESS { 0x52, 0xB8, 0x8A, 0x8E, 0xCE, 0x21 }      // MAC address of your networking card found on the sticker on your card or take one from above
-                                                                // this one is not used elsewhere and corresponds to your network layout
-#define LISTEN_PORT 2560                                        // default listen port for the server 
+
 #define MAX_ETH_BUFFER 512
 #define OUTBOUND_RING_SIZE 2048
 

FSH.h

@@ -0,0 +1,53 @@
+/*
+ *  (c) 2021 Fred Decker.  All rights reserved.
+ *  
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#ifndef FSH_h
+#define FSH_h
+
+/* This is an architecture support file to manage the differences 
+ *  between the nano/uno.mega and the later nanoEvery, unoWifiRev2 etc
+ *  
+ *  IMPORTANT:
+ *  To maintain portability the main code should NOT contain ANY references 
+ *  to the following: 
+ *  
+ *  __FlashStringHelper     Use FSH instead.
+ *  PROGMEM                 use FLASH instead
+ *  pgm_read_byte_near      use GETFLASH instead.
+ *  pgm_read_word_near      use GETFLASHW instead.
+ *  
+ */
+#include <Arduino.h>
+#if defined(ARDUINO_ARCH_MEGAAVR)
+#ifdef F
+  #undef F
+#endif
+#define F(str) (str)
+typedef char FSH; 
+#define GETFLASH(addr) (*(const unsigned char *)(addr))
+#define GETFLASHW(addr) (*(const unsigned short *)(addr))
+#define FLASH
+#define strlen_P strlen
+#define strcpy_P strcpy
+#else 
+typedef __FlashStringHelper FSH;
+#define GETFLASH(addr) pgm_read_byte_near(addr)
+#define GETFLASHW(addr) pgm_read_word_near(addr)
+#define FLASH PROGMEM
+#endif
+#endif

GITHUB_SHA.h

@@ -1 +1 @@
-#define GITHUB_SHA "9db6d36"
+#define GITHUB_SHA "ESP32-2021120-11:30"

I2CManager.cpp

@@ -0,0 +1,241 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <stdarg.h>
+#include "I2CManager.h"
+#include "DIAG.h"
+
+// Include target-specific portions of I2CManager class
+#if defined(I2C_USE_WIRE) 
+#include "I2CManager_Wire.h"
+#elif defined(ARDUINO_ARCH_AVR)
+#include "I2CManager_NonBlocking.h"
+#include "I2CManager_AVR.h"       // Uno/Nano/Mega2560
+#elif defined(ARDUINO_ARCH_MEGAAVR) 
+#include "I2CManager_NonBlocking.h"
+#include "I2CManager_Mega4809.h"  // NanoEvery/UnoWifi
+#else
+#define I2C_USE_WIRE
+#include "I2CManager_Wire.h"      // Other platforms
+#endif
+
+
+// If not already initialised, initialise I2C
+void I2CManagerClass::begin(void) {
+  //setTimeout(25000); // 25 millisecond timeout
+  if (!_beginCompleted) {
+    _beginCompleted = true;
+    _initialise();
+
+    // Probe and list devices.
+    bool found = false;
+    for (byte addr=1; addr<127; addr++) {
+      if (exists(addr)) {
+        found = true; 
+        DIAG(F("I2C Device found at x%x"), addr);
+      }
+    }
+    if (!found) DIAG(F("No I2C Devices found"));
+  }
+}
+
+// Set clock speed to the lowest requested one. If none requested,
+//  the Wire default is 100kHz.
+void I2CManagerClass::setClock(uint32_t speed) {
+  if (speed < _clockSpeed && !_clockSpeedFixed) {
+    _clockSpeed = speed;
+  }
+  _setClock(_clockSpeed);
+}
+
+// Force clock speed to that specified.  It can then only 
+// be overridden by calling Wire.setClock directly.
+void I2CManagerClass::forceClock(uint32_t speed) {
+  if (!_clockSpeedFixed) {
+    _clockSpeed = speed;
+    _clockSpeedFixed = true;
+    _setClock(_clockSpeed);
+  }
+}
+
+// Check if specified I2C address is responding (blocking operation)
+// Returns I2C_STATUS_OK (0) if OK, or error code.
+uint8_t I2CManagerClass::checkAddress(uint8_t address) {
+  return write(address, NULL, 0);
+}
+
+
+/***************************************************************************
+ *  Write a transmission to I2C using a list of data (blocking operation)
+ ***************************************************************************/
+uint8_t I2CManagerClass::write(uint8_t address, uint8_t nBytes, ...) {
+  uint8_t buffer[nBytes];
+  va_list args;
+  va_start(args, nBytes);
+  for (uint8_t i=0; i<nBytes; i++)
+    buffer[i] = va_arg(args, int);
+  va_end(args);
+  return write(address, buffer, nBytes);
+}
+
+/***************************************************************************
+ *  Initiate a write to an I2C device (blocking operation)
+ ***************************************************************************/
+uint8_t I2CManagerClass::write(uint8_t i2cAddress, const uint8_t writeBuffer[], uint8_t writeLen) {
+  I2CRB req;
+  uint8_t status = write(i2cAddress, writeBuffer, writeLen, &req);
+  return finishRB(&req, status);
+}
+
+/***************************************************************************
+ *  Initiate a write from PROGMEM (flash) to an I2C device (blocking operation)
+ ***************************************************************************/
+uint8_t I2CManagerClass::write_P(uint8_t i2cAddress, const uint8_t * data, uint8_t dataLen) {
+  I2CRB req;
+  uint8_t status = write_P(i2cAddress, data, dataLen, &req);
+  return finishRB(&req, status);
+}
+
+/***************************************************************************
+ *  Initiate a write (optional) followed by a read from the I2C device (blocking operation)
+ ***************************************************************************/
+uint8_t I2CManagerClass::read(uint8_t i2cAddress, uint8_t *readBuffer, uint8_t readLen, 
+    const uint8_t *writeBuffer, uint8_t writeLen)
+{
+  I2CRB req;
+  uint8_t status = read(i2cAddress, readBuffer, readLen, writeBuffer, writeLen, &req);
+  return finishRB(&req, status);
+}
+
+/***************************************************************************
+ *  Overload of read() to allow command to be specified as a series of bytes (blocking operation)
+ ***************************************************************************/
+uint8_t I2CManagerClass::read(uint8_t address, uint8_t readBuffer[], uint8_t readSize, 
+                                  uint8_t writeSize, ...) {
+  va_list args;
+  // Copy the series of bytes into an array.
+  va_start(args, writeSize);
+  uint8_t writeBuffer[writeSize];
+  for (uint8_t i=0; i<writeSize; i++)
+    writeBuffer[i] = va_arg(args, int);
+  va_end(args);
+  return read(address, readBuffer, readSize, writeBuffer, writeSize);
+}
+
+/***************************************************************************
+ * Finish off request block by posting status, etc. (blocking operation)
+ ***************************************************************************/
+uint8_t I2CManagerClass::finishRB(I2CRB *rb, uint8_t status) {
+  if ((status == I2C_STATUS_OK) && rb)
+    status = rb->wait();
+  return status;
+}
+
+/***************************************************************************
+ * Get a message corresponding to the error status
+ ***************************************************************************/
+const FSH *I2CManagerClass::getErrorMessage(uint8_t status) {
+  switch (status) {
+    case I2C_STATUS_OK: return F("OK");
+    case I2C_STATUS_TRUNCATED: return F("Transmission truncated");
+    case I2C_STATUS_NEGATIVE_ACKNOWLEDGE: return F("No response from device (address NAK)");
+    case I2C_STATUS_TRANSMIT_ERROR: return F("Transmit error (data NAK)");
+    case I2C_STATUS_OTHER_TWI_ERROR: return F("Other Wire/TWI error");
+    case I2C_STATUS_TIMEOUT: return F("Timeout");
+    case I2C_STATUS_ARBITRATION_LOST: return F("Arbitration lost");
+    case I2C_STATUS_BUS_ERROR: return F("I2C bus error");
+    case I2C_STATUS_UNEXPECTED_ERROR: return F("Unexpected error");
+    case I2C_STATUS_PENDING: return F("Request pending");
+    default: return F("Error code not recognised");
+  }
+}
+
+/***************************************************************************
+ *  Declare singleton class instance.
+ ***************************************************************************/
+I2CManagerClass I2CManager = I2CManagerClass();
+
+
+/////////////////////////////////////////////////////////////////////////////
+// Helper functions associated with I2C Request Block
+/////////////////////////////////////////////////////////////////////////////
+
+/***************************************************************************
+ *  Block waiting for request block to complete, and return completion status.
+ *  Since such a loop could potentially last for ever if the RB status doesn't
+ *  change, we set a high limit (1sec, 1000ms) on the wait time and, if it
+ *  hasn't changed by that time we assume it's not going to, and just return
+ *  a timeout status.  This means that CS will not lock up.
+ ***************************************************************************/
+uint8_t I2CRB::wait() {
+  unsigned long waitStart = millis();
+  do {
+    I2CManager.loop();
+    // Rather than looping indefinitely, let's set a very high timeout (1s).
+    if ((millis() - waitStart) > 1000UL) { 
+      DIAG(F("I2C TIMEOUT I2C:x%x I2CRB:x%x"), i2cAddress, this);
+      status = I2C_STATUS_TIMEOUT;
+      // Note that, although the timeout is posted, the request may yet complete.
+      // TODO: Ideally we would like to cancel the request.
+      return status;
+    }
+  } while (status==I2C_STATUS_PENDING);
+  return status;
+}
+
+/***************************************************************************
+ *  Check whether request is still in progress.
+ ***************************************************************************/
+bool I2CRB::isBusy() {
+  I2CManager.loop();
+  return (status==I2C_STATUS_PENDING);
+}
+
+/***************************************************************************
+ *  Helper functions to fill the I2CRequest structure with parameters.
+ ***************************************************************************/
+void I2CRB::setReadParams(uint8_t i2cAddress, uint8_t *readBuffer, uint8_t readLen) {
+  this->i2cAddress = i2cAddress;
+  this->writeLen = 0;
+  this->readBuffer = readBuffer;
+  this->readLen = readLen;
+  this->operation = OPERATION_READ;
+  this->status = I2C_STATUS_OK;
+}
+
+void I2CRB::setRequestParams(uint8_t i2cAddress, uint8_t *readBuffer, uint8_t readLen, 
+    const uint8_t *writeBuffer, uint8_t writeLen) {
+  this->i2cAddress = i2cAddress;
+  this->writeBuffer = writeBuffer;
+  this->writeLen = writeLen;
+  this->readBuffer = readBuffer;
+  this->readLen = readLen;
+  this->operation = OPERATION_REQUEST;
+  this->status = I2C_STATUS_OK;
+}
+
+void I2CRB::setWriteParams(uint8_t i2cAddress, const uint8_t *writeBuffer, uint8_t writeLen) {
+  this->i2cAddress = i2cAddress;
+  this->writeBuffer = writeBuffer;
+  this->writeLen = writeLen;
+  this->readLen = 0;
+  this->operation = OPERATION_SEND;
+  this->status = I2C_STATUS_OK;
+}
+

I2CManager.h

@@ -0,0 +1,288 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef I2CMANAGER_H
+#define I2CMANAGER_H
+
+#include <inttypes.h>
+#include "FSH.h"
+
+/* 
+ * Manager for I2C communications.  For portability, it allows use 
+ * of the Wire class, but also has a native implementation for AVR
+ * which supports non-blocking queued I/O requests.
+ * 
+ * Helps to avoid calling Wire.begin() multiple times (which is not)
+ * entirely benign as it reinitialises).
+ * 
+ * Also helps to avoid the Wire clock from being set, by another device
+ * driver, to a speed which is higher than a device supports.
+ * 
+ * Thirdly, it provides a convenient way to check whether there is a 
+ * device on a particular I2C address.
+ * 
+ * Non-blocking requests are issued by creating an I2C Request Block
+ * (I2CRB) which is then added to the I2C manager's queue.  The 
+ * application refers to this block to check for completion of the
+ * operation, and for reading completion status.
+ * 
+ * Examples:
+ *  I2CRB rb;
+ *  uint8_t status = I2CManager.write(address, buffer, sizeof(buffer), &rb);
+ *  ...
+ *  if (!rb.isBusy()) {
+ *    status = rb.status;
+ *    // Repeat write
+ *    I2CManager.queueRequest(&rb);
+ *    ...
+ *    status = rb.wait(); // Wait for completion and read status
+ *  }
+ *  ...
+ *  I2CRB rb2;
+ *  outbuffer[0] = 12;  // Register number in I2C device to be read
+ *  rb2.setRequestParams(address, inBuffer, 1, outBuffer, 1);
+ *  status = I2CManager.queueRequest(&rb2);
+ *  if (status == I2C_STATUS_OK) { 
+ *    status = rb2.wait();
+ *    if (status == I2C_STATUS_OK) {
+ *      registerValue = inBuffer[0];
+ *    }
+ *  }
+ *  ...
+ *  
+ * Synchronous (blocking) calls are also possible, e.g. 
+ *  status = I2CManager.write(address, buffer, sizeof(buffer));
+ * 
+ * When using non-blocking requests, neither the I2CRB nor the input or output
+ * buffers should be modified until the I2CRB is complete (not busy).
+ * 
+ * Timeout monitoring is possible, but requires that the following call is made
+ * reasonably frequently in the program's loop() function:
+ *  I2CManager.loop();
+ * 
+ */
+
+/* 
+ * Future enhancement possibility:
+ *
+ *  I2C Multiplexer (e.g. TCA9547, TCA9548)
+ * 
+ *  A multiplexer offers a way of extending the address range of I2C devices.  For example, GPIO extenders use address range 0x20-0x27
+ *  to are limited to 8 on a bus.  By adding a multiplexer, the limit becomes 8 for each of the multiplexer's 8 sub-buses, i.e. 64.
+ *  And a single I2C bus can have up to 8 multiplexers, giving up to 64 sub-buses and, in theory, up to 512 I/O extenders; that's 
+ *  as many as 8192 input/output pins!
+ *  Secondly, the capacitance of the bus is an electrical limiting factor of the length of the bus, speed and number of devices.
+ *  The multiplexer isolates each sub-bus from the others, and so reduces the capacitance of the bus.  For example, with one 
+ *  multiplexer and 64 GPIO extenders, only 9 devices are connected to the bus at any time (multiplexer plus 8 extenders). 
+ *  Thirdly, the multiplexer offers the ability to use mixed-speed devices more effectively, by allowing high-speed devices to be
+ *  put on a different bus to low-speed devices, enabling the software to switch the I2C speed on-the-fly between I2C transactions.
+ * 
+ *  Changes required:  Increase the size of the I2CAddress field in the IODevice class from uint8_t to uint16_t.
+ *  The most significant byte would contain a '1' bit flag, the multiplexer number (0-7) and bus number (0-7).  Then, when performing
+ *  an I2C operation, the I2CManager would check this byte and, if zero, do what it currently does.  If the byte is non-zero, then
+ *  that means the device is connected via a multiplexer so the I2C transaction should be preceded by a select command issued to the
+ *  relevant multiplexer.
+ * 
+ *  Non-interrupting I2C:
+ * 
+ *  I2C may be operated without interrupts (undefine I2C_USE_INTERRUPTS).  Instead, the I2C state
+ *  machine handler, currently invoked from the interrupt service routine, is invoked from the loop() function.
+ *  The speed at which I2C operations can be performed then becomes highly dependent on the frequency that 
+ *  the loop() function is called, and may be adequate under some circumstances.  
+ *  The advantage of NOT using interrupts is that the impact of I2C upon the DCC waveform (when accurate timing mode isn't in use)
+ *  becomes almost zero.
+ * 
+ */
+
+// Uncomment following line to enable Wire library instead of native I2C drivers
+//#define I2C_USE_WIRE
+
+// Uncomment following line to disable the use of interrupts by the native I2C drivers.
+//#define I2C_NO_INTERRUPTS
+
+// Default to use interrupts within the native I2C drivers.
+#ifndef I2C_NO_INTERRUPTS
+#define I2C_USE_INTERRUPTS
+#endif
+
+// Status codes for I2CRB structures.
+enum : uint8_t {
+  // Codes used by Wire and by native drivers
+  I2C_STATUS_OK=0,
+  I2C_STATUS_TRUNCATED=1,
+  I2C_STATUS_NEGATIVE_ACKNOWLEDGE=2,
+  I2C_STATUS_TRANSMIT_ERROR=3,
+  I2C_STATUS_TIMEOUT=5,
+  // Code used by Wire only
+  I2C_STATUS_OTHER_TWI_ERROR=4, // catch-all error
+  // Codes used by native drivers only
+  I2C_STATUS_ARBITRATION_LOST=6,
+  I2C_STATUS_BUS_ERROR=7,
+  I2C_STATUS_UNEXPECTED_ERROR=8,
+  I2C_STATUS_PENDING=253,
+};
+
+// Status codes for the state machine (not returned to caller).
+enum : uint8_t {
+  I2C_STATE_ACTIVE=253,
+  I2C_STATE_FREE=254,
+  I2C_STATE_CLOSING=255,
+};
+
+typedef enum : uint8_t
+{
+  OPERATION_READ = 1,
+  OPERATION_REQUEST = 2,
+  OPERATION_SEND = 3,
+  OPERATION_SEND_P = 4,
+} OperationEnum;
+
+
+// Default I2C frequency
+#ifndef I2C_FREQ
+#define I2C_FREQ    400000L
+#endif
+
+// Class defining a request context for an I2C operation.
+class I2CRB {
+public:
+  volatile uint8_t status; // Completion status, or pending flag (updated from IRC)
+  volatile uint8_t nBytes; // Number of bytes read (updated from IRC)
+
+  inline I2CRB() { status = I2C_STATUS_OK; };
+  uint8_t wait();
+  bool isBusy();
+
+  void setReadParams(uint8_t i2cAddress, uint8_t *readBuffer, uint8_t readLen);
+  void setRequestParams(uint8_t i2cAddress, uint8_t *readBuffer, uint8_t readLen, const uint8_t *writeBuffer, uint8_t writeLen);
+  void setWriteParams(uint8_t i2cAddress, const uint8_t *writeBuffer, uint8_t writeLen);
+
+  uint8_t writeLen;
+  uint8_t readLen;
+  uint8_t operation;
+  uint8_t i2cAddress;
+  uint8_t *readBuffer;
+  const uint8_t *writeBuffer;
+#if !defined(I2C_USE_WIRE)
+  I2CRB *nextRequest;
+#endif
+};
+
+// I2C Manager
+class I2CManagerClass {
+public:
+
+  // If not already initialised, initialise I2C (wire).
+  void begin(void);
+  // Set clock speed to the lowest requested one.
+  void setClock(uint32_t speed);
+  // Force clock speed 
+  void forceClock(uint32_t speed);
+  // Check if specified I2C address is responding.
+  uint8_t checkAddress(uint8_t address);
+  inline bool exists(uint8_t address) {
+    return checkAddress(address)==I2C_STATUS_OK;
+  }
+  // Write a complete transmission to I2C from an array in RAM
+  uint8_t write(uint8_t address, const uint8_t buffer[], uint8_t size);
+  uint8_t write(uint8_t address, const uint8_t buffer[], uint8_t size, I2CRB *rb);
+  // Write a complete transmission to I2C from an array in Flash
+  uint8_t write_P(uint8_t address, const uint8_t buffer[], uint8_t size);
+  uint8_t write_P(uint8_t address, const uint8_t buffer[], uint8_t size, I2CRB *rb);
+  // Write a transmission to I2C from a list of bytes.
+  uint8_t write(uint8_t address, uint8_t nBytes, ...);
+  // Write a command from an array in RAM and read response
+  uint8_t read(uint8_t address, uint8_t readBuffer[], uint8_t readSize, 
+    const uint8_t writeBuffer[]=NULL, uint8_t writeSize=0);
+  uint8_t read(uint8_t address, uint8_t readBuffer[], uint8_t readSize, 
+    const uint8_t writeBuffer[], uint8_t writeSize, I2CRB *rb);
+  // Write a command from an arbitrary list of bytes and read response
+  uint8_t read(uint8_t address, uint8_t readBuffer[], uint8_t readSize, 
+    uint8_t writeSize, ...);
+  void queueRequest(I2CRB *req);
+
+  // Function to abort long-running operations.
+  void checkForTimeout();
+
+  // Loop method
+  void loop();
+
+  // Expand error codes into text.  Note that they are in flash so 
+  // need to be printed using FSH.
+  static const FSH *getErrorMessage(uint8_t status);
+
+private:
+  bool _beginCompleted = false;
+  bool _clockSpeedFixed = false;
+  uint32_t _clockSpeed = 400000L;  // 400kHz max on Arduino.
+
+  // Finish off request block by waiting for completion and posting status.
+  uint8_t finishRB(I2CRB *rb, uint8_t status);
+
+  void _initialise();
+  void _setClock(unsigned long);
+
+#if !defined(I2C_USE_WIRE)
+    // I2CRB structs are queued on the following two links.
+    // If there are no requests, both are NULL.
+    // If there is only one request, then queueHead and queueTail both point to it.
+    // Otherwise, queueHead is the pointer to the first request in the queue and
+    // queueTail is the pointer to the last request in the queue.
+    // Within the queue, each request's nextRequest field points to the 
+    // next request, or NULL.
+    // Mark volatile as they are updated by IRC and read/written elsewhere.
+    static I2CRB * volatile queueHead;
+    static I2CRB * volatile queueTail;
+    static volatile uint8_t state;
+
+    static I2CRB * volatile currentRequest;
+    static volatile uint8_t txCount;
+    static volatile uint8_t rxCount;
+    static volatile uint8_t bytesToSend;
+    static volatile uint8_t bytesToReceive;
+    static volatile uint8_t operation;
+    static volatile unsigned long startTime;
+
+    static unsigned long timeout; // Transaction timeout in microseconds.  0=disabled.
+    
+    void startTransaction();
+    
+    // Low-level hardware manipulation functions.
+    static void I2C_init();
+    static void I2C_setClock(unsigned long i2cClockSpeed);
+    static void I2C_handleInterrupt();
+    static void I2C_sendStart();
+    static void I2C_sendStop();
+    static void I2C_close();
+    
+  public:
+    // setTimeout sets the timout value for I2C transactions.
+    // TODO: Get I2C timeout working before uncommenting the code below.
+    void setTimeout(unsigned long value) { (void)value; /* timeout = value; */ };
+
+    // handleInterrupt needs to be public to be called from the ISR function!
+    static void handleInterrupt();
+#endif
+
+
+};
+
+extern I2CManagerClass I2CManager;
+
+#endif

I2CManager_AVR.h

@@ -0,0 +1,209 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef I2CMANAGER_AVR_H
+#define I2CMANAGER_AVR_H
+
+#include <Arduino.h>
+#include "I2CManager.h"
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+
+/****************************************************************************
+  TWI State codes
+****************************************************************************/
+// General TWI Master staus codes                      
+#define TWI_START                  0x08  // START has been transmitted  
+#define TWI_REP_START              0x10  // Repeated START has been transmitted
+#define TWI_ARB_LOST               0x38  // Arbitration lost
+
+// TWI Master Transmitter staus codes                      
+#define TWI_MTX_ADR_ACK            0x18  // SLA+W has been tramsmitted and ACK received
+#define TWI_MTX_ADR_NACK           0x20  // SLA+W has been tramsmitted and NACK received 
+#define TWI_MTX_DATA_ACK           0x28  // Data byte has been tramsmitted and ACK received
+#define TWI_MTX_DATA_NACK          0x30  // Data byte has been tramsmitted and NACK received 
+
+// TWI Master Receiver staus codes  
+#define TWI_MRX_ADR_ACK            0x40  // SLA+R has been tramsmitted and ACK received
+#define TWI_MRX_ADR_NACK           0x48  // SLA+R has been tramsmitted and NACK received
+#define TWI_MRX_DATA_ACK           0x50  // Data byte has been received and ACK tramsmitted
+#define TWI_MRX_DATA_NACK          0x58  // Data byte has been received and NACK tramsmitted
+
+// TWI Miscellaneous status codes
+#define TWI_NO_STATE               0xF8  // No relevant state information available
+#define TWI_BUS_ERROR              0x00  // Bus error due to an illegal START or STOP condition
+
+#define TWI_TWBR  ((F_CPU / I2C_FREQ) - 16) / 2 // TWI Bit rate Register setting.
+
+#if defined(I2C_USE_INTERRUPTS)
+#define ENABLE_TWI_INTERRUPT (1<<TWIE)
+#else
+#define ENABLE_TWI_INTERRUPT 0
+#endif
+
+/***************************************************************************
+ *  Set I2C clock speed register.
+ ***************************************************************************/
+void I2CManagerClass::I2C_setClock(unsigned long i2cClockSpeed) {
+  unsigned long temp = ((F_CPU / i2cClockSpeed) - 16) / 2;
+  for (uint8_t preScaler = 0; preScaler<=3; preScaler++) {
+    if (temp <= 255) {
+      TWBR = temp;
+      TWSR = (TWSR & 0xfc) | preScaler;
+      return;
+    } else 
+      temp /= 4;
+  }
+  // Set slowest speed ~= 500 bits/sec
+  TWBR = 255;
+  TWSR |= 0x03;
+}
+
+/***************************************************************************
+ *  Initialise I2C registers.
+ ***************************************************************************/
+void I2CManagerClass::I2C_init()
+{
+  TWSR = 0;
+  TWBR = TWI_TWBR;                                  // Set bit rate register (Baudrate). Defined in header file.
+  TWDR = 0xFF;                                      // Default content = SDA released.
+  TWCR = (1<<TWINT);                                // Clear interrupt flag
+ 
+  pinMode(SDA, INPUT_PULLUP);
+  pinMode(SCL, INPUT_PULLUP);
+}
+
+/***************************************************************************
+ *  Initiate a start bit for transmission.
+ ***************************************************************************/
+void I2CManagerClass::I2C_sendStart() {
+  bytesToSend = currentRequest->writeLen;
+  bytesToReceive = currentRequest->readLen;
+  // We may have initiated a stop bit before this without waiting for it.
+  // Wait for stop bit to be sent before sending start.
+  while (TWCR & (1<<TWSTO)) {}
+  TWCR = (1<<TWEN)|ENABLE_TWI_INTERRUPT|(1<<TWINT)|(1<<TWEA)|(1<<TWSTA);  // Send Start
+}
+
+/***************************************************************************
+ *  Initiate a stop bit for transmission (does not interrupt)
+ ***************************************************************************/
+void I2CManagerClass::I2C_sendStop() {
+  TWDR = 0xff;  // Default condition = SDA released
+  TWCR = (1<<TWEN)|(1<<TWINT)|(1<<TWEA)|(1<<TWSTO);  // Send Stop
+}
+
+/***************************************************************************
+ *  Close I2C down
+ ***************************************************************************/
+void I2CManagerClass::I2C_close() {
+  // disable TWI
+  I2C_sendStop();
+  while (TWCR & (1<<TWSTO)) {}
+  TWCR = (1<<TWINT);                 // clear any interrupt and stop twi.
+}
+
+/***************************************************************************
+ *  Main state machine for I2C, called from interrupt handler or,
+ *  if I2C_USE_INTERRUPTS isn't defined, from the I2CManagerClass::loop() function
+ *  (and therefore, indirectly, from I2CRB::wait() and I2CRB::isBusy()).
+ ***************************************************************************/
+void I2CManagerClass::I2C_handleInterrupt() {
+  if (!(TWCR & (1<<TWINT))) return;  // Nothing to do.
+
+  uint8_t twsr = TWSR & 0xF8;
+
+  // Cases are ordered so that the most frequently used ones are tested first.
+  switch (twsr) {
+    case TWI_MTX_DATA_ACK:      // Data byte has been transmitted and ACK received
+    case TWI_MTX_ADR_ACK:       // SLA+W has been transmitted and ACK received
+      if (bytesToSend) {  // Send first.
+        if (operation == OPERATION_SEND_P)
+          TWDR = GETFLASH(currentRequest->writeBuffer + (txCount++));
+        else
+          TWDR = currentRequest->writeBuffer[txCount++];
+        bytesToSend--;
+        TWCR = (1<<TWEN)|ENABLE_TWI_INTERRUPT|(1<<TWINT)|(1<<TWEA);
+      } else if (bytesToReceive) {  // All sent, anything to receive?
+        while (TWCR & (1<<TWSTO)) {}    // Wait for stop to be sent
+        TWCR = (1<<TWEN)|ENABLE_TWI_INTERRUPT|(1<<TWINT)|(1<<TWEA)|(1<<TWSTA);  // Send Start
+      } else {  // Nothing left to send or receive
+        TWDR = 0xff;  // Default condition = SDA released
+        TWCR = (1<<TWEN)|(1<<TWINT)|(1<<TWEA)|(1<<TWSTO);  // Send Stop
+        state = I2C_STATUS_OK;
+      }
+      break;
+    case TWI_MRX_DATA_ACK:      // Data byte has been received and ACK transmitted
+      if (bytesToReceive > 0) {
+        currentRequest->readBuffer[rxCount++] = TWDR;
+        bytesToReceive--;
+      }
+      /* fallthrough */
+    case TWI_MRX_ADR_ACK:      // SLA+R has been sent and ACK received
+      if (bytesToReceive <= 1) {
+        TWCR = (1<<TWEN)|ENABLE_TWI_INTERRUPT|(1<<TWINT); // Send NACK after next reception
+      } else {
+        // send ack
+        TWCR = (1<<TWEN)|ENABLE_TWI_INTERRUPT|(1<<TWINT)|(1<<TWEA);
+      }
+      break;
+    case TWI_MRX_DATA_NACK:     // Data byte has been received and NACK transmitted
+      if (bytesToReceive > 0) {
+        currentRequest->readBuffer[rxCount++] = TWDR;
+        bytesToReceive--;
+      }
+      TWCR = (1<<TWEN)|(1<<TWINT)|(1<<TWEA)|(1<<TWSTO);  // Send Stop
+      state = I2C_STATUS_OK;
+      break;
+    case TWI_START:             // START has been transmitted  
+    case TWI_REP_START:         // Repeated START has been transmitted
+      // Set up address and R/W
+      if (operation == OPERATION_READ || (operation==OPERATION_REQUEST && !bytesToSend))
+        TWDR = (currentRequest->i2cAddress << 1) | 1; // SLA+R
+      else
+        TWDR = (currentRequest->i2cAddress << 1) | 0; // SLA+W
+      TWCR = (1<<TWEN)|ENABLE_TWI_INTERRUPT|(1<<TWINT)|(1<<TWEA);
+      break;
+    case TWI_MTX_ADR_NACK:      // SLA+W has been transmitted and NACK received
+    case TWI_MRX_ADR_NACK:      // SLA+R has been transmitted and NACK received
+    case TWI_MTX_DATA_NACK:     // Data byte has been transmitted and NACK received
+      TWDR = 0xff;  // Default condition = SDA released
+      TWCR = (1<<TWEN)|(1<<TWINT)|(1<<TWEA)|(1<<TWSTO);  // Send Stop
+      state = I2C_STATUS_NEGATIVE_ACKNOWLEDGE;
+      break;
+    case TWI_ARB_LOST:          // Arbitration lost
+      // Restart transaction from start.
+      I2C_sendStart();
+      break;
+    case TWI_BUS_ERROR:         // Bus error due to an illegal START or STOP condition
+    default:
+      TWDR = 0xff;  // Default condition = SDA released
+      TWCR = (1<<TWEN)|(1<<TWINT)|(1<<TWEA)|(1<<TWSTO);  // Send Stop
+      state = I2C_STATUS_TRANSMIT_ERROR;
+  }
+}
+
+#if defined(I2C_USE_INTERRUPTS)
+ISR(TWI_vect) {
+  I2CManagerClass::handleInterrupt();
+}
+#endif
+
+#endif /* I2CMANAGER_AVR_H */

I2CManager_Mega4809.h

@@ -0,0 +1,160 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef I2CMANAGER_MEGA4809_H
+#define I2CMANAGER_MEGA4809_H
+
+#include <Arduino.h>
+#include "I2CManager.h"
+
+/***************************************************************************
+ *  Set I2C clock speed register.
+ ***************************************************************************/
+void I2CManagerClass::I2C_setClock(unsigned long i2cClockSpeed) {
+  uint16_t t_rise;
+  if (i2cClockSpeed < 200000) {
+    i2cClockSpeed = 100000;
+    t_rise = 1000;
+  } else if (i2cClockSpeed < 800000) {
+    i2cClockSpeed = 400000;
+    t_rise = 300;
+  } else if (i2cClockSpeed < 1200000) {
+    i2cClockSpeed = 1000000;
+    t_rise = 120;
+  } else {
+    i2cClockSpeed = 100000;
+    t_rise = 1000;
+  }
+  uint32_t baud = (F_CPU_CORRECTED / i2cClockSpeed - F_CPU_CORRECTED / 1000 / 1000
+    * t_rise / 1000 - 10) / 2;
+  TWI0.MBAUD = (uint8_t)baud;
+}
+
+/***************************************************************************
+ *  Initialise I2C registers.
+ ***************************************************************************/
+void I2CManagerClass::I2C_init()
+{ 
+  pinMode(PIN_WIRE_SDA, INPUT_PULLUP);
+  pinMode(PIN_WIRE_SCL, INPUT_PULLUP);
+  PORTMUX.TWISPIROUTEA |= TWI_MUX;
+
+#if defined(I2C_USE_INTERRUPTS)
+  TWI0.MCTRLA = TWI_RIEN_bm | TWI_WIEN_bm | TWI_ENABLE_bm;
+#else
+  TWI0.MCTRLA = TWI_ENABLE_bm;
+#endif
+  I2C_setClock(I2C_FREQ);
+  TWI0.MSTATUS = TWI_BUSSTATE_IDLE_gc;
+}
+
+/***************************************************************************
+ *  Initiate a start bit for transmission, followed by address and R/W
+ ***************************************************************************/
+void I2CManagerClass::I2C_sendStart() {
+  bytesToSend = currentRequest->writeLen;
+  bytesToReceive = currentRequest->readLen;
+
+  // If anything to send, initiate write.  Otherwise initiate read.
+  if (operation == OPERATION_READ || (operation == OPERATION_REQUEST & !bytesToSend))
+    TWI0.MADDR = (currentRequest->i2cAddress << 1) | 1;
+  else
+    TWI0.MADDR = (currentRequest->i2cAddress << 1) | 0;
+}
+
+/***************************************************************************
+ *  Initiate a stop bit for transmission.
+ ***************************************************************************/
+void I2CManagerClass::I2C_sendStop() {
+  TWI0.MCTRLB = TWI_MCMD_STOP_gc;
+}
+
+/***************************************************************************
+ *  Close I2C down
+ ***************************************************************************/
+void I2CManagerClass::I2C_close() {
+  I2C_sendStop();
+}
+
+/***************************************************************************
+ *  Main state machine for I2C, called from interrupt handler.
+ ***************************************************************************/
+void I2CManagerClass::I2C_handleInterrupt() {
+  
+  uint8_t currentStatus = TWI0.MSTATUS;
+
+  if (currentStatus & TWI_ARBLOST_bm) {
+    // Arbitration lost, restart
+    TWI0.MSTATUS = currentStatus; // clear all flags
+    I2C_sendStart();   // Reinitiate request
+  } else if (currentStatus & TWI_BUSERR_bm) {
+    // Bus error
+    state = I2C_STATUS_BUS_ERROR;
+    TWI0.MSTATUS = currentStatus; // clear all flags
+  } else if (currentStatus & TWI_WIF_bm) {
+    // Master write completed
+    if (currentStatus & TWI_RXACK_bm) {
+      // Nacked, send stop.
+      TWI0.MCTRLB = TWI_MCMD_STOP_gc;
+      state = I2C_STATUS_NEGATIVE_ACKNOWLEDGE;
+    } else if (bytesToSend) {
+      // Acked, so send next byte
+      if (currentRequest->operation == OPERATION_SEND_P)
+        TWI0.MDATA = GETFLASH(currentRequest->writeBuffer + (txCount++));
+      else
+        TWI0.MDATA = currentRequest->writeBuffer[txCount++];
+      bytesToSend--;
+    } else if (bytesToReceive) {
+        // Last sent byte acked and no more to send.  Send repeated start, address and read bit.
+        TWI0.MADDR = (currentRequest->i2cAddress << 1) | 1;
+    } else {
+      // No more data to send/receive. Initiate a STOP condition.
+      TWI0.MCTRLB = TWI_MCMD_STOP_gc;
+      state = I2C_STATUS_OK;  // Done
+    }
+  } else if (currentStatus & TWI_RIF_bm) {
+    // Master read completed without errors
+    if (bytesToReceive) {
+      currentRequest->readBuffer[rxCount++] = TWI0.MDATA;  // Store received byte
+      bytesToReceive--;
+    } else { 
+      // Buffer full, issue nack/stop
+      TWI0.MCTRLB = TWI_ACKACT_bm | TWI_MCMD_STOP_gc;
+      state = I2C_STATUS_OK;
+    }
+    if (bytesToReceive) {
+      // More bytes to receive, issue ack and start another read
+      TWI0.MCTRLB = TWI_MCMD_RECVTRANS_gc;
+    } else {
+      // Transaction finished, issue NACK and STOP.
+      TWI0.MCTRLB = TWI_ACKACT_bm | TWI_MCMD_STOP_gc;
+      state = I2C_STATUS_OK;
+    }
+  }
+}
+
+
+/***************************************************************************
+ *  Interrupt handler.
+ ***************************************************************************/
+ISR(TWI0_TWIM_vect) {
+  I2CManagerClass::handleInterrupt();
+}
+
+#endif

I2CManager_NonBlocking.h

@@ -0,0 +1,224 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef I2CMANAGER_NONBLOCKING_H
+#define I2CMANAGER_NONBLOCKING_H
+
+#include <Arduino.h>
+#include "I2CManager.h"
+#if defined(I2C_USE_INTERRUPTS)
+#include <util/atomic.h>
+#else
+#define ATOMIC_BLOCK(x) 
+#define ATOMIC_RESTORESTATE
+#endif
+
+// This module is only compiled if I2C_USE_WIRE is not defined, so undefine it here
+// to get intellisense to work correctly.
+#if defined(I2C_USE_WIRE)
+#undef I2C_USE_WIRE
+#endif
+
+/***************************************************************************
+ * Initialise the I2CManagerAsync class.
+ ***************************************************************************/
+void I2CManagerClass::_initialise()
+{
+  queueHead = queueTail = NULL;
+  state = I2C_STATE_FREE;
+  I2C_init();
+}
+
+/***************************************************************************
+ *  Set I2C clock speed.  Normally 100000 (Standard) or 400000 (Fast)
+ *   on Arduino.  Mega4809 supports 1000000 (Fast+) too.
+ ***************************************************************************/
+void I2CManagerClass::_setClock(unsigned long i2cClockSpeed) {
+  I2C_setClock(i2cClockSpeed);
+}
+
+/***************************************************************************
+ * Helper function to start operations, if the I2C interface is free and
+ * there is a queued request to be processed.
+ ***************************************************************************/
+void I2CManagerClass::startTransaction() { 
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    if ((state == I2C_STATE_FREE) && (queueHead != NULL)) {
+      state = I2C_STATE_ACTIVE;
+      currentRequest = queueHead;
+      rxCount = txCount = 0;
+      // Copy key fields to static data for speed.
+      operation = currentRequest->operation;
+      // Start the I2C process going.
+      I2C_sendStart();
+      startTime = micros();
+    }
+  }
+}
+
+/***************************************************************************
+ *  Function to queue a request block and initiate operations.
+ ***************************************************************************/
+void I2CManagerClass::queueRequest(I2CRB *req) {
+  req->status = I2C_STATUS_PENDING;
+  req->nextRequest = NULL;
+
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    if (!queueTail) 
+      queueHead = queueTail = req;  // Only item on queue
+    else
+      queueTail = queueTail->nextRequest = req; // Add to end
+    startTransaction();
+  }
+
+}
+
+/***************************************************************************
+ *  Initiate a write to an I2C device (non-blocking operation)
+ ***************************************************************************/
+uint8_t I2CManagerClass::write(uint8_t i2cAddress, const uint8_t *writeBuffer, uint8_t writeLen, I2CRB *req) {
+  // Make sure previous request has completed.
+  req->wait();
+  req->setWriteParams(i2cAddress, writeBuffer, writeLen);
+  queueRequest(req);
+  return I2C_STATUS_OK;
+}
+
+/***************************************************************************
+ *  Initiate a write from PROGMEM (flash) to an I2C device (non-blocking operation)
+ ***************************************************************************/
+uint8_t I2CManagerClass::write_P(uint8_t i2cAddress, const uint8_t * writeBuffer, uint8_t writeLen, I2CRB *req) {
+  // Make sure previous request has completed.
+  req->wait();
+  req->setWriteParams(i2cAddress, writeBuffer, writeLen);
+  req->operation = OPERATION_SEND_P;
+  queueRequest(req);
+  return I2C_STATUS_OK;
+}
+
+/***************************************************************************
+ *  Initiate a read from the I2C device, optionally preceded by a write 
+ *   (non-blocking operation)
+ ***************************************************************************/
+uint8_t I2CManagerClass::read(uint8_t i2cAddress, uint8_t *readBuffer, uint8_t readLen, 
+    const uint8_t *writeBuffer, uint8_t writeLen, I2CRB *req)
+{
+  // Make sure previous request has completed.
+  req->wait();
+  req->setRequestParams(i2cAddress, readBuffer, readLen, writeBuffer, writeLen);
+  queueRequest(req);
+  return I2C_STATUS_OK;
+}
+
+/***************************************************************************
+ * checkForTimeout() function, called from isBusy() and wait() to cancel
+ * requests that are taking too long to complete.
+ * This function doesn't fully work as intended so is not currently called.
+ * Instead we check for an I2C hang-up and report an error from
+ * I2CRB::wait(), but we aren't able to recover from the hang-up.  Such faults
+ * may be caused by an I2C wire short for example.
+ ***************************************************************************/
+void I2CManagerClass::checkForTimeout() {
+  unsigned long currentMicros = micros();
+  ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+    I2CRB *t = queueHead;
+    if (state==I2C_STATE_ACTIVE && t!=0 && t==currentRequest && timeout > 0) {
+      // Check for timeout
+      if (currentMicros - startTime > timeout) { 
+        // Excessive time. Dequeue request
+        queueHead = t->nextRequest;
+        if (!queueHead) queueTail = NULL;
+        currentRequest = NULL;
+        // Post request as timed out.
+        t->status = I2C_STATUS_TIMEOUT;
+        // Reset TWI interface so it is able to continue
+        // Try close and init, not entirely satisfactory but sort of works...
+        I2C_close();  // Shutdown and restart twi interface
+        I2C_init();
+        state = I2C_STATE_FREE;
+        
+        // Initiate next queued request if any.
+        startTransaction();
+      }
+    }
+  }
+}
+
+/***************************************************************************
+ *  Loop function, for general background work
+ ***************************************************************************/
+void I2CManagerClass::loop() {
+#if !defined(I2C_USE_INTERRUPTS)
+  handleInterrupt();
+#endif
+  // Timeout is now reported in I2CRB::wait(), not here.
+  // I've left the code, commented out, as a reminder to look at this again
+  // in the future.
+  //checkForTimeout();
+}
+
+/***************************************************************************
+ * Interupt handler.  Call I2C state machine, and dequeue request
+ * if completed.
+ ***************************************************************************/
+void I2CManagerClass::handleInterrupt() {
+
+  // Update hardware state machine
+  I2C_handleInterrupt();
+
+  // Enable interrupts to minimise effect on other interrupt code
+  interrupts();
+
+  // Check if current request has completed.  If there's a current request
+  // and state isn't active then state contains the completion status of the request.
+  if (state != I2C_STATE_ACTIVE && currentRequest != NULL) {
+    // Remove completed request from head of queue
+    ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
+      I2CRB * t = queueHead;
+      if (t == queueHead) {
+        queueHead = t->nextRequest;
+        if (!queueHead) queueTail = queueHead;
+        t->nBytes = rxCount;
+        t->status = state;
+        
+        // I2C state machine is now free for next request
+        currentRequest = NULL;
+        state = I2C_STATE_FREE;
+
+        // Start next request (if any)
+        I2CManager.startTransaction();
+      }
+    }
+  }
+}
+
+// Fields in I2CManager class specific to Non-blocking implementation.
+I2CRB * volatile I2CManagerClass::queueHead = NULL;
+I2CRB * volatile I2CManagerClass::queueTail = NULL;
+I2CRB * volatile I2CManagerClass::currentRequest = NULL;
+volatile uint8_t I2CManagerClass::state = I2C_STATE_FREE;
+volatile uint8_t I2CManagerClass::txCount;
+volatile uint8_t I2CManagerClass::rxCount;
+volatile uint8_t I2CManagerClass::operation;
+volatile uint8_t I2CManagerClass::bytesToSend;
+volatile uint8_t I2CManagerClass::bytesToReceive;
+volatile unsigned long I2CManagerClass::startTime;
+unsigned long I2CManagerClass::timeout = 0;
+
+#endif

I2CManager_Wire.h

@@ -0,0 +1,128 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef I2CMANAGER_WIRE_H
+#define I2CMANAGER_WIRE_H
+
+#include <Arduino.h>
+#include <Wire.h>
+#include "I2CManager.h"
+
+// This module is only compiled if I2C_USE_WIRE is defined, so define it here
+// to get intellisense to work correctly.
+#if !defined(I2C_USE_WIRE)
+#define I2C_USE_WIRE
+#endif
+
+/***************************************************************************
+ *  Initialise I2C interface software
+ ***************************************************************************/
+void I2CManagerClass::_initialise() {
+  Wire.begin();
+}
+
+/***************************************************************************
+ *  Set I2C clock speed.  Normally 100000 (Standard) or 400000 (Fast)
+ *   on Arduino.  Mega4809 supports 1000000 (Fast+) too.
+ ***************************************************************************/
+void I2CManagerClass::_setClock(unsigned long i2cClockSpeed) {
+  Wire.setClock(i2cClockSpeed);
+}
+
+/***************************************************************************
+ *  Initiate a write to an I2C device (blocking operation on Wire)
+ ***************************************************************************/
+uint8_t I2CManagerClass::write(uint8_t address, const uint8_t buffer[], uint8_t size, I2CRB *rb) {
+  Wire.beginTransmission(address);
+  if (size > 0) Wire.write(buffer, size);
+  rb->status = Wire.endTransmission();
+  return I2C_STATUS_OK;
+}
+
+/***************************************************************************
+ *  Initiate a write from PROGMEM (flash) to an I2C device (blocking operation on Wire)
+ ***************************************************************************/
+uint8_t I2CManagerClass::write_P(uint8_t address, const uint8_t buffer[], uint8_t size, I2CRB *rb) {
+  uint8_t ramBuffer[size];
+  const uint8_t *p1 = buffer;
+  for (uint8_t i=0; i<size; i++)
+    ramBuffer[i] = GETFLASH(p1++);
+  return write(address, ramBuffer, size, rb);
+}
+
+/***************************************************************************
+ *  Initiate a write (optional) followed by a read from the I2C device (blocking operation on Wire)
+ *  If fewer than the number of requested bytes are received, status is I2C_STATUS_TRUNCATED.
+ ***************************************************************************/
+uint8_t I2CManagerClass::read(uint8_t address, uint8_t readBuffer[], uint8_t readSize,
+                              const uint8_t writeBuffer[], uint8_t writeSize, I2CRB *rb)
+{
+  uint8_t status = I2C_STATUS_OK;
+  uint8_t nBytes = 0;
+  if (writeSize > 0) {
+    Wire.beginTransmission(address);
+    Wire.write(writeBuffer, writeSize);
+    status = Wire.endTransmission(false); // Don't free bus yet
+  }
+  if (status == I2C_STATUS_OK) {
+    Wire.requestFrom(address, (size_t)readSize);
+    while (Wire.available() && nBytes < readSize) 
+      readBuffer[nBytes++] = Wire.read();
+    if (nBytes < readSize) status = I2C_STATUS_TRUNCATED;
+  }
+  rb->nBytes = nBytes;
+  rb->status = status;
+  return I2C_STATUS_OK;
+}
+
+/***************************************************************************
+ *  Function to queue a request block and initiate operations.
+ * 
+ * For the Wire version, this executes synchronously, but the status is
+ * returned in the I2CRB as for the asynchronous version.
+ ***************************************************************************/
+void I2CManagerClass::queueRequest(I2CRB *req) {
+  uint8_t status;
+  switch (req->operation) {
+    case OPERATION_READ:
+      status = read(req->i2cAddress, req->readBuffer, req->readLen, NULL, 0, req);
+      break;
+    case OPERATION_SEND:
+      status = write(req->i2cAddress, req->writeBuffer, req->writeLen, req);
+      break;
+    case OPERATION_SEND_P:
+      status = write_P(req->i2cAddress, req->writeBuffer, req->writeLen, req);
+      break;
+    case OPERATION_REQUEST:
+      status = read(req->i2cAddress, req->readBuffer, req->readLen, req->writeBuffer, req->writeLen, req);
+      break;
+  }
+  req->status = status;
+}
+
+/***************************************************************************
+ *  Loop function, for general background work
+ ***************************************************************************/
+void I2CManagerClass::loop() {}
+
+// Loop function
+void I2CManagerClass::checkForTimeout() {}
+
+
+#endif

IODevice.cpp

@@ -0,0 +1,504 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+
+#include <Arduino.h>
+#include "IODevice.h"
+#include "DIAG.h" 
+#include "FSH.h"
+#include "IO_MCP23017.h"
+
+#if defined(ARDUINO_ARCH_AVR) || defined(ARDUINO_ARCH_MEGAAVR)
+#define USE_FAST_IO
+#endif
+
+// Link to halSetup function.  If not defined, the function reference will be NULL.
+extern __attribute__((weak)) void halSetup();
+extern __attribute__((weak)) void mySetup();  // Deprecated function name, output warning if it's declared
+
+//==================================================================================================================
+// Static methods
+//------------------------------------------------------------------------------------------------------------------
+
+// Static functions
+
+// Static method to initialise the IODevice subsystem.  
+
+#if !defined(IO_NO_HAL)
+
+// Create any standard device instances that may be required, such as the Arduino pins 
+// and PCA9685.
+void IODevice::begin() {
+  // Initialise the IO subsystem
+  ArduinoPins::create(2, NUM_DIGITAL_PINS-2);  // Reserve pins for direct access
+  // Predefine two PCA9685 modules 0x40-0x41
+  // Allocates 32 pins 100-131
+  PCA9685::create(100, 16, 0x40);
+  PCA9685::create(116, 16, 0x41);
+  // Predefine two MCP23017 module 0x20/0x21
+  // Allocates 32 pins 164-195
+  MCP23017::create(164, 16, 0x20);
+  MCP23017::create(180, 16, 0x21);
+
+  // Call the begin() methods of each configured device in turn
+  for (IODevice *dev=_firstDevice; dev!=NULL; dev = dev->_nextDevice) {
+    dev->_begin();
+  }
+  _initPhase = false;
+
+  // Check for presence of deprecated mySetup() function, and output warning.
+  if (mySetup)
+    DIAG(F("WARNING: mySetup() function should be renamed to halSetup()"));
+
+  // Call user's halSetup() function (if defined in the build in myHal.cpp).
+  //  The contents will depend on the user's system hardware configuration.
+  //  The myHal.cpp file is a standard C++ module so has access to all of the DCC++EX APIs.
+  if (halSetup)
+    halSetup();
+}
+
+// Overarching static loop() method for the IODevice subsystem.  Works through the
+// list of installed devices and calls their individual _loop() method.
+// Devices may or may not implement this, but if they do it is useful for things like animations 
+// or flashing LEDs.
+// The current value of micros() is passed as a parameter, so the called loop function
+// doesn't need to invoke it.
+void IODevice::loop() {
+  unsigned long currentMicros = micros();
+  
+  IODevice *lastLoopDevice = _nextLoopDevice;  // So we know when to stop...
+  // Loop through devices until we find one ready to be serviced.
+  do {
+    if (!_nextLoopDevice) _nextLoopDevice = _firstDevice;
+    if (_nextLoopDevice) {
+      if (_nextLoopDevice->_deviceState != DEVSTATE_FAILED 
+            && ((long)(currentMicros - _nextLoopDevice->_nextEntryTime)) >= 0) {
+        // Found one ready to run, so invoke its _loop method.
+        _nextLoopDevice->_nextEntryTime = currentMicros;
+        _nextLoopDevice->_loop(currentMicros);
+        _nextLoopDevice = _nextLoopDevice->_nextDevice;
+        break;
+      }
+      // Not this one, move to next one
+      _nextLoopDevice = _nextLoopDevice->_nextDevice;
+    }
+  } while (_nextLoopDevice != lastLoopDevice); // Stop looking when we've done all.
+  
+  // Report loop time if diags enabled
+#if defined(DIAG_LOOPTIMES)
+  static unsigned long lastMicros = 0;
+  // Measure time since loop() method started.
+  unsigned long halElapsed = micros() - currentMicros;
+  // Measure time between loop() method entries.
+  unsigned long elapsed = currentMicros - lastMicros;
+  static unsigned long maxElapsed = 0, maxHalElapsed = 0;
+  static unsigned long lastOutputTime = 0;
+  static unsigned long halTotal = 0, total = 0;
+  static unsigned long count = 0;
+  const unsigned long interval = (unsigned long)5 * 1000 * 1000; // 5 seconds in microsec
+
+  // Ignore long loop counts while message is still outputting
+  if (currentMicros - lastOutputTime > 3000UL) {
+    if (elapsed > maxElapsed) maxElapsed = elapsed;
+    if (halElapsed > maxHalElapsed) maxHalElapsed = halElapsed;
+    halTotal += halElapsed;
+    total += elapsed;
+    count++;
+  }
+  if (currentMicros - lastOutputTime > interval) {
+    if (lastOutputTime > 0) 
+      DIAG(F("Loop Total:%lus (%lus max) HAL:%lus (%lus max)"), 
+        total/count, maxElapsed, halTotal/count, maxHalElapsed);
+    maxElapsed = maxHalElapsed = total = halTotal = count = 0;
+    lastOutputTime = currentMicros;
+  }
+  lastMicros = currentMicros;
+#endif
+}
+
+// Display a list of all the devices on the diagnostic stream.
+void IODevice::DumpAll() {
+  for (IODevice *dev = _firstDevice; dev != 0; dev = dev->_nextDevice) {
+    dev->_display();
+  }
+}
+
+// Determine if the specified vpin is allocated to a device.
+bool IODevice::exists(VPIN vpin) {
+  return findDevice(vpin) != NULL;
+}
+
+// check whether the pin supports notification.  If so, then regular _read calls are not required.
+bool IODevice::hasCallback(VPIN vpin) {
+  IODevice *dev = findDevice(vpin);
+  if (!dev) return false;
+  return dev->_hasCallback;
+}
+
+// Display (to diagnostics) details of the device.
+void IODevice::_display() {
+  DIAG(F("Unknown device Vpins:%d-%d %S"), 
+    (int)_firstVpin, (int)_firstVpin+_nPins-1, _deviceState==DEVSTATE_FAILED ? F("OFFLINE") : F(""));
+}
+
+// Find device associated with nominated Vpin and pass configuration values on to it.
+//   Return false if not found.
+bool IODevice::configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) {
+  IODevice *dev = findDevice(vpin);
+  if (dev) return dev->_configure(vpin, configType, paramCount, params);
+#ifdef DIAG_IO
+  DIAG(F("IODevice::configure(): Vpin ID %d not found!"), (int)vpin);
+#endif
+  return false;
+}
+
+// Read value from virtual pin.
+int IODevice::read(VPIN vpin) {
+  for (IODevice *dev = _firstDevice; dev != 0; dev = dev->_nextDevice) {
+    if (dev->owns(vpin)) 
+      return dev->_read(vpin);
+  }
+#ifdef DIAG_IO
+  DIAG(F("IODevice::read(): Vpin %d not found!"), (int)vpin);
+#endif
+  return false;
+}
+
+// Read analogue value from virtual pin.
+int IODevice::readAnalogue(VPIN vpin) {
+  for (IODevice *dev = _firstDevice; dev != 0; dev = dev->_nextDevice) {
+    if (dev->owns(vpin)) 
+      return dev->_readAnalogue(vpin);
+  }
+#ifdef DIAG_IO
+  DIAG(F("IODevice::readAnalogue(): Vpin %d not found!"), (int)vpin);
+#endif
+  return false;
+}
+
+// Write value to virtual pin(s).  If multiple devices are allocated the same pin
+//  then only the first one found will be used.
+void IODevice::write(VPIN vpin, int value) {
+  IODevice *dev = findDevice(vpin);
+  if (dev) {
+    dev->_write(vpin, value);
+    return;
+  }
+#ifdef DIAG_IO
+  DIAG(F("IODevice::write(): Vpin ID %d not found!"), (int)vpin);
+#endif
+}
+
+// Write analogue value to virtual pin(s).  If multiple devices are allocated
+// the same pin then only the first one found will be used.
+//
+// The significance of param1 and param2 may vary from device to device.
+// For servo controllers, param1 is the profile of the transition and param2
+// the duration, i.e. the time that the operation is to be animated over
+// in deciseconds (0-3276 sec)
+//
+void IODevice::writeAnalogue(VPIN vpin, int value, uint8_t param1, uint16_t param2) {
+  IODevice *dev = findDevice(vpin);
+  if (dev) {
+    dev->_writeAnalogue(vpin, value, param1, param2);
+    return;
+  }
+#ifdef DIAG_IO
+  DIAG(F("IODevice::writeAnalogue(): Vpin ID %d not found!"), (int)vpin);
+#endif
+}
+
+// isBusy, when called for a device pin is always a digital output or analogue output,
+//  returns input feedback state of the pin, i.e. whether the pin is busy performing
+//  an animation or fade over a period of time.
+bool IODevice::isBusy(VPIN vpin) {
+  IODevice *dev = findDevice(vpin);
+  if (dev) 
+    return dev->_read(vpin);
+  else
+    return false;
+}
+
+void IODevice::setGPIOInterruptPin(int16_t pinNumber) {
+  if (pinNumber >= 0)
+    pinMode(pinNumber, INPUT_PULLUP);
+  _gpioInterruptPin = pinNumber;
+}
+
+// Private helper function to add a device to the chain of devices.
+void IODevice::addDevice(IODevice *newDevice) {
+  // Link new object to the end of the chain.  Thereby, the first devices to be declared/created
+  // will be located faster by findDevice than those which are created later.
+  // Ideally declare/create the digital IO pins first, then servos, then more esoteric devices.
+  IODevice *lastDevice;
+  if (_firstDevice == 0)
+    _firstDevice = newDevice;
+  else {
+    for (IODevice *dev = _firstDevice; dev != 0; dev = dev->_nextDevice)
+      lastDevice = dev;
+    lastDevice->_nextDevice = newDevice;
+  }
+  newDevice->_nextDevice = 0;
+
+  // If the IODevice::begin() method has already been called, initialise device here.  If not,
+  // the device's _begin() method will be called by IODevice::begin().
+  if (!_initPhase)
+    newDevice->_begin();
+}
+
+// Private helper function to locate a device by VPIN.  Returns NULL if not found.
+//  This is performance-critical, so minimises the calculation and function calls necessary.
+IODevice *IODevice::findDevice(VPIN vpin) { 
+  for (IODevice *dev = _firstDevice; dev != 0; dev = dev->_nextDevice) {
+    VPIN firstVpin = dev->_firstVpin;
+    if (vpin >= firstVpin && vpin < firstVpin+dev->_nPins)
+      return dev;
+  }
+  return NULL;
+}
+  
+//==================================================================================================================
+// Static data
+//------------------------------------------------------------------------------------------------------------------
+
+// Chain of callback blocks (identifying registered callback functions for state changes)
+IONotifyCallback *IONotifyCallback::first = 0;
+
+// Start of chain of devices.
+IODevice *IODevice::_firstDevice = 0;
+
+// Reference to next device to be called on _loop() method.
+IODevice *IODevice::_nextLoopDevice = 0;
+
+// Flag which is reset when IODevice::begin has been called.
+bool IODevice::_initPhase = true;  
+
+
+//==================================================================================================================
+// Instance members
+//------------------------------------------------------------------------------------------------------------------
+
+// Method to check whether the id corresponds to this device
+bool IODevice::owns(VPIN id) {
+  return (id >= _firstVpin && id < _firstVpin + _nPins);
+}
+
+
+#else // !defined(IO_NO_HAL)
+
+// Minimal implementations of public HAL interface, to support Arduino pin I/O and nothing more.
+
+void IODevice::begin() { DIAG(F("NO HAL CONFIGURED!")); }
+bool IODevice::configure(VPIN pin, ConfigTypeEnum configType, int nParams, int p[]) {
+  if (configType!=CONFIGURE_INPUT || nParams!=1 || pin >= NUM_DIGITAL_PINS) return false;
+  #ifdef DIAG_IO
+  DIAG(F("Arduino _configurePullup Pin:%d Val:%d"), pin, p[0]);
+  #endif
+  pinMode(pin, p[0] ? INPUT_PULLUP : INPUT);
+  return true;
+}
+void IODevice::write(VPIN vpin, int value) {
+  if (vpin >= NUM_DIGITAL_PINS) return;
+  digitalWrite(vpin, value);
+  pinMode(vpin, OUTPUT);
+}
+void IODevice::writeAnalogue(VPIN, int, uint8_t, uint16_t) {}
+bool IODevice::isBusy(VPIN) { return false; }
+bool IODevice::hasCallback(VPIN) { return false; }
+int IODevice::read(VPIN vpin) { 
+  if (vpin >= NUM_DIGITAL_PINS) return 0;
+  return !digitalRead(vpin);  // Return inverted state (5v=0, 0v=1)
+}
+int IODevice::readAnalogue(VPIN vpin) {
+  pinMode(vpin, INPUT);
+  noInterrupts();
+  int value = analogRead(vpin);
+  interrupts();
+  return value;
+}
+void IODevice::loop() {}
+void IODevice::DumpAll() {
+  DIAG(F("NO HAL CONFIGURED!"));
+}
+bool IODevice::exists(VPIN vpin) { return (vpin > 2 && vpin < NUM_DIGITAL_PINS); }
+void IODevice::setGPIOInterruptPin(int16_t) {}
+
+// Chain of callback blocks (identifying registered callback functions for state changes)
+// Not used in IO_NO_HAL but must be declared.
+IONotifyCallback *IONotifyCallback::first = 0;
+
+#endif // IO_NO_HAL
+
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////
+
+// Constructor
+ArduinoPins::ArduinoPins(VPIN firstVpin, int nPins) {
+  _firstVpin = firstVpin;
+  _nPins = nPins;
+  int arrayLen = (_nPins+7)/8;
+  _pinPullups = (uint8_t *)calloc(3, arrayLen);
+  _pinModes = (&_pinPullups[0]) + arrayLen;
+  _pinInUse = (&_pinPullups[0]) + 2*arrayLen;
+  for (int i=0; i<arrayLen; i++) {
+    _pinPullups[i] = 0xff;  // default to pullup on, for inputs
+    _pinModes[i] = 0;
+    _pinInUse[i] = 0;
+  }
+}
+
+// Device-specific pin configuration.  Configure should be called infrequently so simplify 
+// code by using the standard pinMode function.
+bool ArduinoPins::_configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) {
+  if (configType != CONFIGURE_INPUT) return false;
+  if (paramCount != 1) return false;
+  bool pullup = params[0];
+
+  int pin = vpin;
+  #ifdef DIAG_IO
+  DIAG(F("Arduino _configurePullup Pin:%d Val:%d"), pin, pullup);
+  #endif
+  uint8_t mask = 1 << ((pin-_firstVpin) % 8);
+  uint8_t index = (pin-_firstVpin) / 8;
+  _pinModes[index] &= ~mask;  // set to input mode
+  if (pullup) {
+    _pinPullups[index] |= mask;
+    pinMode(pin, INPUT_PULLUP);
+  } else {
+    _pinPullups[index] &= ~mask;
+    pinMode(pin, INPUT);
+  }
+  _pinInUse[index] |= mask;
+  return true;
+}
+
+// Device-specific write function.
+void ArduinoPins::_write(VPIN vpin, int value) {
+  int pin = vpin;
+  #ifdef DIAG_IO
+  DIAG(F("Arduino Write Pin:%d Val:%d"), pin, value);
+  #endif
+  uint8_t mask = 1 << ((pin-_firstVpin) % 8);
+  uint8_t index = (pin-_firstVpin) / 8;
+  // First update the output state, then set into write mode if not already.
+  fastWriteDigital(pin, value);
+  if (!(_pinModes[index] & mask)) {
+    // Currently in read mode, change to write mode
+    _pinModes[index] |= mask;
+    // Since mode changes should be infrequent, use standard pinMode function
+    pinMode(pin, OUTPUT);
+    _pinInUse[index] |= mask;
+  }
+}
+
+// Device-specific read function (digital input).
+int ArduinoPins::_read(VPIN vpin) {
+  int pin = vpin;
+  uint8_t mask = 1 << ((pin-_firstVpin) % 8);
+  uint8_t index = (pin-_firstVpin) / 8;
+  if ((_pinModes[index] | ~_pinInUse[index]) & mask) {
+    // Currently in write mode or not initialised, change to read mode
+    _pinModes[index] &= ~mask;
+    // Since mode changes should be infrequent, use standard pinMode function
+    if (_pinPullups[index] & mask) 
+      pinMode(pin, INPUT_PULLUP);
+    else
+      pinMode(pin, INPUT);
+    _pinInUse[index] |= mask;
+  }
+  int value = !fastReadDigital(pin); // Invert (5v=0, 0v=1)
+
+  #ifdef DIAG_IO
+  //DIAG(F("Arduino Read Pin:%d Value:%d"), pin, value);
+  #endif
+  return value;
+}
+
+// Device-specific readAnalogue function (analogue input)
+int ArduinoPins::_readAnalogue(VPIN vpin) {
+  int pin = vpin;
+  uint8_t mask = 1 << ((pin-_firstVpin) % 8);
+  uint8_t index = (pin-_firstVpin) / 8;
+  if (_pinModes[index] & mask) {
+    // Currently in write mode, change to read mode
+    _pinModes[index] &= ~mask;
+    // Since mode changes should be infrequent, use standard pinMode function
+    if (_pinPullups[index] & mask) 
+      pinMode(pin, INPUT_PULLUP);
+    else
+      pinMode(pin, INPUT);
+  }
+
+  // Since AnalogRead is also called from interrupt code, disable interrupts 
+  // while we're using it.  There's only one ADC shared by all analogue inputs 
+  // on the Arduino, so we don't want interruptions.
+  //******************************************************************************
+  // NOTE: If the HAL is running on a computer without the DCC signal generator,
+  // then interrupts needn't be disabled.  Also, the DCC signal generator puts
+  // the ADC into fast mode, so if it isn't present, analogueRead calls will be much
+  // slower!!
+  //******************************************************************************
+  noInterrupts();
+  int value = analogRead(pin);
+  interrupts();
+
+  #ifdef DIAG_IO
+  DIAG(F("Arduino Read Pin:%d Value:%d"), pin, value);
+  #endif
+  return value;
+}
+
+void ArduinoPins::_display() {
+  DIAG(F("Arduino Vpins:%d-%d"), (int)_firstVpin, (int)_firstVpin+_nPins-1);
+}
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////
+
+
+void ArduinoPins::fastWriteDigital(uint8_t pin, uint8_t value) {
+#if defined(USE_FAST_IO)
+  if (pin >= NUM_DIGITAL_PINS) return;
+  uint8_t mask = digitalPinToBitMask(pin);
+  uint8_t port = digitalPinToPort(pin);
+  volatile uint8_t *outPortAdr = portOutputRegister(port);
+  noInterrupts();
+  if (value) 
+    *outPortAdr |= mask;
+  else
+    *outPortAdr &= ~mask;
+  interrupts();
+#else
+  digitalWrite(pin, value);
+#endif
+}
+
+bool ArduinoPins::fastReadDigital(uint8_t pin) {
+#if defined(USE_FAST_IO)
+  if (pin >= NUM_DIGITAL_PINS) return false;
+  uint8_t mask = digitalPinToBitMask(pin);
+  uint8_t port = digitalPinToPort(pin);
+  volatile uint8_t *inPortAdr = portInputRegister(port);
+  // read input
+  bool result = (*inPortAdr & mask) != 0;  
+#else
+  bool result = digitalRead(pin);
+#endif
+  return result;
+}
+

IODevice.h

@@ -0,0 +1,371 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef iodevice_h
+#define iodevice_h
+
+// Define symbol DIAG_IO to enable diagnostic output
+//#define DIAG_IO Y
+
+// Define symbol DIAG_LOOPTIMES to enable CS loop execution time to be reported
+//#define DIAG_LOOPTIMES
+
+// Define symbol IO_NO_HAL to reduce FLASH footprint when HAL features not required
+// The HAL is disabled by default on Nano and Uno platforms, because of limited flash space.
+#if defined(ARDUINO_AVR_NANO) || defined(ARDUINO_AVR_UNO) 
+#define IO_NO_HAL
+#endif
+
+// Define symbol IO_SWITCH_OFF_SERVO to set the PCA9685 output to 0 when an 
+// animation has completed.  This switches off the servo motor, preventing 
+// the continuous buzz sometimes found on servos, and reducing the 
+// power consumption of the servo when inactive.
+// It is recommended to enable this, unless it causes you problems.
+#define IO_SWITCH_OFF_SERVO
+
+#include "DIAG.h"
+#include "FSH.h"
+#include "I2CManager.h"
+#include "inttypes.h"
+
+typedef uint16_t VPIN;
+// Limit VPIN number to max 32767.  Above this number, printing often gives negative values.
+// This should be enough for 99% of users.
+#define VPIN_MAX 32767  
+#define VPIN_NONE 65535
+
+/* 
+ * Callback support for state change notification from an IODevice subclass to a 
+ * handler, e.g. Sensor object handling.
+ */
+
+class IONotifyCallback {
+public: 
+  typedef void IONotifyCallbackFunction(VPIN vpin, int value);
+  static void add(IONotifyCallbackFunction *function) {
+    IONotifyCallback *blk = new IONotifyCallback(function);
+    if (first) blk->next = first;
+    first = blk;
+  }
+  static void invokeAll(VPIN vpin, int value) {
+    for (IONotifyCallback *blk = first; blk != NULL; blk = blk->next)
+      blk->invoke(vpin, value);
+  }
+  static bool hasCallback() {
+    return first != NULL;
+  }
+private:
+  IONotifyCallback(IONotifyCallbackFunction *function) { invoke = function; };
+  IONotifyCallback *next = 0;
+  IONotifyCallbackFunction *invoke = 0;
+  static IONotifyCallback *first;
+};
+
+/*
+ * IODevice class
+ * 
+ * This class is the basis of the Hardware Abstraction Layer (HAL) for
+ * the DCC++EX Command Station.  All device classes derive from this.
+ * 
+ */
+
+class IODevice {
+public:
+
+  // Parameter values to identify type of call to IODevice::configure.
+  typedef enum : uint8_t {
+    CONFIGURE_INPUT = 1,
+    CONFIGURE_SERVO = 2,
+    CONFIGURE_OUTPUT = 3,
+  } ConfigTypeEnum;
+
+  typedef enum : uint8_t {
+    DEVSTATE_DORMANT = 0,
+    DEVSTATE_PROBING = 1,
+    DEVSTATE_INITIALISING = 2,
+    DEVSTATE_NORMAL = 3,
+    DEVSTATE_SCANNING = 4,
+    DEVSTATE_FAILED = 5,
+  } DeviceStateEnum;
+
+  // Static functions to find the device and invoke its member functions
+
+  // begin is invoked to create any standard IODevice subclass instances.
+  // Also, the _begin method of any existing instances is called from here.
+  static void begin();
+
+  // configure is used invoke an IODevice instance's _configure method
+  static bool configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]);
+
+  // User-friendly function for configuring an input pin.
+  inline static bool configureInput(VPIN vpin, bool pullupEnable) {
+    int params[] = {pullupEnable};
+    return IODevice::configure(vpin, CONFIGURE_INPUT, 1, params);
+  }
+
+  // User-friendly function for configuring a servo pin.
+  inline static bool configureServo(VPIN vpin, uint16_t activePosition, uint16_t inactivePosition, uint8_t profile=0, uint16_t duration=0, uint8_t initialState=0) {
+    int params[] = {(int)activePosition, (int)inactivePosition, profile, (int)duration, initialState};
+    return IODevice::configure(vpin, CONFIGURE_SERVO, 5, params);
+  }
+
+  // write invokes the IODevice instance's _write method.
+  static void write(VPIN vpin, int value);
+
+  // write invokes the IODevice instance's _writeAnalogue method (not applicable for digital outputs)
+  static void writeAnalogue(VPIN vpin, int value, uint8_t profile=0, uint16_t duration=0);
+
+  // isBusy returns true if the device is currently in an animation of some sort, e.g. is changing
+  //  the output over a period of time.
+  static bool isBusy(VPIN vpin);
+
+  // check whether the pin supports notification.  If so, then regular _read calls are not required.
+  static bool hasCallback(VPIN vpin);
+
+  // read invokes the IODevice instance's _read method.
+  static int read(VPIN vpin);
+
+  // read invokes the IODevice instance's _readAnalogue method.
+  static int readAnalogue(VPIN vpin);
+
+  // loop invokes the IODevice instance's _loop method.
+  static void loop();
+
+  static void DumpAll();
+
+  // exists checks whether there is a device owning the specified vpin
+  static bool exists(VPIN vpin);
+
+  // Enable shared interrupt on specified pin for GPIO extender modules.  The extender module
+  // should pull down this pin when requesting a scan.  The pin may be shared by multiple modules.
+  // Without the shared interrupt, input states are scanned periodically to detect changes on 
+  // GPIO extender pins.  If a shared interrupt pin is configured, then input states are scanned
+  // only when the shared interrupt pin is pulled low.  The external GPIO module releases the pin
+  // once the GPIO port concerned has been read.
+  void setGPIOInterruptPin(int16_t pinNumber);
+
+  
+protected:
+  
+  // Constructor
+  IODevice(VPIN firstVpin=0, int nPins=0) {
+    _firstVpin = firstVpin;
+    _nPins = nPins;
+    _nextEntryTime = 0;
+  }
+
+ // Method to perform initialisation of the device (optionally implemented within device class)
+  virtual void _begin() {}
+
+  // Method to configure device (optionally implemented within device class)
+  virtual bool _configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) { 
+    (void)vpin; (void)configType; (void)paramCount; (void)params; // Suppress compiler warning.
+    return false;
+  };
+
+  // Method to write new state (optionally implemented within device class)
+  virtual void _write(VPIN vpin, int value) {
+    (void)vpin; (void)value;
+  };
+
+  // Method to write an 'analogue' value (optionally implemented within device class)
+  virtual void _writeAnalogue(VPIN vpin, int value, uint8_t param1, uint16_t param2) {
+    (void)vpin; (void)value; (void) param1; (void)param2;
+  };
+
+  // Method to read digital pin state (optionally implemented within device class)
+  virtual int _read(VPIN vpin) { 
+    (void)vpin; 
+    return 0;
+  };
+
+  // Method to read analogue pin state (optionally implemented within device class)
+  virtual int _readAnalogue(VPIN vpin) { 
+    (void)vpin; 
+    return 0;
+  };
+
+  // Method to perform updates on an ongoing basis (optionally implemented within device class)
+  virtual void _loop(unsigned long currentMicros) {
+    delayUntil(currentMicros + 0x7fffffff); // Largest time in the future!  Effectively disable _loop calls.
+  };
+
+  // Method for displaying info on DIAG output (optionally implemented within device class)
+  virtual void _display();
+
+  // Destructor
+  virtual ~IODevice() {};
+
+  // Non-virtual function
+  void delayUntil(unsigned long futureMicrosCount) {
+    _nextEntryTime = futureMicrosCount;
+  }
+  
+  // Common object fields.
+  VPIN _firstVpin;
+  int _nPins;
+
+  // Flag whether the device supports callbacks.
+  bool _hasCallback = false;
+
+  // Pin number of interrupt pin for GPIO extender devices.  The extender module will pull this
+  //  pin low if an input changes state.
+  int16_t _gpioInterruptPin = -1;
+
+  // Static support function for subclass creation
+  static void addDevice(IODevice *newDevice);
+
+  // Current state of device
+  DeviceStateEnum _deviceState = DEVSTATE_DORMANT;
+
+private:
+  // Method to check whether the vpin corresponds to this device
+  bool owns(VPIN vpin);
+  // Method to find device handling Vpin
+  static IODevice *findDevice(VPIN vpin);
+
+  IODevice *_nextDevice = 0;
+  unsigned long _nextEntryTime;
+  static IODevice *_firstDevice;
+
+  static IODevice *_nextLoopDevice;
+  static bool _initPhase;
+};
+
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////
+/*
+ * IODevice subclass for PCA9685 16-channel PWM module.
+ */
+ 
+class PCA9685 : public IODevice {
+public:
+  static void create(VPIN vpin, int nPins, uint8_t I2CAddress);
+  // Constructor
+  PCA9685(VPIN vpin, int nPins, uint8_t I2CAddress);
+  enum ProfileType : uint8_t {
+    Instant = 0,  // Moves immediately between positions (if duration not specified)
+    UseDuration = 0, // Use specified duration
+    Fast = 1,     // Takes around 500ms end-to-end
+    Medium = 2,   // 1 second end-to-end
+    Slow = 3,     // 2 seconds end-to-end
+    Bounce = 4,   // For semaphores/turnouts with a bit of bounce!!
+    NoPowerOff = 0x80, // Flag to be ORed in to suppress power off after move.
+  };
+
+private:
+  // Device-specific initialisation
+  void _begin() override;
+  bool _configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) override;
+  // Device-specific write functions.
+  void _write(VPIN vpin, int value) override;
+  void _writeAnalogue(VPIN vpin, int value, uint8_t profile, uint16_t duration) override;
+  int _read(VPIN vpin) override; // returns the digital state or busy status of the device
+  void _loop(unsigned long currentMicros) override;
+  void updatePosition(uint8_t pin);
+  void writeDevice(uint8_t pin, int value);
+  void _display() override;
+
+  uint8_t _I2CAddress; // 0x40-0x43 possible
+
+  struct ServoData {
+    uint16_t activePosition : 12; // Config parameter
+    uint16_t inactivePosition : 12; // Config parameter
+    uint16_t currentPosition : 12;
+    uint16_t fromPosition : 12;
+    uint16_t toPosition : 12; 
+    uint8_t profile;  // Config parameter
+    uint16_t stepNumber; // Index of current step (starting from 0)
+    uint16_t numSteps;  // Number of steps in animation, or 0 if none in progress.
+    uint8_t currentProfile; // profile being used for current animation.
+    uint16_t duration; // time (tenths of a second) for animation to complete.
+  }; // 14 bytes per element, i.e. per pin in use
+  
+  struct ServoData *_servoData [16];
+
+  static const uint8_t _catchupSteps = 5; // number of steps to wait before switching servo off
+  static const byte FLASH _bounceProfile[30];
+
+  const unsigned int refreshInterval = 50; // refresh every 50ms
+
+  // structures for setting up non-blocking writes to servo controller
+  I2CRB requestBlock;
+  uint8_t outputBuffer[5];
+};
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////
+/*
+ * IODevice subclass for DCC accessory decoder.
+ */
+ 
+class DCCAccessoryDecoder: public IODevice {
+public:
+  static void create(VPIN firstVpin, int nPins, int DCCAddress, int DCCSubaddress);
+  // Constructor
+  DCCAccessoryDecoder(VPIN firstVpin, int nPins, int DCCAddress, int DCCSubaddress);
+
+private:
+  // Device-specific write function.
+  void _begin() override;
+  void _write(VPIN vpin, int value) override;
+  void _display() override;
+  int _packedAddress;
+};
+
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////
+/* 
+ *  IODevice subclass for arduino input/output pins.
+ */
+ 
+class ArduinoPins: public IODevice {
+public:
+  static void create(VPIN firstVpin, int nPins) {
+    addDevice(new ArduinoPins(firstVpin, nPins));
+  }
+  
+  // Constructor
+  ArduinoPins(VPIN firstVpin, int nPins);
+
+  static void fastWriteDigital(uint8_t pin, uint8_t value);
+  static bool fastReadDigital(uint8_t pin);
+
+private:
+  // Device-specific pin configuration
+  bool _configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) override;
+  // Device-specific write function.
+  void _write(VPIN vpin, int value) override;
+  // Device-specific read functions.
+  int _read(VPIN vpin) override;
+  int _readAnalogue(VPIN vpin) override;
+  void _display() override;
+
+
+  uint8_t *_pinPullups;
+  uint8_t *_pinModes; // each bit is 1 for output, 0 for input
+  uint8_t *_pinInUse; 
+};
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////
+
+#include "IO_MCP23008.h"
+#include "IO_MCP23017.h"
+#include "IO_PCF8574.h"
+
+#endif // iodevice_h

IO_AnalogueInputs.h

@@ -0,0 +1,165 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef io_analogueinputs_h
+#define io_analogueinputs_h
+
+// Uncomment following line to slow the scan cycle down to 1second ADC samples, with
+// diagnostic output of scanned values.
+//#define IO_ANALOGUE_SLOW
+
+#include "IODevice.h"
+#include "I2CManager.h"
+#include "DIAG.h"
+#include "FSH.h"
+
+/**********************************************************************************************
+ * ADS111x class for I2C-connected analogue input modules ADS1113, ADS1114 and ADS1115.
+ * 
+ * ADS1113 and ADS1114 are restricted to 1 input.  ADS1115 has a multiplexer which allows 
+ * any of four input pins to be read by its ADC.
+ * 
+ * The driver polls the device in accordance with the constant 'scanInterval' below.  On first loop
+ * entry, the multiplexer is set to pin A0 and the ADC is triggered.  On second and subsequent
+ * entries, the analogue value is read from the conversion register and then the multiplexer and
+ * ADC are set up to read the next pin.
+ * 
+ * The ADS111x is set up as follows:
+ *    Single-shot scan
+ *    Data rate 128 samples/sec (7.8ms/sample, but scanned every 10ms)
+ *    Comparator off
+ *    Gain FSR=6.144V
+ * The gain means that the maximum input voltage of 5V (when Vss=5V) gives a reading 
+ * of 32767*(5.0/6.144) = 26666.
+ * 
+ * A device is configured by the following:
+ *   ADS111x::create(firstVpin, nPins, i2cAddress);
+ * for example
+ *   ADS111x::create(300, 1, 0x48);  // single-input ADS1113
+ *   ADS111x::create(300, 4, 0x48);  // four-input ADS1115
+ * 
+ * Note: The device is simple and does not need initial configuration, so it should recover from
+ * temporary loss of communications or power.
+ **********************************************************************************************/
+class ADS111x: public IODevice { 
+public:
+  ADS111x(VPIN firstVpin, int nPins, uint8_t i2cAddress) {
+    _firstVpin = firstVpin;
+    _nPins = min(nPins,4);
+    _i2cAddress = i2cAddress;
+    _currentPin = 0;
+    for (int8_t i=0; i<_nPins; i++)
+      _value[i] = -1;
+    addDevice(this);
+  }
+  static void create(VPIN firstVpin, int nPins, uint8_t i2cAddress) {
+    new ADS111x(firstVpin, nPins, i2cAddress);
+  }
+private:
+  void _begin() {
+    // Initialise ADS device
+    if (I2CManager.exists(_i2cAddress)) {
+      _nextState = STATE_STARTSCAN;
+#ifdef DIAG_IO
+      _display();
+#endif
+    } else {
+      DIAG(F("ADS111x device not found, I2C:%x"), _i2cAddress);
+      _deviceState = DEVSTATE_FAILED;
+    }
+  }
+  void _loop(unsigned long currentMicros) override {
+
+    // Check that previous non-blocking write has completed, if not then wait
+    uint8_t status = _i2crb.status;
+    if (status == I2C_STATUS_PENDING) return;  // Busy, so don't do anything.
+    if (status == I2C_STATUS_OK) {
+      switch (_nextState) {
+        case STATE_STARTSCAN:
+          // Configure ADC and multiplexer for next scan.  See ADS111x datasheet for details
+          // of configuration register settings.
+          _outBuffer[0] = 0x01; // Config register address
+          _outBuffer[1] = 0xC0 + (_currentPin << 4); // Trigger single-shot, channel n
+          _outBuffer[2] = 0xA3;           // 250 samples/sec, comparator off
+          // Write command, without waiting for completion.
+          I2CManager.write(_i2cAddress, _outBuffer, 3, &_i2crb);
+
+          delayUntil(currentMicros + scanInterval);
+          _nextState = STATE_STARTREAD;
+          break;
+
+        case STATE_STARTREAD:
+          // Reading the pin value
+          _outBuffer[0] = 0x00;  // Conversion register address
+          I2CManager.read(_i2cAddress, _inBuffer, 2, _outBuffer, 1, &_i2crb); // Read register
+          _nextState = STATE_GETVALUE;
+          break;
+
+        case STATE_GETVALUE:
+          _value[_currentPin] = ((uint16_t)_inBuffer[0] << 8) + (uint16_t)_inBuffer[1];
+          #ifdef IO_ANALOGUE_SLOW
+          DIAG(F("ADS111x pin:%d value:%d"), _currentPin, _value[_currentPin]);
+          #endif
+
+          // Move to next pin
+          if (++_currentPin >= _nPins) _currentPin = 0;
+          _nextState = STATE_STARTSCAN;
+          break;
+        
+        default:
+          break;
+      }
+    } else { // error status
+      DIAG(F("ADS111x I2C:x%d Error:%d %S"), _i2cAddress, status, I2CManager.getErrorMessage(status));
+      _deviceState = DEVSTATE_FAILED;
+    }
+  }
+
+  int _readAnalogue(VPIN vpin) override {
+    int pin = vpin - _firstVpin;
+    return _value[pin];
+  }
+  
+  void _display() override {
+    DIAG(F("ADS111x I2C:x%x Configured on Vpins:%d-%d %S"), _i2cAddress, _firstVpin, _firstVpin+_nPins-1,
+      _deviceState == DEVSTATE_FAILED ? F("OFFLINE") : F(""));
+  }
+
+  // ADC conversion rate is 250SPS, or 4ms per conversion.  Set the period between updates to 10ms. 
+  // This is enough to allow the conversion to reliably complete in time.
+  #ifndef IO_ANALOGUE_SLOW
+  const unsigned long scanInterval = 10000UL;  // Period between successive ADC scans in microseconds.
+  #else
+  const unsigned long scanInterval = 1000000UL;  // Period between successive ADC scans in microseconds.
+  #endif
+  enum : uint8_t {
+    STATE_STARTSCAN,
+    STATE_STARTREAD, 
+    STATE_GETVALUE,
+  };
+  uint16_t _value[4];
+  uint8_t _i2cAddress;
+  uint8_t _outBuffer[3];
+  uint8_t _inBuffer[2];
+  uint8_t _currentPin;  // ADC pin currently being scanned
+  I2CRB _i2crb;
+  uint8_t _nextState;
+};
+
+#endif // io_analogueinputs_h

IO_DCCAccessory.cpp

@@ -0,0 +1,64 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "DCC.h"
+#include "IODevice.h"
+#include "DIAG.h"
+#include "defines.h"
+
+#define PACKEDADDRESS(addr, subaddr) (((addr) << 2)  + (subaddr))
+#define ADDRESS(packedaddr) ((packedaddr) >> 2)
+#define SUBADDRESS(packedaddr) ((packedaddr) % 4)
+
+void DCCAccessoryDecoder::create(VPIN vpin, int nPins, int DCCAddress, int DCCSubaddress) {
+  new DCCAccessoryDecoder(vpin, nPins, DCCAddress, DCCSubaddress);
+}
+
+// Constructors
+DCCAccessoryDecoder::DCCAccessoryDecoder(VPIN vpin, int nPins, int DCCAddress, int DCCSubaddress) {
+   _firstVpin = vpin;
+  _nPins = nPins;
+  _packedAddress = PACKEDADDRESS(DCCAddress, DCCSubaddress);
+  addDevice(this);
+}
+
+void DCCAccessoryDecoder::_begin() {
+#if defined(DIAG_IO)
+  _display();
+#endif
+}
+
+// Device-specific write function.  State 1=closed, 0=thrown.  Adjust for RCN-213 compliance
+void DCCAccessoryDecoder::_write(VPIN id, int state) {
+  int packedAddress = _packedAddress + id - _firstVpin;
+  #ifdef DIAG_IO
+  DIAG(F("DCC Write Linear Address:%d State:%d"), packedAddress, state);
+  #endif
+#if !defined(DCC_ACCESSORY_RCN_213)
+  state = !state;
+#endif
+  DCC::setAccessory(ADDRESS(packedAddress), SUBADDRESS(packedAddress), state);
+}
+
+void DCCAccessoryDecoder::_display() {
+  int endAddress = _packedAddress + _nPins - 1;
+  DIAG(F("DCCAccessoryDecoder Configured on Vpins:%d-%d Addresses %d/%d-%d/%d)"), _firstVpin, _firstVpin+_nPins-1,
+      ADDRESS(_packedAddress), SUBADDRESS(_packedAddress), ADDRESS(endAddress), SUBADDRESS(endAddress));
+}
+

IO_DFPlayer.h

@@ -0,0 +1,255 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*
+ * DFPlayer is an MP3 player module with an SD card holder.  It also has an integrated
+ * amplifier, so it only needs a power supply and a speaker.
+ * 
+ * This driver allows the device to be controlled through IODevice::write() and 
+ * IODevice::writeAnalogue() calls.
+ * 
+ * The driver is configured as follows:
+ * 
+ *       DFPlayer::create(firstVpin, nPins, Serialn);
+ * 
+ * Where firstVpin is the first vpin reserved for reading the device,
+ *       nPins is the number of pins to be allocated (max 5)
+ *   and Serialn is the name of the Serial port connected to the DFPlayer (e.g. Serial1).
+ * 
+ * Example:
+ *   In mySetup function within mySetup.cpp:
+ *       DFPlayer::create(3500, 5, Serial1);
+ * 
+ * Writing an analogue value 0-2999 to the first pin will select a numbered file from the SD card;
+ * Writing an analogue value 0-30 to the second pin will set the volume of the output;
+ * Writing a digital value to the first pin will play or stop the file;
+ * Reading a digital value from any pin will return true(1) if the player is playing, false(0) otherwise.
+ * 
+ * From EX-RAIL, the following commands may be used:
+ *   SET(3500)      -- starts playing the first file on the SD card
+ *   SET(3501)      -- starts playing the second file on the SD card
+ *   etc.
+ *   RESET(3500)    -- stops all playing on the player
+ *   WAITFOR(3500)  -- wait for the file currently being played by the player to complete
+ *   SERVO(3500,23,0)  -- plays file 23 at current volume
+ *   SERVO(3500,23,30)  -- plays file 23 at volume 30 (maximum)
+ *   SERVO(3501,20,0)   -- Sets the volume to 20
+ * 
+ * NB The DFPlayer's serial lines are not 5V safe, so connecting the Arduino TX directly 
+ * to the DFPlayer's RX terminal will cause lots of noise over the speaker, or worse.
+ * A 1k resistor in series with the module's RX terminal will alleviate this.
+ */
+
+#ifndef IO_DFPlayer_h
+#define IO_DFPlayer_h
+
+#include "IODevice.h"
+
+class DFPlayer : public IODevice {
+private: 
+  HardwareSerial *_serial;
+  bool _playing = false;
+  uint8_t _inputIndex = 0;
+  unsigned long _commandSendTime; // Allows timeout processing
+
+public:
+  // Constructor
+  DFPlayer(VPIN firstVpin, int nPins, HardwareSerial &serial) :
+    IODevice(firstVpin, nPins),
+    _serial(&serial) 
+  {
+    addDevice(this);
+  }
+
+  static void create(VPIN firstVpin, int nPins, HardwareSerial &serial) {
+    new DFPlayer(firstVpin, nPins, serial);
+  }
+
+protected:
+  void _begin() override {
+    _serial->begin(9600);
+    _deviceState = DEVSTATE_INITIALISING;
+
+    // Send a query to the device to see if it responds
+    sendPacket(0x42); 
+    _commandSendTime = micros();
+  }
+
+  void _loop(unsigned long currentMicros) override {
+    // Check for incoming data on _serial, and update busy flag accordingly.
+    // Expected message is in the form "7F FF 06 3D xx xx xx xx xx EF"
+    while (_serial->available()) {
+      int c = _serial->read();
+      if (c == 0x7E) 
+        _inputIndex = 1;
+      else if ((c==0xFF && _inputIndex==1)
+            || (c==0x3D && _inputIndex==3) 
+            || (_inputIndex >=4 && _inputIndex <= 8))
+        _inputIndex++;
+      else if (c==0x06 && _inputIndex==2) { 
+        // Valid message prefix, so consider the device online
+        if (_deviceState==DEVSTATE_INITIALISING) {
+          _deviceState = DEVSTATE_NORMAL;
+          #ifdef DIAG_IO
+          _display();
+          #endif
+        }
+        _inputIndex++;
+      } else if (c==0xEF && _inputIndex==9) {
+        // End of play
+        if (_playing) {
+          #ifdef DIAG_IO
+          DIAG(F("DFPlayer: Finished"));
+          #endif
+          _playing = false;
+        }
+        _inputIndex = 0;
+      } else 
+        _inputIndex = 0;  // Unrecognised character sequence, start again!
+    }
+    // Check if the initial prompt to device has timed out.  Allow 1 second
+    if (_deviceState == DEVSTATE_INITIALISING && currentMicros - _commandSendTime > 1000000UL) {
+      DIAG(F("DFPlayer device not responding on serial port"));
+      _deviceState = DEVSTATE_FAILED;
+    }
+    delayUntil(currentMicros + 10000); // Only enter every 10ms
+  }
+
+  // Write with value 1 starts playing a song.  The relative pin number is the file number.
+  // Write with value 0 stops playing.
+  void _write(VPIN vpin, int value) override {
+    int pin = vpin - _firstVpin;
+    if (value) {
+      // Value 1, start playing
+      #ifdef DIAG_IO
+      DIAG(F("DFPlayer: Play %d"), pin+1);
+      #endif
+      sendPacket(0x03, pin+1);
+      _playing = true;
+    } else {
+      // Value 0, stop playing
+      #ifdef DIAG_IO
+      DIAG(F("DFPlayer: Stop"));
+      #endif
+      sendPacket(0x16);
+      _playing = false;
+    }
+  }
+
+  // WriteAnalogue on first pin uses the nominated value as a file number to start playing, if file number > 0.
+  // Volume may be specified as second parameter to writeAnalogue.
+  // If value is zero, the player stops playing.  
+  // WriteAnalogue on second pin sets the output volume.
+  void _writeAnalogue(VPIN vpin, int value, uint8_t volume=0, uint16_t=0) override { 
+    uint8_t pin = vpin - _firstVpin;
+ 
+    // Validate parameter.
+    volume = min(30,volume);
+
+    if (pin == 0) {
+      // Play track 
+      if (value > 0) {
+        #ifdef DIAG_IO
+        DIAG(F("DFPlayer: Play %d"), value);
+        #endif
+        sendPacket(0x03, value); // Play track
+        _playing = true;
+        if (volume > 0) {
+          #ifdef DIAG_IO
+          DIAG(F("DFPlayer: Volume %d"), volume);
+          #endif
+          sendPacket(0x06, volume);  // Set volume
+        }
+      } else {
+        #ifdef DIAG_IO
+        DIAG(F("DFPlayer: Stop"));
+        #endif
+        sendPacket(0x16); // Stop play
+        _playing = false;
+      }
+    } else if (pin == 1) {
+      // Set volume (0-30)
+      if (value > 30) value = 30;
+      else if (value < 0) value = 0;
+      #ifdef DIAG_IO
+      DIAG(F("DFPlayer: Volume %d"), value);
+      #endif
+      sendPacket(0x06, value);      
+    }
+  }
+
+  // A read on any pin indicates whether the player is still playing.
+  int _read(VPIN) override {
+    return _playing;
+  }
+
+  void _display() override {
+    DIAG(F("DFPlayer Configured on Vpins:%d-%d %S"), _firstVpin, _firstVpin+_nPins-1,
+      (_deviceState==DEVSTATE_FAILED) ? F("OFFLINE") : F(""));
+  }
+  
+private:
+  // 7E FF 06 0F 00 01 01 xx xx EF
+  // 0	->	7E is start code
+  // 1	->	FF is version
+  // 2	->	06 is length
+  // 3	->	0F is command
+  // 4	->	00 is no receive
+  // 5~6	->	01 01 is argument
+  // 7~8	->	checksum = 0 - ( FF+06+0F+00+01+01 )
+  // 9	->	EF is end code
+
+  void sendPacket(uint8_t command, uint16_t arg = 0)
+  {
+    uint8_t out[] = { 0x7E,
+        0xFF,
+        06,
+        command,
+        00,
+        static_cast<uint8_t>(arg >> 8),
+        static_cast<uint8_t>(arg & 0x00ff),
+        00,
+        00,
+        0xEF };
+
+    setChecksum(out);
+
+    _serial->write(out, sizeof(out));
+  }
+
+  uint16_t calcChecksum(uint8_t* packet)
+  {
+    uint16_t sum = 0;
+    for (int i = 1; i < 7; i++)
+    {
+      sum += packet[i];
+    }
+    return -sum;
+  }
+
+  void setChecksum(uint8_t* out)
+  {
+    uint16_t sum = calcChecksum(out);
+
+    out[7] = (sum >> 8);
+    out[8] = (sum & 0xff);
+  }
+};
+
+#endif // IO_DFPlayer_h

IO_ExampleSerial.cpp

@@ -0,0 +1,129 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <Arduino.h>
+#include "IO_ExampleSerial.h"
+#include "FSH.h"
+
+// Constructor
+IO_ExampleSerial::IO_ExampleSerial(VPIN firstVpin, int nPins, HardwareSerial *serial, unsigned long baud) {
+  _firstVpin = firstVpin;
+  _nPins = nPins;
+  _pinValues = (uint16_t *)calloc(_nPins, sizeof(uint16_t));
+  _baud = baud;
+  
+  // Save reference to serial port driver
+  _serial = serial;
+
+  addDevice(this);
+}
+
+// Static create method for one module.
+void IO_ExampleSerial::create(VPIN firstVpin, int nPins, HardwareSerial *serial, unsigned long baud) {
+  new IO_ExampleSerial(firstVpin, nPins, serial, baud);
+}
+
+// Device-specific initialisation
+void IO_ExampleSerial::_begin() {
+  _serial->begin(_baud);
+#if defined(DIAG_IO)
+  _display();
+#endif
+
+  // Send a few # characters to the output
+  for (uint8_t i=0; i<3; i++)
+    _serial->write('#');
+}
+
+// Device-specific write function.  Write a string in the form "#Wm,n#"
+//  where m is the vpin number, and n is the value.
+void IO_ExampleSerial::_write(VPIN vpin, int value) {
+  int pin = vpin -_firstVpin;
+  #ifdef DIAG_IO
+  DIAG(F("IO_ExampleSerial::_write Pin:%d Value:%d"), (int)vpin, value);
+  #endif
+  // Send a command string over the serial line
+  _serial->print('#');
+  _serial->print('W');
+  _serial->print(pin);
+  _serial->print(',');
+  _serial->print(value);
+  _serial->println('#');
+  DIAG(F("ExampleSerial Sent command, p1=%d, p2=%d"), vpin, value);
+ }
+
+// Device-specific read function.
+int IO_ExampleSerial::_read(VPIN vpin) {
+
+  // Return a value for the specified vpin.
+  int result = _pinValues[vpin-_firstVpin];
+
+  return result;
+}
+
+// Loop function to do background scanning of the input port.  State 
+//  machine parses the incoming command as it is received.  Command
+//  is in the form "#Nm,n#" where m is the index and n is the value.
+void IO_ExampleSerial::_loop(unsigned long currentMicros) {
+  (void)currentMicros;  // Suppress compiler warnings
+  if (_serial->available()) {
+    // Input data available to read.  Read a character.
+    char c = _serial->read();
+    switch (_inputState) {
+      case 0: // Waiting for start of command
+        if (c == '#')  // Start of command received.
+          _inputState = 1;
+        break;
+      case 1: // Expecting command character
+        if (c == 'N') { // 'Notify' character received
+          _inputState = 2;
+          _inputValue = _inputIndex = 0;
+        } else
+          _inputState = 0; // Unexpected char, reset
+        break;
+      case 2: // reading first parameter (index)
+        if (isdigit(c))
+          _inputIndex = _inputIndex * 10 + (c-'0');
+        else if (c==',') 
+          _inputState = 3;
+        else
+          _inputState = 0; // Unexpected char, reset
+        break;
+      case 3: // reading reading second parameter (value)
+        if (isdigit(c)) 
+          _inputValue = _inputValue * 10 - (c-'0');
+        else if (c=='#') { // End of command
+          // Complete command received, do something with it.
+          DIAG(F("ExampleSerial Received command, p1=%d, p2=%d"), _inputIndex, _inputValue);
+          if (_inputIndex < _nPins) { // Store value
+            _pinValues[_inputIndex] = _inputValue;
+          }
+          _inputState = 0; // Done, start again.
+        } else
+          _inputState = 0; // Unexpected char, reset
+        break;
+    }
+  }
+}
+
+void IO_ExampleSerial::_display() {
+  DIAG(F("IO_ExampleSerial Configured on VPins:%d-%d"), (int)_firstVpin, 
+    (int)_firstVpin+_nPins-1);
+}
+

IO_ExampleSerial.h

@@ -0,0 +1,58 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*
+ * To declare a device instance, 
+ *    IO_ExampleSerial myDevice(1000, 10, Serial3, 9600);
+ * or to create programmatically,
+ *    IO_ExampleSerial::create(1000, 10, Serial3, 9600);
+ * 
+ * (uses VPINs 1000-1009, talke on Serial 3 at 9600 baud.)
+ * 
+ * See IO_ExampleSerial.cpp for the protocol used over the serial line.
+ * 
+ */
+
+#ifndef IO_EXAMPLESERIAL_H
+#define IO_EXAMPLESERIAL_H
+
+#include "IODevice.h"
+
+class IO_ExampleSerial : public IODevice {
+public:
+  IO_ExampleSerial(VPIN firstVpin, int nPins, HardwareSerial *serial, unsigned long baud);
+  static void create(VPIN firstVpin, int nPins, HardwareSerial *serial, unsigned long baud);  
+
+protected:
+  void _begin() override;
+  void _loop(unsigned long currentMicros) override;
+  void _write(VPIN vpin, int value) override;
+  int _read(VPIN vpin) override;
+  void _display() override;
+
+private:
+  HardwareSerial *_serial;
+  uint8_t _inputState = 0;
+  int _inputIndex = 0;
+  int _inputValue = 0;
+  uint16_t *_pinValues; // Pointer to block of memory containing pin values
+  unsigned long _baud;
+};
+
+#endif // IO_EXAMPLESERIAL_H

IO_GPIOBase.h

@@ -0,0 +1,249 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef IO_GPIOBASE_H
+#define IO_GPIOBASE_H
+
+#include "IODevice.h"
+#include "I2CManager.h"
+#include "DIAG.h"
+
+// GPIOBase is defined as a class template.  This allows it to be instantiated by
+// subclasses with different types, according to the number of pins on the GPIO module.
+// For example, GPIOBase<uint8_t> for 8 pins, GPIOBase<uint16_t> for 16 pins etc.
+// A module with up to 64 pins can be handled in this way (uint64_t).
+
+template <class T>
+class GPIOBase : public IODevice {
+
+protected:
+  // Constructor
+  GPIOBase(FSH *deviceName, VPIN firstVpin, uint8_t nPins, uint8_t I2CAddress, int interruptPin);
+  // Device-specific initialisation
+  void _begin() override;
+  // Device-specific pin configuration function.  
+  bool _configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) override;
+  // Pin write function.
+  void _write(VPIN vpin, int value) override;
+  // Pin read function.
+  int _read(VPIN vpin) override;
+  void _display() override;
+  void _loop(unsigned long currentMicros) override;
+
+  // Data fields
+  uint8_t _I2CAddress; 
+  // Allocate enough space for all input pins
+  T _portInputState; 
+  T _portOutputState;
+  T _portMode;
+  T _portPullup;
+  T _portInUse;
+  // Interval between refreshes of each input port
+  static const int _portTickTime = 4000;
+
+  // Virtual functions for interfacing with I2C GPIO Device
+  virtual void _writeGpioPort() = 0;
+  virtual void _readGpioPort(bool immediate=true) = 0;
+  virtual void _writePullups() {};
+  virtual void _writePortModes() {};
+  virtual void _setupDevice() {};
+  virtual void _processCompletion(uint8_t status) {
+    (void)status; // Suppress compiler warning
+  };
+
+  I2CRB requestBlock;
+  FSH *_deviceName;
+};
+
+// Because class GPIOBase is a template, the implementation (below) must be contained within the same
+// file as the class declaration (above).  Otherwise it won't compile!
+
+// Constructor
+template <class T>
+GPIOBase<T>::GPIOBase(FSH *deviceName, VPIN firstVpin, uint8_t nPins, uint8_t I2CAddress, int interruptPin) :
+  IODevice(firstVpin, nPins)
+{
+  _deviceName = deviceName;
+  _I2CAddress = I2CAddress;
+  _gpioInterruptPin = interruptPin;
+  _hasCallback = true;
+  // Add device to list of devices.
+  addDevice(this);
+}
+
+template <class T>
+void GPIOBase<T>::_begin() {
+  // Configure pin used for GPIO extender notification of change (if allocated)
+  if (_gpioInterruptPin >= 0) 
+    pinMode(_gpioInterruptPin, INPUT_PULLUP);
+
+  I2CManager.begin();
+  I2CManager.setClock(400000);
+  if (I2CManager.exists(_I2CAddress)) {
+#if defined(DIAG_IO)
+    _display();
+#endif
+    _portMode = 0;  // default to input mode
+    _portPullup = -1; // default to pullup enabled
+    _portInputState = -1;
+    _portInUse = 0;
+    _setupDevice();
+    _deviceState = DEVSTATE_NORMAL;
+  } else {
+    DIAG(F("%S I2C:x%x Device not detected"), _deviceName, _I2CAddress);
+    _deviceState = DEVSTATE_FAILED;
+  }
+}
+
+// Configuration parameters for inputs: 
+//  params[0]: enable pullup
+//  params[1]: invert input (optional)
+template <class T>
+bool GPIOBase<T>::_configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) {
+  if (configType != CONFIGURE_INPUT) return false;
+  if (paramCount == 0 || paramCount > 1) return false;
+  bool pullup = params[0];
+  int pin = vpin - _firstVpin;
+  #ifdef DIAG_IO
+  DIAG(F("%S I2C:x%x Config Pin:%d Val:%d"), _deviceName, _I2CAddress, pin, pullup);
+  #endif
+  uint16_t mask = 1 << pin;
+  if (pullup) 
+    _portPullup |= mask;
+  else
+    _portPullup &= ~mask;
+  // Mark that port has been accessed
+  _portInUse |= mask;
+  // Set input mode
+  _portMode &= ~mask;
+
+  // Call subclass's virtual function to write to device
+  _writePortModes();
+  _writePullups();
+  // Port change will be notified on next loop entry.
+
+  return true;
+}
+
+// Periodically read the input port
+template <class T>
+void GPIOBase<T>::_loop(unsigned long currentMicros) {
+  T lastPortStates = _portInputState;
+  if (_deviceState == DEVSTATE_SCANNING && !requestBlock.isBusy()) {
+    uint8_t status = requestBlock.status;
+    if (status == I2C_STATUS_OK) {
+      _deviceState = DEVSTATE_NORMAL;
+    } else {
+      _deviceState = DEVSTATE_FAILED;
+      DIAG(F("%S I2C:x%x Error:%d %S"), _deviceName, _I2CAddress, status, 
+        I2CManager.getErrorMessage(status));
+    }
+    _processCompletion(status);
+  // Set unused pin and write mode pin value to 1
+    _portInputState |= ~_portInUse | _portMode;
+
+    // Scan for changes in input states and invoke callback (if present)
+    T differences = lastPortStates ^ _portInputState;
+    if (differences && IONotifyCallback::hasCallback()) {
+      // Scan for differences bit by bit
+      T mask = 1;
+      for (int pin=0; pin<_nPins; pin++) {
+        if (differences & mask) {
+          // Change detected.
+          IONotifyCallback::invokeAll(_firstVpin+pin, (_portInputState & mask) == 0);
+        }
+        mask <<= 1;
+      }
+    }
+
+    #ifdef DIAG_IO
+    if (differences)
+      DIAG(F("%S I2C:x%x PortStates:%x"), _deviceName, _I2CAddress, _portInputState);
+    #endif
+  }
+
+  // Check if interrupt configured.  If not, or if it is active (pulled down), then
+  //  initiate a scan.
+  if (_gpioInterruptPin < 0 || !digitalRead(_gpioInterruptPin)) {
+    // TODO: Could suppress reads if there are no pins configured as inputs!
+
+    // Read input
+    if (_deviceState == DEVSTATE_NORMAL) {
+      _readGpioPort(false);  // Initiate non-blocking read
+      _deviceState= DEVSTATE_SCANNING;
+    }
+  }
+  // Delay next entry until tick elapsed.
+  delayUntil(currentMicros + _portTickTime);
+}
+
+template <class T>
+void GPIOBase<T>::_display() {
+  DIAG(F("%S I2C:x%x Configured on Vpins:%d-%d %S"), _deviceName, _I2CAddress, 
+    _firstVpin, _firstVpin+_nPins-1, (_deviceState==DEVSTATE_FAILED) ? F("OFFLINE") : F(""));
+}
+
+template <class T>
+void GPIOBase<T>::_write(VPIN vpin, int value) {
+  int pin = vpin - _firstVpin;
+  T mask = 1 << pin;
+  #ifdef DIAG_IO
+  DIAG(F("%S I2C:x%x Write Pin:%d Val:%d"), _deviceName, _I2CAddress, pin, value);
+  #endif
+
+  // Set port mode output if currently not output mode
+  if (!(_portMode & mask)) {
+    _portInUse |= mask;
+    _portMode |= mask;
+    _writePortModes();
+  }
+
+  // Update port output state
+  if (value) 
+    _portOutputState |= mask;
+  else
+    _portOutputState &= ~mask;
+
+  // Call subclass's virtual function to write to device.
+  return _writeGpioPort();
+}
+
+template <class T>
+int GPIOBase<T>::_read(VPIN vpin) {
+  int pin = vpin - _firstVpin;
+  T mask = 1 << pin;
+
+  // Set port mode to input if currently output or first use
+  if ((_portMode | ~_portInUse) & mask) {
+    _portMode &= ~mask;
+    _portInUse |= mask;
+    _writePullups();
+    _writePortModes();
+    // Port won't have been read yet, so read it now.
+    _readGpioPort();
+  // Set unused pin and write mode pin value to 1
+    _portInputState |= ~_portInUse | _portMode;
+    #ifdef DIAG_IO
+    DIAG(F("%S I2C:x%x PortStates:%x"), _deviceName, _I2CAddress, _portInputState);
+    #endif
+  }
+  return (_portInputState & mask) ? 0 : 1;  // Invert state (5v=0, 0v=1)
+}
+
+#endif

IO_HCSR04.h

@@ -0,0 +1,188 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*
+ * The HC-SR04 module has an ultrasonic transmitter (40kHz) and a receiver.
+ * It is operated through two signal pins.  When the transmit pin is set to 1
+ * for 10us, on the falling edge the transmitter sends a short transmission of
+ * 8 pulses (like a sonar 'ping').  This is reflected off objects and received
+ * by the receiver.  A pulse is sent on the receive pin whose length is equal
+ * to the delay between the transmission of the pulse and the detection of
+ * its echo.  The distance of the reflecting object is calculated by halving
+ * the time (to allow for the out and back distance), then multiplying by the
+ * speed of sound (assumed to be constant).
+ *
+ * This driver polls the HC-SR04 by sending the trigger pulse and then measuring
+ * the length of the received pulse.  If the calculated distance is less than
+ * the threshold, the output state returned by a read() call changes to 1.  If
+ * the distance is greater than the threshold plus a hysteresis margin, the
+ * output changes to 0. The device also supports readAnalogue(), which returns
+ * the measured distance in cm, or 32767 if the distance exceeds the
+ * offThreshold.
+ *
+ * It might be thought that the measurement would be more reliable if interrupts
+ * were disabled while the pulse is being timed.  However, this would affect
+ * other functions in the CS so the measurement is being performed with
+ * interrupts enabled.  Also, we could use an interrupt pin in the Arduino for
+ * the timing, but the same consideration applies.  In any case, the DCC
+ * interrupt occurs once every 58us, so any IRC code is much faster than that.
+ * And 58us corresponds to 1cm in the calculation, so the effect of
+ * interrupts is negligible.
+ *
+ * Note: The timing accuracy required for measuring the pulse length means that
+ * the pins have to be direct Arduino pins; GPIO pins on an IO Extender cannot
+ * provide the required accuracy.
+ */
+
+#ifndef IO_HCSR04_H
+#define IO_HCSR04_H
+
+#include "IODevice.h"
+
+class HCSR04 : public IODevice {
+
+private:
+  // pins must be arduino GPIO pins, not extender pins or HAL pins.
+  int _trigPin = -1;
+  int _echoPin = -1;
+  // Thresholds for setting active state in cm.
+  uint8_t _onThreshold;  // cm
+  uint8_t _offThreshold; // cm
+  // Last measured distance in cm.
+  uint16_t _distance;
+  // Active=1/inactive=0 state 
+  uint8_t _value = 0;
+  // Factor for calculating the distance (cm) from echo time (ms).
+  //  Based on a speed of sound of 345 metres/second.
+  const uint16_t factor = 58; // ms/cm
+
+public:
+  // Constructor perfroms static initialisation of the device object
+  HCSR04 (VPIN vpin, int trigPin, int echoPin, uint16_t onThreshold, uint16_t offThreshold) {
+    _firstVpin = vpin;
+    _nPins = 1;
+    _trigPin = trigPin;
+    _echoPin = echoPin;
+    _onThreshold = onThreshold;
+    _offThreshold = offThreshold;
+    addDevice(this);
+  }
+
+  // Static create function provides alternative way to create object
+  static void create(VPIN vpin, int trigPin, int echoPin, uint16_t onThreshold, uint16_t offThreshold) {
+    new HCSR04(vpin, trigPin, echoPin, onThreshold, offThreshold);
+  }
+
+protected:
+  // _begin function called to perform dynamic initialisation of the device
+  void _begin() override {
+    pinMode(_trigPin, OUTPUT);
+    pinMode(_echoPin, INPUT);
+    ArduinoPins::fastWriteDigital(_trigPin, 0);
+#if defined(DIAG_IO)
+    _display();
+#endif
+  }
+
+  // _read function - just return _value (calculated in _loop).
+  int _read(VPIN vpin) override {
+    (void)vpin;  // avoid compiler warning
+    return _value;
+  }
+
+  int _readAnalogue(VPIN vpin) override {
+    (void)vpin; // avoid compiler warning
+    return _distance;
+  }
+
+  // _loop function - read HC-SR04 once every 50 milliseconds.
+  void _loop(unsigned long currentMicros) override {
+    read_HCSR04device();
+    // Delay next loop entry until 50ms have elapsed.
+    delayUntil(currentMicros + 50000UL);
+  }
+
+  void _display() override {
+    DIAG(F("HCSR04 Configured on Vpin:%d TrigPin:%d EchoPin:%d On:%dcm Off:%dcm"),
+      _firstVpin, _trigPin, _echoPin, _onThreshold, _offThreshold);
+  }
+
+private:
+  // This polls the HC-SR04 device by sending a pulse and measuring the duration of
+  //  the pulse observed on the receive pin.  In order to be kind to the rest of the CS
+  //  software, no interrupts are used and interrupts are not disabled.  The pulse duration
+  //  is measured in a loop, using the micros() function.  Therefore, interrupts from other
+  //  sources may affect the result.  However, interrupts response code in CS typically takes
+  //  much less than the 58us frequency for the DCC interrupt, and 58us corresponds to only 1cm
+  //  in the HC-SR04.
+  //  To reduce chatter on the output, hysteresis is applied on reset: the output is set to 1 when the 
+  //  measured distance is less than the onThreshold, and is set to 0 if the measured distance is
+  //  greater than the offThreshold.
+  //
+  void read_HCSR04device() {
+    // uint16 enough to time up to 65ms
+    uint16_t startTime, waitTime, currentTime, maxTime;  
+
+    // If receive pin is still set on from previous call, abort the read.
+    if (ArduinoPins::fastReadDigital(_echoPin))
+      return;
+
+    // Send 10us pulse to trigger transmitter
+    ArduinoPins::fastWriteDigital(_trigPin, 1);
+    delayMicroseconds(10);
+    ArduinoPins::fastWriteDigital(_trigPin, 0);
+
+    // Wait for receive pin to be set
+    startTime = currentTime = micros();
+    maxTime = factor * _offThreshold * 2;
+    while (!ArduinoPins::fastReadDigital(_echoPin)) {
+      // lastTime = currentTime;
+      currentTime = micros();
+      waitTime = currentTime - startTime;
+      if (waitTime > maxTime) {
+        // Timeout waiting for pulse start, abort the read
+        return;
+      }
+    }
+
+    // Wait for receive pin to reset, and measure length of pulse
+    startTime = currentTime = micros();
+    maxTime = factor * _offThreshold;
+    while (ArduinoPins::fastReadDigital(_echoPin)) {
+      currentTime = micros();
+      waitTime = currentTime - startTime;
+      // If pulse is too long then set return value to zero,
+      //  and finish without waiting for end of pulse.
+      if (waitTime > maxTime) {
+        // Pulse length longer than maxTime, reset value.
+        _value = 0;
+        _distance = 32767;
+        return;
+      }
+    } 
+    // Check if pulse length is below threshold, if so set value.
+    //DIAG(F("HCSR04: Pulse Len=%l Distance=%d"), waitTime, distance);
+    _distance = waitTime / factor; // in centimetres
+    if (_distance < _onThreshold) 
+      _value = 1;
+  }
+
+};
+
+#endif //IO_HCSR04_H

IO_MCP23008.h

@@ -0,0 +1,106 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef IO_MCP23008_H
+#define IO_MCP23008_H
+
+#include "IO_GPIOBase.h"
+
+#if defined(ARDUINO_ARCH_ESP32) // min seems to be missing from that package
+#ifndef min
+#define min(a,b) ((a)<(b)?(a):(b))
+#endif
+#endif
+
+class MCP23008 : public GPIOBase<uint8_t> {
+public:
+  static void create(VPIN firstVpin, uint8_t nPins, uint8_t I2CAddress, int interruptPin=-1) {
+    new MCP23008(firstVpin, nPins, I2CAddress, interruptPin);
+  }
+
+  // Constructor
+  MCP23008(VPIN firstVpin, uint8_t nPins, uint8_t I2CAddress, int interruptPin=-1)
+    : GPIOBase<uint8_t>((FSH *)F("MCP23008"), firstVpin, min(nPins, 8), I2CAddress, interruptPin) {
+
+    requestBlock.setRequestParams(_I2CAddress, inputBuffer, sizeof(inputBuffer),
+      outputBuffer, sizeof(outputBuffer));
+    outputBuffer[0] = REG_GPIO;
+  }
+  
+private:
+  void _writeGpioPort() override {
+    I2CManager.write(_I2CAddress, 2, REG_GPIO, _portOutputState);
+  }
+  void _writePullups() override {
+    // Set pullups only for in-use pins.  This prevents pullup being set for a pin that
+    //  is intended for use as an output but hasn't been written to yet.
+    I2CManager.write(_I2CAddress, 2, REG_GPPU, _portPullup & _portInUse);  
+  }
+  void _writePortModes() override {
+    // Write 0 to IODIR for in-use pins that are outputs, 1 for others.
+    uint8_t temp = ~(_portMode & _portInUse);
+    I2CManager.write(_I2CAddress, 2, REG_IODIR, temp);
+    // Enable interrupt-on-change for in-use pins that are inputs (_portMode=0)
+    temp = ~_portMode & _portInUse;
+    I2CManager.write(_I2CAddress, 2, REG_INTCON, 0x00);
+    I2CManager.write(_I2CAddress, 2, REG_GPINTEN, temp);
+  }
+  void _readGpioPort(bool immediate) override {
+    if (immediate) {
+      uint8_t buffer;
+      I2CManager.read(_I2CAddress, &buffer, 1, 1, REG_GPIO);
+      _portInputState = buffer;
+    } else {
+      // Queue new request
+      requestBlock.wait(); // Wait for preceding operation to complete
+      // Issue new request to read GPIO register
+      I2CManager.queueRequest(&requestBlock);
+    }
+  }
+  // This function is invoked when an I/O operation on the requestBlock completes.
+  void _processCompletion(uint8_t status) override {
+    if (status == I2C_STATUS_OK) 
+      _portInputState = inputBuffer[0];
+    else  
+      _portInputState = 0xff;
+  }
+  void _setupDevice() override {
+    // IOCON is set ODR=1 (open drain shared interrupt pin), INTPOL=0 (active-Low)
+    I2CManager.write(_I2CAddress, 2, REG_IOCON, 0x04);
+    _writePortModes();
+    _writePullups();
+    _writeGpioPort();
+  }
+ 
+  uint8_t inputBuffer[1];
+  uint8_t outputBuffer[1];
+
+  enum {
+    // Register definitions for MCP23008
+    REG_IODIR=0x00,
+    REG_GPINTEN=0x02,
+    REG_INTCON=0x04,
+    REG_IOCON=0x05,
+    REG_GPPU=0x06,
+    REG_GPIO=0x09,
+  };
+
+};
+
+#endif

IO_MCP23017.h

@@ -0,0 +1,112 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef io_mcp23017_h
+#define io_mcp23017_h
+
+#include "IO_GPIOBase.h"
+#include "FSH.h"
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////
+/*
+ * IODevice subclass for MCP23017 16-bit I/O expander.
+ */
+ 
+class MCP23017 : public GPIOBase<uint16_t> {
+public:
+  static void create(VPIN vpin, int nPins, uint8_t I2CAddress, int interruptPin=-1) {
+    new MCP23017(vpin, min(nPins,16), I2CAddress, interruptPin);
+  }
+  
+  // Constructor
+  MCP23017(VPIN vpin, int nPins, uint8_t I2CAddress, int interruptPin=-1) 
+    : GPIOBase<uint16_t>((FSH *)F("MCP23017"), vpin, nPins, I2CAddress, interruptPin) 
+  {
+    requestBlock.setRequestParams(_I2CAddress, inputBuffer, sizeof(inputBuffer),
+      outputBuffer, sizeof(outputBuffer));
+    outputBuffer[0] = REG_GPIOA;
+  }
+
+private:
+  void _writeGpioPort() override {
+    I2CManager.write(_I2CAddress, 3, REG_GPIOA, _portOutputState, _portOutputState>>8);
+  }
+  void _writePullups() override {
+    // Set pullups only for in-use pins.  This prevents pullup being set for a pin that
+    //  is intended for use as an output but hasn't been written to yet.
+    uint16_t temp = _portPullup & _portInUse;
+    I2CManager.write(_I2CAddress, 3, REG_GPPUA, temp, temp>>8);  
+  }
+  void _writePortModes() override {
+    // Write 0 to IODIR for in-use pins that are outputs, 1 for others.
+    uint16_t temp = ~(_portMode & _portInUse);
+    I2CManager.write(_I2CAddress, 3, REG_IODIRA, temp, temp>>8);
+    // Enable interrupt for in-use pins which are inputs (_portMode=0)
+    temp = ~_portMode & _portInUse;
+    I2CManager.write(_I2CAddress, 3, REG_INTCONA, 0x00, 0x00);
+    I2CManager.write(_I2CAddress, 3, REG_GPINTENA, temp, temp>>8);
+  }
+  void _readGpioPort(bool immediate) override {
+    if (immediate) {
+      uint8_t buffer[2];
+      I2CManager.read(_I2CAddress, buffer, 2, 1, REG_GPIOA);
+      _portInputState = ((uint16_t)buffer[1]<<8) | buffer[0];
+    } else {
+      // Queue new request
+      requestBlock.wait(); // Wait for preceding operation to complete
+      // Issue new request to read GPIO register
+      I2CManager.queueRequest(&requestBlock);
+    }
+  }
+  // This function is invoked when an I/O operation on the requestBlock completes.
+  void _processCompletion(uint8_t status) override {
+    if (status == I2C_STATUS_OK) 
+      _portInputState = ((uint16_t)inputBuffer[1]<<8) | inputBuffer[0];
+    else  
+      _portInputState = 0xffff;
+  }
+
+  void _setupDevice() override {
+    // IOCON is set MIRROR=1, ODR=1 (open drain shared interrupt pin)
+    I2CManager.write(_I2CAddress, 2, REG_IOCON, 0x44);
+    _writePortModes();
+    _writePullups();
+    _writeGpioPort();
+  }
+ 
+  uint8_t inputBuffer[2];
+  uint8_t outputBuffer[1];
+ 
+  enum {
+    REG_IODIRA = 0x00,
+    REG_IODIRB = 0x01,
+    REG_GPINTENA = 0x04,
+    REG_GPINTENB = 0x05,
+    REG_INTCONA = 0x08,
+    REG_INTCONB = 0x09,
+    REG_IOCON = 0x0A,
+    REG_GPPUA = 0x0C,
+    REG_GPPUB = 0x0D,
+    REG_GPIOA = 0x12,
+    REG_GPIOB = 0x13,
+  };
+
+};
+
+#endif

IO_PCA9685.cpp

@@ -0,0 +1,274 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "IODevice.h"
+#include "I2CManager.h"
+#include "DIAG.h"
+
+// REGISTER ADDRESSES
+static const byte PCA9685_MODE1=0x00;      // Mode Register 
+static const byte PCA9685_FIRST_SERVO=0x06;  /** low byte first servo register ON*/
+static const byte PCA9685_PRESCALE=0xFE;     /** Prescale register for PWM output frequency */
+// MODE1 bits
+static const byte MODE1_SLEEP=0x10;   /**< Low power mode. Oscillator off */
+static const byte MODE1_AI=0x20;      /**< Auto-Increment enabled */
+static const byte MODE1_RESTART=0x80; /**< Restart enabled */
+
+static const float FREQUENCY_OSCILLATOR=25000000.0; /** Accurate enough for our purposes  */
+static const uint8_t PRESCALE_50HZ = (uint8_t)(((FREQUENCY_OSCILLATOR / (50.0 * 4096.0)) + 0.5) - 1);
+static const uint32_t MAX_I2C_SPEED = 1000000L; // PCA9685 rated up to 1MHz I2C clock speed
+
+// Predeclare helper function
+static void writeRegister(byte address, byte reg, byte value);
+
+// Create device driver instance.
+void PCA9685::create(VPIN firstVpin, int nPins, uint8_t I2CAddress) {
+  new PCA9685(firstVpin, nPins, I2CAddress);
+}
+
+// Configure a port on the PCA9685.
+bool PCA9685::_configure(VPIN vpin, ConfigTypeEnum configType, int paramCount, int params[]) {
+  if (configType != CONFIGURE_SERVO) return false;
+  if (paramCount != 5) return false;
+  #ifdef DIAG_IO
+  DIAG(F("PCA9685 Configure VPIN:%d Apos:%d Ipos:%d Profile:%d Duration:%d state:%d"), 
+    vpin, params[0], params[1], params[2], params[3], params[4]);
+  #endif
+
+  int8_t pin = vpin - _firstVpin;
+  struct ServoData *s = _servoData[pin];
+  if (s == NULL) { 
+    _servoData[pin] = (struct ServoData *)calloc(1, sizeof(struct ServoData));
+    s = _servoData[pin];
+    if (!s) return false; // Check for failed memory allocation
+  }
+
+  s->activePosition = params[0];
+  s->inactivePosition = params[1];
+  s->profile = params[2];
+  s->duration = params[3];
+  int state = params[4];
+
+  if (state != -1) {
+    // Position servo to initial state
+    _writeAnalogue(vpin, state ? s->activePosition : s->inactivePosition, 0, 0);
+  } 
+  return true;
+}
+
+// Constructor
+PCA9685::PCA9685(VPIN firstVpin, int nPins, uint8_t I2CAddress) {
+  _firstVpin = firstVpin;
+  _nPins = min(nPins, 16);
+  _I2CAddress = I2CAddress;
+  // To save RAM, space for servo configuration is not allocated unless a pin is used.
+  // Initialise the pointers to NULL.
+  for (int i=0; i<_nPins; i++)
+    _servoData[i] = NULL;
+
+  addDevice(this);
+
+  // Initialise structure used for setting pulse rate
+  requestBlock.setWriteParams(_I2CAddress, outputBuffer, sizeof(outputBuffer));
+}
+
+// Device-specific initialisation
+void PCA9685::_begin() {
+  I2CManager.begin();
+  I2CManager.setClock(1000000); // Nominally able to run up to 1MHz on I2C
+          // In reality, other devices including the Arduino will limit 
+          // the clock speed to a lower rate.
+
+  // Initialise I/O module here.
+  if (I2CManager.exists(_I2CAddress)) {
+    writeRegister(_I2CAddress, PCA9685_MODE1, MODE1_SLEEP | MODE1_AI);    
+    writeRegister(_I2CAddress, PCA9685_PRESCALE, PRESCALE_50HZ);   // 50Hz clock, 20ms pulse period.
+    writeRegister(_I2CAddress, PCA9685_MODE1, MODE1_AI);
+    writeRegister(_I2CAddress, PCA9685_MODE1, MODE1_RESTART | MODE1_AI);
+    // In theory, we should wait 500us before sending any other commands to each device, to allow
+    // the PWM oscillator to get running.  However, we don't do any specific wait, as there's 
+    // plenty of other stuff to do before we will send a command.
+  #if defined(DIAG_IO)
+    _display();
+  #endif
+  } else
+    _deviceState = DEVSTATE_FAILED;
+}
+
+// Device-specific write function, invoked from IODevice::write().  
+// For this function, the configured profile is used.
+void PCA9685::_write(VPIN vpin, int value) {
+  if (_deviceState == DEVSTATE_FAILED) return;
+  #ifdef DIAG_IO
+  DIAG(F("PCA9685 Write Vpin:%d Value:%d"), vpin, value);
+  #endif
+  int pin = vpin - _firstVpin;
+  if (value) value = 1;
+
+  struct ServoData *s = _servoData[pin];
+  if (s != NULL) {
+    // Use configured parameters
+    _writeAnalogue(vpin, value ? s->activePosition : s->inactivePosition, s->profile, s->duration);
+  } // else { /* ignorethe request */ }
+}
+
+// Device-specific writeAnalogue function, invoked from IODevice::writeAnalogue().
+// Profile is as follows:
+//  Bit 7:     0=Set PWM to 0% to power off servo motor when finished
+//             1=Keep PWM pulses on (better when using PWM to drive an LED)
+//  Bits 6-0:  0           Use specified duration (defaults to 0 deciseconds)
+//             1 (Fast)    Move servo in 0.5 seconds
+//             2 (Medium)  Move servo in 1.0 seconds
+//             3 (Slow)    Move servo in 2.0 seconds
+//             4 (Bounce)  Servo 'bounces' at extremes.
+//            
+void PCA9685::_writeAnalogue(VPIN vpin, int value, uint8_t profile, uint16_t duration) {
+  if (_deviceState == DEVSTATE_FAILED) return;
+  #ifdef DIAG_IO
+  DIAG(F("PCA9685 WriteAnalogue Vpin:%d Value:%d Profile:%d Duration:%d"), 
+    vpin, value, profile, duration);
+  #endif
+  int pin = vpin - _firstVpin;
+  if (value > 4095) value = 4095;
+  else if (value < 0) value = 0;
+
+  struct ServoData *s = _servoData[pin];
+  if (s == NULL) {
+    // Servo pin not configured, so configure now using defaults
+    s = _servoData[pin] = (struct ServoData *) calloc(sizeof(struct ServoData), 1);
+    if (s == NULL) return;  // Check for memory allocation failure
+    s->activePosition = 0;
+    s->inactivePosition = 0;
+    s->currentPosition = value;
+    s->profile = Instant;  // Use instant profile (but not this time)
+  }
+
+  // Animated profile.  Initiate the appropriate action.
+  s->currentProfile = profile;
+  uint8_t profileValue = profile & ~NoPowerOff;  // Mask off 'don't-power-off' bit.
+  s->numSteps = profileValue==Fast ? 10 :   // 0.5 seconds
+                profileValue==Medium ? 20 : // 1.0 seconds
+                profileValue==Slow ? 40 :   // 2.0 seconds
+                profileValue==Bounce ? sizeof(_bounceProfile)-1 : // ~ 1.5 seconds
+                duration * 2 + 1; // Convert from deciseconds (100ms) to refresh cycles (50ms)
+  s->stepNumber = 0;
+  s->toPosition = value;
+  s->fromPosition = s->currentPosition;
+}
+
+// _read returns true if the device is currently in executing an animation, 
+//  changing the output over a period of time.
+int PCA9685::_read(VPIN vpin) {
+  if (_deviceState == DEVSTATE_FAILED) return 0;
+  int pin = vpin - _firstVpin;
+  struct ServoData *s = _servoData[pin];
+  if (s == NULL) 
+    return false; // No structure means no animation!
+  else
+    return (s->stepNumber < s->numSteps);
+}
+
+void PCA9685::_loop(unsigned long currentMicros) {
+  for (int pin=0; pin<_nPins; pin++) {
+    updatePosition(pin);
+  }
+  delayUntil(currentMicros + refreshInterval * 1000UL);
+}
+
+// Private function to reposition servo
+// TODO: Could calculate step number from elapsed time, to allow for erratic loop timing.
+void PCA9685::updatePosition(uint8_t pin) {
+  struct ServoData *s = _servoData[pin];
+  
+  if (s == NULL) return; // No pin configuration/state data
+
+  if (s->numSteps == 0) return; // No animation in progress
+
+  if (s->stepNumber == 0 && s->fromPosition == s->toPosition) {
+    // Go straight to end of sequence, output final position.
+    s->stepNumber = s->numSteps-1;
+  }
+
+  if (s->stepNumber < s->numSteps) {
+    // Animation in progress, reposition servo
+    s->stepNumber++;
+    if ((s->currentProfile & ~NoPowerOff) == Bounce) {
+      // Retrieve step positions from array in flash
+      byte profileValue = GETFLASH(&_bounceProfile[s->stepNumber]);
+      s->currentPosition = map(profileValue, 0, 100, s->fromPosition, s->toPosition);
+    } else {
+      // All other profiles - calculate step by linear interpolation between from and to positions.
+      s->currentPosition = map(s->stepNumber, 0, s->numSteps, s->fromPosition, s->toPosition);
+    }
+    // Send servo command
+    writeDevice(pin, s->currentPosition);
+  } else if (s->stepNumber < s->numSteps + _catchupSteps) {
+    // We've finished animation, wait a little to allow servo to catch up
+    s->stepNumber++;
+  } else if (s->stepNumber == s->numSteps + _catchupSteps 
+            && s->currentPosition != 0) {
+#ifdef IO_SWITCH_OFF_SERVO
+    if ((s->currentProfile & NoPowerOff) == 0) {
+      // Wait has finished, so switch off PWM to prevent annoying servo buzz
+      writeDevice(pin, 0);
+    }
+#endif
+    s->numSteps = 0;  // Done now.
+  }
+}
+
+// writeDevice takes a pin in range 0 to _nPins-1 within the device, and a value
+// between 0 and 4095 for the PWM mark-to-period ratio, with 4095 being 100%.
+void PCA9685::writeDevice(uint8_t pin, int value) {
+  #ifdef DIAG_IO
+  DIAG(F("PCA9685 I2C:x%x WriteDevice Pin:%d Value:%d"), _I2CAddress, pin, value);
+  #endif
+  // Wait for previous request to complete
+  uint8_t status = requestBlock.wait();
+  if (status != I2C_STATUS_OK) {
+    _deviceState = DEVSTATE_FAILED;
+    DIAG(F("PCA9685 I2C:x%x failed %S"), _I2CAddress, I2CManager.getErrorMessage(status));
+  } else {
+    // Set up new request.
+    outputBuffer[0] = PCA9685_FIRST_SERVO + 4 * pin;
+    outputBuffer[1] = 0;
+    outputBuffer[2] = (value == 4095 ? 0x10 : 0);  // 4095=full on
+    outputBuffer[3] = value & 0xff;
+    outputBuffer[4] = value >> 8;
+    I2CManager.queueRequest(&requestBlock);
+  }
+}
+
+// Display details of this device.
+void PCA9685::_display() {
+  DIAG(F("PCA9685 I2C:x%x Configured on Vpins:%d-%d %S"), _I2CAddress, (int)_firstVpin, 
+    (int)_firstVpin+_nPins-1, (_deviceState==DEVSTATE_FAILED) ? F("OFFLINE") : F(""));
+}
+
+// Internal helper function for this device
+static void writeRegister(byte address, byte reg, byte value) {
+  I2CManager.write(address, 2, reg, value);
+}
+
+// Profile for a bouncing signal or turnout
+// The profile below is in the range 0-100% and should be combined with the desired limits
+// of the servo set by _activePosition and _inactivePosition.  The profile is symmetrical here,
+// i.e. the bounce is the same on the down action as on the up action.  First entry isn't used.
+const byte FLASH PCA9685::_bounceProfile[30] = 
+    {0,2,3,7,13,33,50,83,100,83,75,70,65,60,60,65,74,84,100,83,75,70,70,72,75,80,87,92,97,100};

IO_PCF8574.h

@@ -0,0 +1,102 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/* 
+ * The PCF8574 is a simple device; it only has one register.  The device 
+ * input/output mode and pullup are configured through this, and the 
+ * output state is written and the input state read through it too.
+ * 
+ * This is accomplished by having a weak resistor in series with the output,
+ * and a read-back of the other end of the resistor.  As an output, the 
+ * pin state is set to 1 or 0, and the output voltage goes to +5V or 0V
+ * (through the weak resistor).
+ * 
+ * In order to use the pin as an input, the output is written as
+ * a '1' in order to pull up the resistor.  Therefore the input will be
+ * 1 unless the pin is pulled down externally, in which case it will be 0.
+ * 
+ * As a consequence of this approach, it is not possible to use the device for
+ * inputs without pullups.
+ */
+
+#ifndef IO_PCF8574_H
+#define IO_PCF8574_H
+
+#include "IO_GPIOBase.h"
+
+class PCF8574 : public GPIOBase<uint8_t> {
+public:
+  static void create(VPIN firstVpin, uint8_t nPins, uint8_t I2CAddress, int interruptPin=-1) {
+    new PCF8574(firstVpin, nPins, I2CAddress, interruptPin);
+  }
+
+  PCF8574(VPIN firstVpin, uint8_t nPins, uint8_t I2CAddress, int interruptPin=-1)
+    : GPIOBase<uint8_t>((FSH *)F("PCF8574"), firstVpin, min(nPins, 8), I2CAddress, interruptPin) 
+  {
+    requestBlock.setReadParams(_I2CAddress, inputBuffer, 1);
+  }
+  
+private:
+  // The pin state is '1' if the pin is an input or if it is an output set to 1.  Zero otherwise. 
+  void _writeGpioPort() override {
+    I2CManager.write(_I2CAddress, 1, _portOutputState | ~_portMode);
+  }
+
+  // The PCF8574 handles inputs by applying a weak pull-up when output is driven to '1'.
+  // Therefore, writing '1' in _writePortModes is enough to set the module to input mode 
+  // and enable pull-up.
+  void _writePullups() override { }
+
+  // The pin state is '1' if the pin is an input or if it is an output set to 1.  Zero otherwise. 
+  void _writePortModes() override {
+    I2CManager.write(_I2CAddress, 1, _portOutputState | ~_portMode);
+  }
+
+  // In immediate mode, _readGpioPort reads the device GPIO port and updates _portInputState accordingly.
+  //  When not in immediate mode, it initiates a request using the request block and returns.
+  //  When the request completes, _processCompletion finishes the operation.
+  void _readGpioPort(bool immediate) override {
+    if (immediate) {
+      uint8_t buffer[1];
+      I2CManager.read(_I2CAddress, buffer, 1);
+      _portInputState = buffer[0];
+    } else {
+      requestBlock.wait(); // Wait for preceding operation to complete
+      // Issue new request to read GPIO register
+      I2CManager.queueRequest(&requestBlock);
+    }
+  }
+
+  // This function is invoked when an I/O operation on the requestBlock completes.
+  void _processCompletion(uint8_t status) override {
+    if (status == I2C_STATUS_OK) 
+      _portInputState = inputBuffer[0];
+    else  
+      _portInputState = 0xff; 
+  }
+
+  // Set up device ports
+  void _setupDevice() override { 
+    _writePortModes();
+  }
+ 
+  uint8_t inputBuffer[1];
+};
+
+#endif

IO_VL53L0X.h

@@ -0,0 +1,299 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  
+ *  This file is part of DCC++EX API
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/*
+ * The VL53L0X Time-Of-Flight sensor operates by sending a short laser pulse and detecting
+ * the reflection of the pulse.  The time between the pulse and the receipt of reflections
+ * is measured and used to determine the distance to the reflecting object.
+ * 
+ * For economy of memory and processing time, this driver includes only part of the code 
+ * that ST provide in their API.  Also, the API code isn't very clear and it is not easy
+ * to identify what operations are useful and what are not. 
+ * The operation shown here doesn't include any calibration, so is probably not as accurate
+ * as using the full driver, but it's probably accurate enough for the purpose.
+ * 
+ * The device driver allocates up to 3 vpins to the device.  A digital read on the first pin
+ * will return a value that indicates whether the object is within the threshold range (1)
+ * or not (0).  An analogue read on the first pin returns the last measured distance (in mm), 
+ * the second pin returns the signal strength, and the third pin returns detected 
+ * ambient light level.  By default the device takes around 60ms to complete a ranging 
+ * operation, so we do a 100ms cycle (10 samples per second).
+ * 
+ * The VL53L0X is initially set to respond to I2C address 0x29.  If you only have one module,
+ * you can use this address.  However, the address can be modified by software.  If
+ * you select another address, that address will be written to the device and used until the device is reset.
+ * 
+ * If you have more than one module, then you will need to specify a digital VPIN (Arduino
+ * digital output or I/O extender pin) which you connect to the module's XSHUT pin.  Now,
+ * when the device driver starts, the XSHUT pin is set LOW to turn the module off.  Once 
+ * all VL53L0X modules are turned off, the driver works through each module in turn by
+ * setting XSHUT to HIGH to turn the module on,, then writing the module's desired I2C address.
+ * In this way, many VL53L0X modules can be connected to the one I2C bus, each one 
+ * using a distinct I2C address.
+ * 
+ * WARNING:  If the device's XSHUT pin is not connected, then it is very prone to noise, 
+ * and the device may even reset when handled.  If you're not using XSHUT, then it's 
+ * best to tie it to +5V.
+ * 
+ * The driver is configured as follows:
+ * 
+ * Single VL53L0X module:
+ *      VL53L0X::create(firstVpin, nPins, i2cAddress, lowThreshold, highThreshold);
+ * Where firstVpin is the first vpin reserved for reading the device,
+ *       nPins is 1, 2 or 3,
+ *       i2cAddress is the address of the device (normally 0x29),
+ *       lowThreshold is the distance at which the digital vpin state is set to 1 (in mm),
+ *   and highThreshold is the distance at which the digital vpin state is set to 0 (in mm).
+ * 
+ * Multiple VL53L0X modules:
+ *       VL53L0X::create(firstVpin, nPins, i2cAddress, lowThreshold, highThreshold, xshutPin);
+ *       ...
+ * Where firstVpin is the first vpin reserved for reading the device,
+ *       nPins is 1, 2 or 3,
+ *       i2cAddress is the address of the device (any valid address except 0x29),
+ *       lowThreshold is the distance at which the digital vpin state is set to 1 (in mm),
+ *       highThreshold is the distance at which the digital vpin state is set to 0 (in mm),
+ *   and xshutPin is the VPIN number corresponding to a digital output that is connected to the
+ *       XSHUT terminal on the module.
+ * 
+ * Example:
+ *   In mySetup function within mySetup.cpp:
+ *      VL53L0X::create(4000, 3, 0x29, 200, 250);
+ *      Sensor::create(4000, 4000, 0);  // Create a sensor
+ * 
+ *   When an object comes within 200mm of the sensor, a message 
+ *      <Q 4000>
+ *   will be sent over the serial USB, and when the object moves more than 250mm from the sensor, 
+ *   a message
+ *      <q 4000>
+ *   will be sent. 
+ * 
+ */
+
+#ifndef IO_VL53L0X_h
+#define IO_VL53L0X_h
+
+#include "IODevice.h"
+
+class VL53L0X : public IODevice {
+private: 
+  uint8_t _i2cAddress;
+  uint16_t _ambient;
+  uint16_t _distance;
+  uint16_t _signal;
+  uint16_t _onThreshold;
+  uint16_t _offThreshold;
+  VPIN _xshutPin;
+  bool _value;
+  uint8_t _nextState = 0;
+  I2CRB _rb;
+  uint8_t _inBuffer[12];
+  uint8_t _outBuffer[2];
+  // State machine states.
+  enum : uint8_t {
+    STATE_INIT = 0,
+    STATE_CONFIGUREADDRESS = 1,
+    STATE_SKIP = 2,
+    STATE_CONFIGUREDEVICE = 3,
+    STATE_INITIATESCAN = 4,
+    STATE_CHECKSTATUS = 5,
+    STATE_GETRESULTS = 6,
+    STATE_DECODERESULTS = 7,
+  };
+
+  // Register addresses
+  enum : uint8_t {
+    VL53L0X_REG_SYSRANGE_START=0x00,
+    VL53L0X_REG_RESULT_INTERRUPT_STATUS=0x13,
+    VL53L0X_REG_RESULT_RANGE_STATUS=0x14,
+    VL53L0X_CONFIG_PAD_SCL_SDA__EXTSUP_HV=0x89,
+    VL53L0X_REG_I2C_SLAVE_DEVICE_ADDRESS=0x8A,
+  };
+  const uint8_t VL53L0X_I2C_DEFAULT_ADDRESS=0x29;
+
+public:
+  VL53L0X(VPIN firstVpin, int nPins, uint8_t i2cAddress, uint16_t onThreshold, uint16_t offThreshold, VPIN xshutPin = VPIN_NONE) {
+    _firstVpin = firstVpin;
+    _nPins = min(nPins, 3);
+    _i2cAddress = i2cAddress;
+    _onThreshold = onThreshold;
+    _offThreshold = offThreshold;
+    _xshutPin = xshutPin;
+    _value = 0;
+    addDevice(this);
+  }
+  static void create(VPIN firstVpin, int nPins, uint8_t i2cAddress, uint16_t onThreshold, uint16_t offThreshold, VPIN xshutPin = VPIN_NONE) {
+    new VL53L0X(firstVpin, nPins, i2cAddress, onThreshold, offThreshold, xshutPin);
+  }
+
+protected:
+  void _begin() override {
+    if (_xshutPin == VPIN_NONE) {
+      // Check if device is already responding on the nominated address.
+      if (I2CManager.exists(_i2cAddress)) {
+        // Yes, it's already on this address, so skip the address initialisation.
+        _nextState = STATE_CONFIGUREDEVICE;
+      } else {
+        _nextState = STATE_INIT;
+      }
+    }
+  }
+
+  void _loop(unsigned long currentMicros) override {
+    uint8_t status;
+    switch (_nextState) {
+      case STATE_INIT:
+        // On first entry to loop, reset this module by pulling XSHUT low.  All modules
+        // will be reset in turn.
+        if (_xshutPin != VPIN_NONE) IODevice::write(_xshutPin, 0);
+        _nextState = STATE_CONFIGUREADDRESS;
+        break;
+      case STATE_CONFIGUREADDRESS:
+        // On second entry, set XSHUT pin high to allow the module to restart.
+        // On the module, there is a diode in series with the XSHUT pin to 
+        // protect the low-voltage pin against +5V.
+        if (_xshutPin != VPIN_NONE) IODevice::write(_xshutPin, 1);
+        // Allow the module time to restart
+        delay(10);
+        // Then write the desired I2C address to the device, while this is the only
+        //  module responding to the default address.
+        I2CManager.write(VL53L0X_I2C_DEFAULT_ADDRESS, 2, VL53L0X_REG_I2C_SLAVE_DEVICE_ADDRESS, _i2cAddress);
+        _nextState = STATE_SKIP;
+        break;
+      case STATE_SKIP:
+        // Do nothing on the third entry.
+        _nextState = STATE_CONFIGUREDEVICE;
+        break;
+      case STATE_CONFIGUREDEVICE:
+        // On next entry, check if device address has been set.
+        if (I2CManager.exists(_i2cAddress)) {
+          #ifdef DIAG_IO
+          _display();
+          #endif
+          // Set 2.8V mode
+          write_reg(VL53L0X_CONFIG_PAD_SCL_SDA__EXTSUP_HV, 
+            read_reg(VL53L0X_CONFIG_PAD_SCL_SDA__EXTSUP_HV) | 0x01);
+        } else {
+          DIAG(F("VL53L0X I2C:x%x device not responding"), _i2cAddress);
+          _deviceState = DEVSTATE_FAILED;
+        }
+        _nextState = STATE_INITIATESCAN;
+        break;
+      case STATE_INITIATESCAN:
+        // Not scanning, so initiate a scan
+        _outBuffer[0] = VL53L0X_REG_SYSRANGE_START;
+        _outBuffer[1] = 0x01;
+        I2CManager.write(_i2cAddress, _outBuffer, 2, &_rb);
+        _nextState = STATE_CHECKSTATUS;
+        break;
+      case STATE_CHECKSTATUS:
+        status = _rb.status;
+        if (status == I2C_STATUS_PENDING) return; // try next time
+        if (status != I2C_STATUS_OK) {
+          DIAG(F("VL53L0X I2C:x%x Error:%d %S"), _i2cAddress, status, I2CManager.getErrorMessage(status));
+          _deviceState = DEVSTATE_FAILED;
+          _value = false;
+        } else
+          _nextState = 2;
+        delayUntil(currentMicros + 95000); // wait for 95 ms before checking.
+        _nextState = STATE_GETRESULTS;
+        break;
+      case STATE_GETRESULTS:
+        // Ranging completed.  Request results
+        _outBuffer[0] = VL53L0X_REG_RESULT_RANGE_STATUS;
+        I2CManager.read(_i2cAddress, _inBuffer, 12, _outBuffer, 1, &_rb);
+        _nextState = 3;
+        delayUntil(currentMicros + 5000); // Allow 5ms to get data
+        _nextState = STATE_DECODERESULTS;
+        break;
+      case STATE_DECODERESULTS:
+        // If I2C write still busy, return.
+        status = _rb.status;
+        if (status == I2C_STATUS_PENDING) return; // try again next time
+        if (status == I2C_STATUS_OK) {
+          if (!(_inBuffer[0] & 1)) return; // device still busy
+          uint8_t deviceRangeStatus = ((_inBuffer[0] & 0x78) >> 3);
+          if (deviceRangeStatus == 0x0b) {
+            // Range status OK, so use data
+            _ambient = makeuint16(_inBuffer[7], _inBuffer[6]);
+            _signal = makeuint16(_inBuffer[9], _inBuffer[8]);
+            _distance = makeuint16(_inBuffer[11], _inBuffer[10]);
+            if (_distance <= _onThreshold) 
+              _value = true;
+            else if (_distance > _offThreshold) 
+              _value = false;
+          }
+        }
+        // Completed. Restart scan on next loop entry.
+        _nextState = STATE_INITIATESCAN;
+        break;
+      default:
+        break;
+    }
+  }
+
+  // For analogue read, first pin returns distance, second pin is signal strength, and third is ambient level.
+  int _readAnalogue(VPIN vpin) override {
+    int pin = vpin - _firstVpin;
+    switch (pin) {
+      case 0:
+        return _distance;
+      case 1:
+        return _signal;
+      case 2:
+        return _ambient;
+      default:
+        return -1;
+    }
+  }
+
+  // For digital read, return zero for all but first pin.
+  int _read(VPIN vpin) override {
+    if (vpin == _firstVpin)
+      return _value;
+    else
+      return 0;
+  }
+
+  void _display() override {
+    DIAG(F("VL53L0X I2C:x%x Configured on Vpins:%d-%d On:%dmm Off:%dmm %S"),
+      _i2cAddress, _firstVpin, _firstVpin+_nPins-1, _onThreshold, _offThreshold,
+      (_deviceState==DEVSTATE_FAILED) ? F("OFFLINE") : F(""));
+  }
+  
+
+private:
+  inline uint16_t makeuint16(byte lsb, byte msb) {
+    return (((uint16_t)msb) << 8) | lsb;
+  }
+  uint8_t write_reg(uint8_t reg, uint8_t data) {
+    // write byte to register
+    uint8_t outBuffer[2];
+    outBuffer[0] = reg;
+    outBuffer[1] = data;
+    return I2CManager.write(_i2cAddress, outBuffer, 2);
+  }
+  uint8_t read_reg(uint8_t reg) {
+    // read byte from register and return value
+    I2CManager.read(_i2cAddress, _inBuffer, 1, &reg, 1);
+    return _inBuffer[0];
+  }
+};
+
+#endif // IO_VL53L0X_h

LCDDisplay.cpp

@@ -1,6 +1,6 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
- *  
+ *  © 2021, Chris Harlow, Neil McKechnie. All rights reserved.
+ *
  *  This file is part of CommandStation-EX
  *
  *  This is free software: you can redistribute it and/or modify
@@ -17,63 +17,151 @@
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-// CAUTION: the device dependent parts of this class are created in the .ini using LCD_Implementation.h
+// CAUTION: the device dependent parts of this class are created in the .ini
+// using LCD_Implementation.h
+
+/* The strategy for drawing the screen is as follows.
+ *  1) There are up to eight rows of text to be displayed.
+ *  2) Blank rows of text are ignored.
+ *  3) If there are more non-blank rows than screen lines,
+ *     then all of the rows are displayed, with the rest of the
+ *     screen being blank.
+ *  4) If there are fewer non-blank rows than screen lines,
+ *     then a scrolling strategy is adopted so that, on each screen
+ *     refresh, a different subset of the rows is presented.
+ *  5) On each entry into loop2(), a single operation is sent to the 
+ *     screen; this may be a position command or a character for
+ *     display.  This spreads the onerous work of updating the screen
+ *     and ensures that other loop() functions in the application are
+ *     not held up significantly.  The exception to this is when 
+ *     the loop2() function is called with force=true, where 
+ *     a screen update is executed to completion.  This is normally
+ *     only done during start-up.
+ *  The scroll mode is selected by defining SCROLLMODE as 0, 1 or 2
+ *  in the config.h.
+ *  #define SCROLLMODE 0 is scroll continuous (fill screen if poss),
+ *  #define SCROLLMODE 1 is by page (alternate between pages),
+ *  #define SCROLLMODE 2 is by row (move up 1 row at a time).
+
+ */
+
 #include "LCDDisplay.h"
 
- void LCDDisplay::clear() {
-      clearNative();
-      for (byte row=0;row<MAX_LCD_ROWS; row++)  rowBuffer[row][0]='\0';
-      topRow=-1; // loop2 will fill from row 0
- }
+void LCDDisplay::clear() {
+  clearNative();
+  for (byte row = 0; row < MAX_LCD_ROWS; row++) rowBuffer[row][0] = '\0';
+  topRow = -1;  // loop2 will fill from row 0
+}
 
- void LCDDisplay::setRow(byte line) {
-      hotRow=line;
-      hotCol=0;
- }
+void LCDDisplay::setRow(byte line) {
+  hotRow = line;
+  hotCol = 0;
+}
 
 size_t LCDDisplay::write(uint8_t b) {
-     if (hotRow>=MAX_LCD_ROWS || hotCol>=MAX_LCD_COLS) return -1;
-     rowBuffer[hotRow][hotCol]=b;
-     hotCol++;
-     rowBuffer[hotRow][hotCol]=0;
-     return 1;
- }
- 
- void LCDDisplay::loop() {
-    if (!lcdDisplay) return;
-    lcdDisplay->loop2(false);
- }
- 
- LCDDisplay*  LCDDisplay::loop2(bool force) { 
-    if ((!force) && (millis() - lastScrollTime)< LCD_SCROLL_TIME) return NULL;
-    lastScrollTime=millis();
-    clearNative();
-    int rowFirst=nextFilledRow();
-    if (rowFirst<0)return NULL; // No filled rows
-    setRowNative(0);
-    writeNative(rowBuffer[rowFirst]);
-    for (int slot=1;slot<lcdRows;slot++) {
-      int rowNext=nextFilledRow();
-      if (rowNext==rowFirst){
-         // we have wrapped around and not filled the screen 
-         topRow=-1; // start again at first row next time.  
-         break; 
+  if (hotRow >= MAX_LCD_ROWS || hotCol >= MAX_LCD_COLS) return -1;
+  rowBuffer[hotRow][hotCol] = b;
+  hotCol++;
+  rowBuffer[hotRow][hotCol] = 0;
+  return 1;
+}
+
+void LCDDisplay::loop() {
+  if (!lcdDisplay) return;
+  lcdDisplay->loop2(false);
+}
+
+LCDDisplay *LCDDisplay::loop2(bool force) {
+  if (!lcdDisplay) return NULL;
+
+  // If output device is busy, don't do anything on this loop
+  //  This avoids blocking while waiting for the device to complete.
+  if (isBusy()) return NULL;  
+
+  unsigned long currentMillis = millis();
+
+  if (!force) {
+    // See if we're in the time between updates
+    if ((currentMillis - lastScrollTime) < LCD_SCROLL_TIME)
+      return NULL;
+  } else {
+    // force full screen update from the beginning.
+    rowFirst = -1;
+    rowNext = 0;
+    bufferPointer = 0;
+    done = false;
+    slot = 0;
+  }
+
+  do {
+    if (bufferPointer == 0) {
+      // Find a line of data to write to the screen.
+      if (rowFirst < 0) rowFirst = rowNext;
+      skipBlankRows();
+      if (!done) {
+        // Non-blank line found, so copy it.
+        for (uint8_t i = 0; i < sizeof(buffer); i++)
+          buffer[i] = rowBuffer[rowNext][i];
+      } else
+        buffer[0] = '\0';  // Empty line
+      setRowNative(slot);  // Set position for display
+      charIndex = 0;
+      bufferPointer = &buffer[0];
+
+    } else {
+
+      // Write next character, or a space to erase current position.
+      char ch = *bufferPointer;
+      if (ch) {
+        writeNative(ch);
+        bufferPointer++;
+      } else
+        writeNative(' ');
+
+      if (++charIndex >= MAX_LCD_COLS) {
+        // Screen slot completed, move to next slot on screen
+        slot++;
+        bufferPointer = 0;
+        if (!done) {
+          moveToNextRow();
+          skipBlankRows();
+        }
       }
-      setRowNative(slot);
-      writeNative(rowBuffer[rowNext]);
-    } 
-    displayNative();   
-    return NULL; 
- }
 
- int LCDDisplay::nextFilledRow() {
-      for (int rx=1;rx<=MAX_LCD_ROWS;rx++) {
-          topRow++;
-          topRow %= MAX_LCD_ROWS;
-          if (rowBuffer[topRow][0]) return topRow; 
-          }
-      return -1; // No slots filled
- }
+      if (slot >= lcdRows) {
+        // Last slot finished, reset ready for next screen update.
+#if SCROLLMODE==2
+        if (!done) {
+          // On next refresh, restart one row on from previous start.
+          rowNext = rowFirst;
+          moveToNextRow();
+          skipBlankRows();
+        }
+#endif
+        done = false;
+        slot = 0;
+        rowFirst = -1;
+        lastScrollTime = currentMillis;
+        return NULL;
+      }
+    }
+  } while (force);
 
-  
-   
+  return NULL;
+}
+
+void LCDDisplay::moveToNextRow() {
+  rowNext = (rowNext + 1) % MAX_LCD_ROWS;
+#if SCROLLMODE == 1
+  // Finished if we've looped back to row 0
+  if (rowNext == 0) done = true;
+#else
+  // Finished if we're back to the first one shown
+  if (rowNext == rowFirst) done = true;
+#endif
+}
+
+void LCDDisplay::skipBlankRows() {
+  while (!done && rowBuffer[rowNext][0] == 0)
+    moveToNextRow();
+}

LCDDisplay.h

@@ -1,6 +1,6 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
- *  
+ *  © 2021, Chris Harlow, Neil McKechnie. All rights reserved.
+ *
  *  This file is part of CommandStation-EX
  *
  *  This is free software: you can redistribute it and/or modify
@@ -19,45 +19,63 @@
 #ifndef LCDDisplay_h
 #define LCDDisplay_h
 #include <Arduino.h>
+#include "defines.h"
+#include "DisplayInterface.h"
+
+// Allow maximum message length to be overridden from config.h
+#if !defined(MAX_MSG_SIZE) 
+#define MAX_MSG_SIZE 20
+#endif
+
+// Set default scroll mode (overridable in config.h)
+#if !defined(SCROLLMODE) 
+#define SCROLLMODE 1
+#endif
 
 // This class is created in LCDisplay_Implementation.h
 
-class LCDDisplay : public Print {
+class LCDDisplay : public DisplayInterface {
+ public:
+  LCDDisplay() {};
+  static const int MAX_LCD_ROWS = 8;
+  static const int MAX_LCD_COLS = MAX_MSG_SIZE;
+  static const long LCD_SCROLL_TIME = 3000;  // 3 seconds
 
-  public:
-    static const int MAX_LCD_ROWS=8;
-    static const int MAX_LCD_COLS=16;
-    static const long LCD_SCROLL_TIME=3000; // 3 seconds  
-    
-    static LCDDisplay* lcdDisplay; 
-    LCDDisplay();
-    void interfake(int p1, int p2, int p3);    
+  // Internally handled functions
+  static void loop();
+  LCDDisplay* loop2(bool force) override;
+  void setRow(byte line) override;
+  void clear() override;
 
-    // Internally handled functions
-    static void loop();
-    LCDDisplay*  loop2(bool force);
-    void setRow(byte line); 
-    void clear();
-   
-    virtual size_t write(uint8_t b);
-    using Print::write;
-    
-  private:
-    int nextFilledRow();
-  
-   // Relay functions to the live driver
-    void clearNative();
-    void displayNative();
-    void setRowNative(byte line); 
-    void writeNative(char * b);
-  
-   unsigned long lastScrollTime=0;
-   int hotRow=0;
-   int hotCol=0; 
-   int topRow=0;
-   int lcdRows;
-   void renderRow(byte row);
-   char rowBuffer[MAX_LCD_ROWS][MAX_LCD_COLS+1];     
+  size_t write(uint8_t b) override;
+
+protected:
+  uint8_t lcdRows;
+  uint8_t lcdCols;
+
+ private:
+  void moveToNextRow();
+  void skipBlankRows();
+
+  // Relay functions to the live driver in the subclass
+  virtual void clearNative() = 0;
+  virtual void setRowNative(byte line) = 0;
+  virtual size_t writeNative(uint8_t b) = 0;
+  virtual bool isBusy() = 0;
+
+  unsigned long lastScrollTime = 0;
+  int8_t hotRow = 0;
+  int8_t hotCol = 0;
+  int8_t topRow = 0;
+  int8_t slot = 0;
+  int8_t rowFirst = -1;
+  int8_t rowNext = 0;
+  int8_t charIndex = 0;
+  char buffer[MAX_LCD_COLS + 1];
+  char* bufferPointer = 0;
+  bool done = false;
+
+  char rowBuffer[MAX_LCD_ROWS][MAX_LCD_COLS + 1];
 };
 
 #endif

LCD_Implementation.h

@@ -1,5 +1,5 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2021, Chris Harlow, Neil McKechnie. All rights reserved.
  *  
  *  This file is part of CommandStation-EX
  *
@@ -22,34 +22,32 @@
 //
 // It will create a driver implemntation and a shim class implementation.
 // This means that other classes can reference the shim without knowing
-// which libraray is involved.
+// which library is involved.
 ////////////////////////////////////////////////////////////////////////////////////
 
-#include "config.h"
-#include <Wire.h>
+#ifndef LCD_Implementation_h
+#define LCD_Implementation_h
 #include "LCDDisplay.h"
+#include "SSD1306Ascii.h"
+#include "LiquidCrystal_I2C.h"
   
-LCDDisplay * LCDDisplay::lcdDisplay=0;
 
 // Implement the LCDDisplay shim class as a singleton.
-// Notice that the LCDDisplay class declaration (LCDDisplay.h) is independent of the library
-// but the implementation is compiled here with dependencies on LCDDriver which is 
-// specific to the library in use.
-// Thats the workaround to the drivers not all implementing a common interface. 
- 
-#if defined(OLED_DRIVER) 
-  #include "LCD_OLED.h"
-  #define CONDITIONAL_LCD_START for (LCDDisplay * dummy=new LCDDisplay();dummy!=NULL; dummy=dummy->loop2(true)) 
+// The DisplayInterface class implements a displayy handler with no code (null device);
+// The LCDDisplay class sub-classes DisplayInterface to provide the common display code;
+// Then LCDDisplay class is subclassed to the specific device type classes:
+//    SSD1306AsciiWire for I2C OLED driver with SSD1306 or SH1106 controllers;
+//    LiquidCrystal_I2C for I2C LCD driver for HD44780 with PCF8574 'backpack'.
+
+#if defined(OLED_DRIVER)
+  #define CONDITIONAL_LCD_START for (DisplayInterface * dummy=new SSD1306AsciiWire(OLED_DRIVER);dummy!=NULL; dummy=dummy->loop2(true))
   
+#elif defined(LCD_DRIVER)
+  #define CONDITIONAL_LCD_START for (DisplayInterface * dummy=new LiquidCrystal_I2C(LCD_DRIVER);dummy!=NULL; dummy=dummy->loop2(true))
 
-#elif defined(LCD_DRIVER)  
-  #include "LCD_LCD.h"      
-  #define CONDITIONAL_LCD_START for (LCDDisplay * dummy=new LCDDisplay();dummy!=NULL; dummy=dummy->loop2(true))  
-
-#else 
-  #include "LCD_NONE.h"
-  #define CONDITIONAL_LCD_START if (false) /* NO LCD CONFIG */      
+#else
+  // Create null display handler just in case someone calls lcdDisplay->something without checking if lcdDisplay is NULL!
+  #define CONDITIONAL_LCD_START { new DisplayInterface(); }
 #endif
- 
 
-  
+#endif // LCD_Implementation_h

LCD_LCD.h

@@ -1,37 +0,0 @@
-/*
- *  © 2020, Chris Harlow. All rights reserved.
- *  
- *  This file is part of CommandStation-EX
- *
- *  This is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation, either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  It is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
- */
-  #include <LiquidCrystal_I2C.h> 
-  LiquidCrystal_I2C LCDDriver(LCD_DRIVER);  // set the LCD address, cols, rows 
-  // DEVICE SPECIFIC LCDDisplay Implementation for LCD_DRIVER
-  LCDDisplay::LCDDisplay() { 
-    lcdDisplay=this;
-    LCDDriver.init();
-    LCDDriver.backlight();
-    interfake(LCD_DRIVER);
-    clear();
-  }
-  void LCDDisplay::interfake(int p1, int p2, int p3) {(void)p1; (void)p2; lcdRows=p3; }   
-  void LCDDisplay::clearNative() {LCDDriver.clear();}
-  void LCDDisplay::setRowNative(byte row) { 
-    LCDDriver.setCursor(0, row);
-    LCDDriver.print(F("                "));
-    LCDDriver.setCursor(0, row);
-    }
-  void LCDDisplay::writeNative(char * b){ LCDDriver.print(b); }    
-  void LCDDisplay::displayNative() { LCDDriver.display(); }

LCD_OLED.h

@@ -1,57 +0,0 @@
-/*
- *  © 2020, Chris Harlow. All rights reserved.
- *  
- *  This file is part of CommandStation-EX
- *
- *  This is free software: you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation, either version 3 of the License, or
- *  (at your option) any later version.
- *
- *  It is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
- */
-
-// OLED Implementation of LCDDisplay class 
-// Note: this file is optionally included by LCD_Implenentation.h
-// It is NOT a .cpp file to prevent it being compiled and demanding libraraies even when not needed.
-  
-#include <Adafruit_SSD1306.h>
-Adafruit_SSD1306 LCDDriver(OLED_DRIVER);
-  
-// DEVICE SPECIFIC LCDDisplay Implementation for OLED
-
-LCDDisplay::LCDDisplay() {
-    if(LCDDriver.begin(SSD1306_SWITCHCAPVCC, 0x3C) || LCDDriver.begin(SSD1306_SWITCHCAPVCC, 0x3D)) {
-      DIAG(F("\nOLED display found")); 
-      delay(2000); // painful Adafruit splash pants! 
-      lcdDisplay=this;
-      LCDDriver.setTextSize(1);             // Normal 1:1 pixel scale
-      LCDDriver.setTextColor(SSD1306_WHITE);            // Draw white text
-      interfake(OLED_DRIVER,0);
-      clear();
-      return;  
-      }
-    DIAG(F("\nOLED display not found\n"));
-    }
-
-  void LCDDisplay::interfake(int p1, int p2, int p3) {(void)p1; lcdRows=p2/8; (void)p3;}   
-
-  void LCDDisplay::clearNative() {LCDDriver.clearDisplay();}
-
-  void LCDDisplay::setRowNative(byte row) {
-    // Positions text write to start of row 1..n and clears previous text 
-    int y=8*row;
-    LCDDriver.fillRect(0, y, LCDDriver.width(),   8, SSD1306_BLACK);
-    LCDDriver.setCursor(0, y); 
-    }
-  
-  void LCDDisplay::writeNative(char * b){ LCDDriver.print(b); }    
-  
-  void LCDDisplay::displayNative() { LCDDriver.display(); }  
-  

LCN.cpp

@@ -0,0 +1,72 @@
+/*
+ *  © 2021, Chris Harlow. All rights reserved.
+ *  
+ *  This file is part of DCC-EX CommandStation-EX 
+ *  
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "LCN.h"
+#include "DIAG.h"
+#include "Turnouts.h"
+#include "Sensors.h"
+
+int  LCN::id = 0;
+Stream * LCN::stream=NULL;
+bool LCN::firstLoop=true;
+
+void LCN::init(Stream & lcnstream) {
+  stream=&lcnstream; 
+  DIAG(F("LCN connection setup")); 
+}
+
+
+// Inbound LCN traffic is postfix notation...   nnnX  where nnn is an id, X is the opcode
+void LCN::loop() {
+  if (!stream) return;
+  if (firstLoop) {
+    firstLoop=false;
+    stream->println('X');
+    return; 
+  }
+  
+  while (stream->available()) {
+    int ch = stream->read();
+    if (ch >= 0 && ch <= '9') {  // accumulate id value
+      id = 10 * id + ch - '0';
+    }
+    else if (ch == 't' || ch == 'T') { // Turnout opcodes
+      if (Diag::LCN) DIAG(F("LCN IN %d%c"),id,(char)ch);
+      if (!Turnout::exists(id)) LCNTurnout::create(id);
+      Turnout::setClosedStateOnly(id,ch=='t');
+      Turnout::turnoutlistHash++; // signals ED update of turnout data
+      id = 0;
+    }
+    else if (ch == 'S' || ch == 's') {
+      if (Diag::LCN) DIAG(F("LCN IN %d%c"),id,(char)ch);
+      Sensor * ss = Sensor::get(id);
+      if (!ss) ss = Sensor::create(id, VPIN_NONE, 0); // impossible pin
+      ss->setState(ch == 'S');
+      id = 0;
+    }
+    else  id = 0; // ignore any other garbage from LCN
+  }
+}
+
+void LCN::send(char opcode, int id, bool state) {
+   if (stream) {
+      StringFormatter::send(stream,F("%c/%d/%d"), opcode, id , state);
+      if (Diag::LCN) DIAG(F("LCN OUT %c/%d/%d"), opcode, id , state);
+   }
+}

LCN.h

@@ -1,5 +1,5 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  (c) 2021 Fred Decker.  All rights reserved.
  *  
  *  This file is part of CommandStation-EX
  *
@@ -16,12 +16,19 @@
  *  You should have received a copy of the GNU General Public License
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
+#ifndef LCN_h
+#define LCN_h
+#include <Arduino.h>
 
-// dummy LCD shim to keep linker happy
-  LCDDisplay::LCDDisplay() {} 
-  void LCDDisplay::interfake(int p1, int p2, int p3) {(void)p1; (void)p2; (void)p3;}   
-  void LCDDisplay::setRowNative(byte row) { (void)row;} 
-  void LCDDisplay::clearNative() {}
-  void LCDDisplay::writeNative(char * b){ (void)b;} //  
-  void LCDDisplay::displayNative(){}
-  
+class LCN {
+  public: 
+    static void init(Stream & lcnstream);
+    static void loop();
+    static void send(char opcode, int id, bool state);
+  private :
+    static bool firstLoop; 
+    static Stream * stream; 
+    static int id;
+};
+
+#endif

LiquidCrystal_I2C.cpp

@@ -0,0 +1,219 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  Based on the work by DFRobot, Frank de Brabander and Marco Schwartz.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation-EX.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <Arduino.h>
+#include "LiquidCrystal_I2C.h"
+#include "DIAG.h"
+
+// When the display powers up, it is configured as follows:
+//
+// 1. Display clear
+// 2. Function set:
+//    DL = 1; 8-bit interface data
+//    N = 0; 1-line display
+//    F = 0; 5x8 dot character font
+// 3. Display on/off control:
+//    D = 0; Display off
+//    C = 0; Cursor off
+//    B = 0; Blinking off
+// 4. Entry mode set:
+//    I/D = 1; Increment by 1
+//    S = 0; No shift
+//
+// Note, however, that resetting the Arduino doesn't reset the LCD, so we
+// can't assume that its in that state when a sketch starts (and the
+// LiquidCrystal constructor is called).
+
+LiquidCrystal_I2C::LiquidCrystal_I2C(uint8_t lcd_Addr, uint8_t lcd_cols,
+                                     uint8_t lcd_rows) {
+  _Addr = lcd_Addr;
+  lcdRows = lcd_rows;
+  lcdCols = lcd_cols;
+
+  _backlightval = 0;
+
+  I2CManager.begin();
+  I2CManager.setClock(100000L);    // PCF8574 is spec'd to 100kHz.
+
+  if (I2CManager.exists(lcd_Addr)) {
+    DIAG(F("%dx%d LCD configured on I2C:x%x"), (int)lcd_cols, (int)lcd_rows, (int)lcd_Addr);
+    _displayfunction = LCD_4BITMODE | LCD_1LINE | LCD_5x8DOTS;
+    begin();
+    backlight();
+    lcdDisplay = this;
+  }
+}
+
+void LiquidCrystal_I2C::begin() {
+  if (lcdRows > 1) {
+    _displayfunction |= LCD_2LINE;
+  }
+
+  // according to datasheet, we need at least 40ms after power rises above 2.7V
+  // before sending commands. Arduino can turn on way before 4.5V so we'll allow
+  // 100 milliseconds after pulling both RS and R/W and backlight pin low
+  expanderWrite(
+      _backlightval);  // reset expander and turn backlight off (Bit 8 =1)
+  delay(100);
+
+  // put the LCD into 4 bit mode
+  // this is according to the hitachi HD44780 datasheet
+  // figure 24, pg 46
+
+  // we start in 8bit mode, try to set 4 bit mode
+  write4bits(0x03);
+  delayMicroseconds(4500);  // wait min 4.1ms
+
+  // second try
+  write4bits(0x03);
+  delayMicroseconds(4500);  // wait min 4.1ms
+
+  // third go!
+  write4bits(0x03);
+  delayMicroseconds(150);
+
+  // finally, set to 4-bit interface
+  write4bits(0x02);
+
+  // set # lines, font size, etc.
+  command(LCD_FUNCTIONSET | _displayfunction);
+
+  // turn the display on with no cursor or blinking default
+  _displaycontrol = LCD_DISPLAYON | LCD_CURSOROFF | LCD_BLINKOFF;
+  display();
+
+  // clear it off
+  clear();
+
+  // Initialize to default text direction (for roman languages)
+  _displaymode = LCD_ENTRYLEFT | LCD_ENTRYSHIFTDECREMENT;
+
+  // set the entry mode
+  command(LCD_ENTRYMODESET | _displaymode);
+
+  setRowNative(0);
+}
+
+/********** high level commands, for the user! */
+void LiquidCrystal_I2C::clearNative() {
+  command(LCD_CLEARDISPLAY);  // clear display, set cursor position to zero
+  delayMicroseconds(2000);    // this command takes 1.52ms
+}
+
+void LiquidCrystal_I2C::setRowNative(byte row) {
+  int row_offsets[] = {0x00, 0x40, 0x14, 0x54};
+  if (row >= lcdRows) {
+    row = lcdRows - 1;  // we count rows starting w/0
+  }
+  command(LCD_SETDDRAMADDR | (row_offsets[row]));
+}
+
+void LiquidCrystal_I2C::display() {
+  _displaycontrol |= LCD_DISPLAYON;
+  command(LCD_DISPLAYCONTROL | _displaycontrol);
+}
+
+// Turn the (optional) backlight off/on
+void LiquidCrystal_I2C::noBacklight(void) {
+  _backlightval &= ~LCD_BACKLIGHT;
+  expanderWrite(0);
+}
+
+void LiquidCrystal_I2C::backlight(void) {
+  _backlightval = LCD_BACKLIGHT;
+  expanderWrite(0);
+}
+
+size_t LiquidCrystal_I2C::writeNative(uint8_t value) {
+  send(value, Rs);
+  return 1;
+}
+
+/*********** mid level commands, for sending data/cmds */
+
+inline void LiquidCrystal_I2C::command(uint8_t value) { 
+  send(value, 0); 
+}
+
+/************ low level data pushing commands **********/
+
+/* According to the NXP Datasheet for the PCF8574 section 8.2:
+ *   "The master (microcontroller) sends the START condition and slave address
+ *    setting the last bit of the address byte to logic 0 for the write mode.
+ *    The PCF8574/74A acknowledges and the master then sends the data byte for
+ *    P7 to P0 to the port register. As the clock line goes HIGH, the 8-bit
+ *    data is presented on the port lines after it has been acknowledged by the
+ *    PCF8574/74A. [...] The master can then send a STOP or ReSTART condition
+ *    or continue sending data. The number of data bytes that can be sent 
+ *    successively is not limited and the previous data is overwritten every
+ *    time a data byte has been sent and acknowledged."
+ * 
+ * This driver takes advantage of this by sending multiple data bytes in succession
+ * within a single I2C transmission.  With a fast clock rate of 400kHz, the time
+ * between successive updates of the PCF8574 outputs will be at least 2.5us.  With
+ * the default clock rate of 100kHz the time between updates will be at least 10us.
+ * 
+ * The LCD controller HD44780, according to its datasheet, needs nominally 37us
+ * (up to 50us) to execute a command (i.e. write to gdram, reposition, etc.). Each
+ * command is sent in a separate I2C transmission here.  The time taken to end a 
+ * transmission and start another one is a stop bit, a start bit, 8 address bits,
+ * an ack, 8 data bits and another ack; this is at least 20 bits, i.e. >50us
+ * at 400kHz and >200us at 100kHz. Therefore, we don't need additional delay.
+ * 
+ * Similarly, the Enable must be set/reset for at least 450ns.  This is 
+ * well within the I2C clock cycle time of 2.5us at 400kHz.  Data is clocked in
+ * to the HD44780 on the trailing edge of the Enable pin, so we set the Enable
+ * as we present the data, then in the next byte we reset Enable without changing
+ * the data.
+ */
+
+// write either command or data (8 bits) to the HD44780 LCD controller as
+//  a single I2C transmission. 
+void LiquidCrystal_I2C::send(uint8_t value, uint8_t mode) {
+  mode |= _backlightval;
+  uint8_t highnib = (((value >> 4) & 0x0f) << BACKPACK_DATA_BITS) | mode;
+  uint8_t lownib = ((value & 0x0f) << BACKPACK_DATA_BITS) | mode;
+  // Send both nibbles
+  uint8_t len = 0;
+  outputBuffer[len++] = highnib|En;
+  outputBuffer[len++] = highnib;
+  outputBuffer[len++] = lownib|En;
+  outputBuffer[len++] = lownib;
+  I2CManager.write(_Addr, outputBuffer, len);  // Write command synchronously
+}
+
+// write 4 data bits to the HD44780 LCD controller.
+void LiquidCrystal_I2C::write4bits(uint8_t value) {
+  uint8_t _data = ((value & 0x0f) << BACKPACK_DATA_BITS) | _backlightval;
+  // Enable must be set/reset for at least 450ns.  This is well within the
+  // I2C clock cycle time of 2.5us at 400kHz. Data is clocked in to the
+  // HD44780 on the trailing edge of the Enable pin.
+  uint8_t len = 0;
+  outputBuffer[len++] = _data|En;
+  outputBuffer[len++] = _data;
+  I2CManager.write(_Addr, outputBuffer, len);  // Write command synchronously
+}
+
+// write a byte to the PCF8574 I2C interface.  We don't need to set
+// the enable pin for this.
+void LiquidCrystal_I2C::expanderWrite(uint8_t value) {
+  outputBuffer[0] = value | _backlightval;
+  I2CManager.write(_Addr, outputBuffer, 1);  // Write command synchronously
+}

LiquidCrystal_I2C.h

@@ -0,0 +1,94 @@
+/*
+ *  © 2021, Neil McKechnie. All rights reserved.
+ *  Based on the work by DFRobot, Frank de Brabander and Marco Schwartz.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef LiquidCrystal_I2C_h
+#define LiquidCrystal_I2C_h
+
+#include <Arduino.h>
+#include "LCDDisplay.h"
+#include "I2CManager.h"
+
+// commands
+#define LCD_CLEARDISPLAY 0x01
+#define LCD_ENTRYMODESET 0x04
+#define LCD_DISPLAYCONTROL 0x08
+#define LCD_FUNCTIONSET 0x20
+#define LCD_SETCGRAMADDR 0x40
+#define LCD_SETDDRAMADDR 0x80
+
+// flags for display entry mode
+#define LCD_ENTRYRIGHT 0x00
+#define LCD_ENTRYLEFT 0x02
+#define LCD_ENTRYSHIFTINCREMENT 0x01
+#define LCD_ENTRYSHIFTDECREMENT 0x00
+
+// flags for display on/off control
+#define LCD_DISPLAYON 0x04
+#define LCD_CURSOROFF 0x00
+#define LCD_BLINKOFF 0x00
+
+// flags for function set
+#define LCD_4BITMODE 0x00
+#define LCD_2LINE 0x08
+#define LCD_1LINE 0x00
+#define LCD_5x8DOTS 0x00
+
+// Bit mapping onto PCF8574 port
+#define BACKPACK_Rs_BIT 0
+#define BACKPACK_Rw_BIT 1
+#define BACKPACK_En_BIT 2
+#define BACKPACK_BACKLIGHT_BIT 3
+#define BACKPACK_DATA_BITS 4 // Bits 4-7
+// Equivalent mask bits
+#define LCD_BACKLIGHT (1 << BACKPACK_BACKLIGHT_BIT)  // Backlight enable
+#define En (1 << BACKPACK_En_BIT)  // Enable bit
+#define Rw (1 << BACKPACK_Rw_BIT)  // Read/Write bit
+#define Rs (1 << BACKPACK_Rs_BIT)  // Register select bit
+
+class LiquidCrystal_I2C : public LCDDisplay {
+public:
+  LiquidCrystal_I2C(uint8_t lcd_Addr,uint8_t lcd_cols,uint8_t lcd_rows);
+  void begin();
+  void clearNative() override;
+  void setRowNative(byte line) override;
+  size_t writeNative(uint8_t c) override;
+  
+  void display();
+  void noBacklight();
+  void backlight();
+  
+  void command(uint8_t);
+
+private:
+  void send(uint8_t, uint8_t);
+  void write4bits(uint8_t);
+  void expanderWrite(uint8_t);
+  uint8_t _Addr;
+  uint8_t _displayfunction;
+  uint8_t _displaycontrol;
+  uint8_t _displaymode;
+  uint8_t _backlightval;
+
+  uint8_t outputBuffer[4];
+  // I/O is synchronous, so if this is called we're not busy!
+  bool isBusy() override { return false; } 
+};
+
+#endif

MemStream.cpp

@@ -1,98 +0,0 @@
-/*
-
- (c) 2015 Ingo Fischer
- buffer serial device
- based on Arduino SoftwareSerial
-
- Constructor warning messages fixed by Chris Harlow.
-
-This library is free software; you can redistribute it and/or
-modify it under the terms of the GNU Lesser General Public
-License as published by the Free Software Foundation; either
-version 2.1 of the License, or (at your option) any later version.
-
-This library is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-Lesser General Public License for more details.
-
-You should have received a copy of the GNU Lesser General Public
-License along with this library; if not, write to the Free Software
-Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
-
-*/
-
-#include "MemStream.h"
-
-MemStream::MemStream(uint8_t *buffer, const uint16_t len, uint16_t content_len, bool allowWrite)
-:_buffer(buffer),_len(len), _buffer_overflow(false),  _pos_read(0), _allowWrite(allowWrite)
-{
-  if (content_len==0) memset(_buffer, 0, _len);
-  _pos_write=(content_len>len)? len: content_len;
-}
-
-size_t MemStream::write(uint8_t byte) {
-  if (! _allowWrite) return -1;
-  if (_pos_write >= _len) {
-    _buffer_overflow = true;
-    return 0;
-  }
-  _buffer[_pos_write] = byte;
-  ++_pos_write;
-  return 1;
-}
-
-void MemStream::flush() {
-  memset(_buffer, 0, _len);
-  _pos_write = 0;
-  _pos_read = 0;
-}
-
-int MemStream::read() {
-  if (_pos_read >= _len) {
-    _buffer_overflow = true;
-    return -1;
-  }
-  if (_pos_read >= _pos_write) {
-    return -1;
-  }
-  return _buffer[_pos_read++];
-}
-
-int MemStream::peek() {
-  if (_pos_read >= _len) {
-    _buffer_overflow = true;
-    return -1;
-  }
-  if (_pos_read >= _pos_write) {
-    return -1;
-  }
-  return _buffer[_pos_read+1];
-}
-
-int MemStream::available() {
-  int ret=_pos_write-_pos_read;
-  if (ret<0) ret=0;
-  return ret;
-}
-
-void MemStream::setBufferContent(uint8_t *buffer, uint16_t content_len) {
-  memset(_buffer, 0, _len);
-  memcpy(_buffer, buffer, content_len);
-  _buffer_overflow=false;
-  _pos_write=content_len;
-  _pos_read=0;
-}
-
-void MemStream::setBufferContentFromProgmem(uint8_t *buffer, uint16_t content_len) {
-  memset(_buffer, 0, _len);
-  memcpy_P(_buffer, buffer, content_len);
-  _buffer_overflow=false;
-  _pos_write=content_len;
-  _pos_read=0;
-}
-
-void MemStream::setBufferContentPosition(uint16_t read_pos, uint16_t write_pos) {
-    _pos_write=write_pos;
-    _pos_read=read_pos;
-}

MemStream.h

@@ -1,78 +0,0 @@
-/*
-
-  (c) 2015 Ingo FIscher
-  buffer serial device
-  based on Arduino SoftwareSerial
-
-This library is free software; you can redistribute it and/or
-modify it under the terms of the GNU Lesser General Public
-License as published by the Free Software Foundation; either
-version 2.1 of the License, or (at your option) any later version.
-
-This library is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-Lesser General Public License for more details.
-
-You should have received a copy of the GNU Lesser General Public
-License along with this library; if not, write to the Free Software
-Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
-
-*/
-
-#ifndef MemStream_h
-#define MemStream_h
-
-#include <inttypes.h>
-#if defined(ARDUINO_ARCH_MEGAAVR)
-#include <Arduino.h>
-#else
-#include <Stream.h>
-#endif
-
-#include <avr/pgmspace.h>
-
-class MemStream : public Stream
-{
-private:
-  uint8_t *_buffer;
-  const uint16_t _len;
-  bool _buffer_overflow;
-  uint16_t _pos_read;
-  uint16_t _pos_write;
-  bool _allowWrite;
-
-public:
-  // public methods
-  MemStream(uint8_t *buffer, const uint16_t len, uint16_t content_len = 0, bool allowWrite = true);
-  ~MemStream() {}
-
-  operator const uint8_t *() const { return _buffer; }
-  operator const char *() const { return (const char *)_buffer; }
-
-  uint16_t current_length() const { return _pos_write; }
-
-  bool listen() { return true; }
-  void end() {}
-  bool isListening() { return true; }
-  bool overflow()
-  {
-    bool ret = _buffer_overflow;
-    _buffer_overflow = false;
-    return ret;
-  }
-  int peek();
-
-  virtual size_t write(uint8_t byte);
-  virtual int read();
-  virtual int available();
-  virtual void flush();
-
-  void setBufferContent(uint8_t *buffer, uint16_t content_len);
-  void setBufferContentFromProgmem(uint8_t *buffer, uint16_t content_len);
-  void setBufferContentPosition(uint16_t read_pos, uint16_t write_pos);
-
-  using Print::write;
-};
-
-#endif

MotorDriver.cpp

@@ -18,50 +18,88 @@
  */
 #include <Arduino.h>
 #include "MotorDriver.h"
-#include "AnalogReadFast.h"
+#include "DCCTimer.h"
 #include "DIAG.h"
-
-
-
-#if defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_ARCH_SAMC) || defined(ARDUINO_ARCH_MEGAAVR)
-    #define WritePin digitalWrite
-    #define ReadPin digitalRead
-#else
-    // use the DIO2 libraray for much faster pin access
-    #define GPIO2_PREFER_SPEED 1
-    #include <DIO2.h>  // use IDE menu Tools..Manage Libraries to locate and  install DIO2
-    #define WritePin digitalWrite2
-    #define ReadPin digitalRead2
+#if defined(ARDUINO_ARCH_ESP32)
+#include <driver/adc.h>
+#define pinToADC1Channel(X) (adc1_channel_t)(((X) > 35) ? (X)-36 : (X)-28)
 #endif
-    
+
+bool MotorDriver::usePWM=false;
+bool MotorDriver::commonFaultPin=false;
+       
 MotorDriver::MotorDriver(byte power_pin, byte signal_pin, byte signal_pin2, int8_t brake_pin,
                          byte current_pin, float sense_factor, unsigned int trip_milliamps, byte fault_pin) {
   powerPin=power_pin;
+  getFastPin(F("POWER"),powerPin,fastPowerPin);
+  pinMode(powerPin, OUTPUT);
+  
   signalPin=signal_pin;
+  getFastPin(F("SIG"),signalPin,fastSignalPin);
+  pinMode(signalPin, OUTPUT);
+  
   signalPin2=signal_pin2;
+  if (signalPin2!=UNUSED_PIN) {
+    dualSignal=true;
+    getFastPin(F("SIG2"),signalPin2,fastSignalPin2);
+    pinMode(signalPin2, OUTPUT);
+  }
+  else dualSignal=false; 
+  
   brakePin=brake_pin;
+  if (brake_pin!=UNUSED_PIN){
+    invertBrake=brake_pin < 0;
+    brakePin=invertBrake ? 0-brake_pin : brake_pin;
+    getFastPin(F("BRAKE"),brakePin,fastBrakePin);
+    pinMode(brakePin, OUTPUT);
+    setBrake(false);
+  }
+  else brakePin=UNUSED_PIN;
+  
   currentPin=current_pin;
-  senseFactor=sense_factor;
+  if (currentPin!=UNUSED_PIN) {
+#if defined(ARDUINO_ARCH_ESP32)
+    pinMode(currentPin, ANALOG);
+    adc1_config_width(ADC_WIDTH_BIT_12);
+    adc1_config_channel_atten(pinToADC1Channel(currentPin),ADC_ATTEN_DB_11);
+    senseOffset = adc1_get_raw(pinToADC1Channel(currentPin));
+#else
+    pinMode(currentPin, INPUT);
+    senseOffset=analogRead(currentPin); // value of sensor at zero current
+#endif
+  }
+
   faultPin=fault_pin;
+  if (faultPin != UNUSED_PIN) {
+    getFastPin(F("FAULT"),faultPin, 1 /*input*/, fastFaultPin);
+    pinMode(faultPin, INPUT);
+  }
+
+  senseFactor=sense_factor;
   tripMilliamps=trip_milliamps;
   rawCurrentTripValue=(int)(trip_milliamps / sense_factor);
-  pinMode(powerPin, OUTPUT);
-  pinMode(brakePin < 0 ? -brakePin : brakePin, OUTPUT);
-  setBrake(false);
-  pinMode(signalPin, OUTPUT);
-  if (signalPin2 != UNUSED_PIN) pinMode(signalPin2, OUTPUT);
-  pinMode(currentPin, INPUT);
-  if (faultPin != UNUSED_PIN) pinMode(faultPin, INPUT);
+  
+  if (currentPin==UNUSED_PIN) 
+    DIAG(F("MotorDriver ** WARNING ** No current or short detection"));  
+  else  
+    DIAG(F("MotorDriver currentPin=A%d, senseOffset=%d, rawCurentTripValue(relative to offset)=%d"),
+    currentPin-A0, senseOffset,rawCurrentTripValue);
 }
 
+bool MotorDriver::isPWMCapable() {
+    return (!dualSignal) && DCCTimer::isPWMPin(signalPin); 
+}
+
+
 void MotorDriver::setPower(bool on) {
-  if (brakePin == -4 && on) {
+  if (on) {
     // toggle brake before turning power on - resets overcurrent error
     // on the Pololu board if brake is wired to ^D2.
     setBrake(true);
     setBrake(false);
+    setHIGH(fastPowerPin);
   }
-  WritePin(powerPin, on ? HIGH : LOW);
+  else setLOW(fastPowerPin);
 }
 
 // setBrake applies brake if on == true. So to get
@@ -73,30 +111,68 @@ void MotorDriver::setPower(bool on) {
 // compensate for that.
 //
 void MotorDriver::setBrake(bool on) {
-    bool state = on;
-    byte pin = brakePin;
-    if (brakePin < 0) {
-      pin=-pin;
-      state=!state;
-    }
-    WritePin(pin, state ? HIGH : LOW);
-    //DIAG(F("BrakePin: %d is %d\n"), pin, ReadPin(pin));
+  if (brakePin == UNUSED_PIN) return;
+  if (on ^ invertBrake) setHIGH(fastBrakePin);
+  else setLOW(fastBrakePin);
 }
 
-void MotorDriver::setSignal( bool high) {
-  WritePin(signalPin, high ? HIGH : LOW);
-  if (signalPin2 != UNUSED_PIN) WritePin(signalPin2, high ? LOW : HIGH);
+void IRAM_ATTR MotorDriver::setSignal( bool high) {
+   if (usePWM) {
+    DCCTimer::setPWM(signalPin,high);
+   }
+   else {
+     if (high) {
+        setHIGH(fastSignalPin);
+        if (dualSignal) setLOW(fastSignalPin2);
+     }
+     else {
+        setLOW(fastSignalPin);
+        if (dualSignal) setHIGH(fastSignalPin2);
+     }
+   }
 }
 
+#if defined(ARDUINO_TEENSY32) || defined(ARDUINO_TEENSY35)|| defined(ARDUINO_TEENSY36)
+volatile unsigned int overflow_count=0;
+#endif
 
+bool MotorDriver::canMeasureCurrent() {
+  return currentPin!=UNUSED_PIN;
+}
+/*
+ * Return the current reading as pin reading 0 to 1023. If the fault
+ * pin is activated return a negative current to show active fault pin.
+ * As there is no -0, create a little and return -1 in that case.
+ * 
+ * senseOffset handles the case where a shield returns values above or below 
+ * a central value depending on direction.
+ */
 int MotorDriver::getCurrentRaw() {
-  if (faultPin != UNUSED_PIN && ReadPin(faultPin) == LOW && ReadPin(powerPin) == HIGH)
-      return (int)(32000/senseFactor);
-  
+  if (currentPin==UNUSED_PIN) return 0; 
+  int current;
+#if defined(ARDUINO_TEENSY40) || defined(ARDUINO_TEENSY41)
+  bool irq = disableInterrupts();
+  current = analogRead(currentPin)-senseOffset;
+  enableInterrupts(irq);
+#elif defined(ARDUINO_TEENSY32) || defined(ARDUINO_TEENSY35)|| defined(ARDUINO_TEENSY36)
+  unsigned char sreg_backup;
+  sreg_backup = SREG;   /* save interrupt enable/disable state */
+  cli();
+  current = analogRead(currentPin)-senseOffset;
+  overflow_count = 0;
+  SREG = sreg_backup;    /* restore interrupt state */
+#elif defined(ARDUINO_ARCH_ESP32)
+  current = adc1_get_raw(pinToADC1Channel(currentPin))-senseOffset;
+#else
+  current = analogRead(currentPin)-senseOffset;
+#endif
+  if (current<0) current=0-current;
+  if ((faultPin != UNUSED_PIN)  && isLOW(fastFaultPin) && isHIGH(fastPowerPin))
+      return (current == 0 ? -1 : -current);
+  return current;
   // IMPORTANT:  This function can be called in Interrupt() time within the 56uS timer
   //             The default analogRead takes ~100uS which is catastrphic
-  //             so analogReadFast is used here. (-2uS) 
-  return analogReadFast(currentPin);
+  //             so DCCTimer has set the sample time to be much faster.  
 }
 
 unsigned int MotorDriver::raw2mA( int raw) {
@@ -105,3 +181,16 @@ unsigned int MotorDriver::raw2mA( int raw) {
 int MotorDriver::mA2raw( unsigned int mA) {
   return (int)(mA / senseFactor);
 }
+
+void  MotorDriver::getFastPin(const FSH* type,int pin, bool input, FASTPIN & result) {
+    // DIAG(F("MotorDriver %S Pin=%d,"),type,pin);
+    (void) type; // avoid compiler warning if diag not used above.
+    PORTTYPE port = digitalPinToPort(pin);
+    if (input)
+      result.inout = portInputRegister(port);
+    else
+      result.inout = portOutputRegister(port);
+    result.maskHIGH = digitalPinToBitMask(pin);
+    result.maskLOW = ~result.maskHIGH;
+    // DIAG(F(" port=0x%x, inoutpin=0x%x, isinput=%d, mask=0x%x"),port, result.inout,input,result.maskHIGH);
+}

MotorDriver.h

@@ -18,30 +18,92 @@
  */
 #ifndef MotorDriver_h
 #define MotorDriver_h
+#include "defines.h"
+#include "FSH.h"
+
 // Virtualised Motor shield 1-track hardware Interface
 
 #ifndef UNUSED_PIN     // sync define with the one in MotorDrivers.h
 #define UNUSED_PIN 127 // inside int8_t
 #endif
 
+#if defined(__IMXRT1062__) || defined(ESP_FAMILY)
+typedef uint32_t PORTTYPE;
+struct FASTPIN {
+  volatile uint32_t *inout;
+  uint32_t maskHIGH;  
+  uint32_t maskLOW;  
+};
+#else
+typedef uint8_t PORTTYPE;
+struct FASTPIN {
+  volatile uint8_t *inout;
+  uint8_t maskHIGH;  
+  uint8_t maskLOW;  
+};
+#endif
+
+#define setHIGH(fastpin)  *fastpin.inout |= fastpin.maskHIGH
+#define setLOW(fastpin)   *fastpin.inout &= fastpin.maskLOW
+#define isHIGH(fastpin)   (*fastpin.inout & fastpin.maskHIGH)
+#define isLOW(fastpin)    (!isHIGH(fastpin))
+
 class MotorDriver {
   public:
-    MotorDriver(byte power_pin, byte signal_pin, byte signal_pin2, int8_t brake_pin, byte current_pin, float senseFactor, unsigned int tripMilliamps, byte faultPin);
+    MotorDriver(byte power_pin, byte signal_pin, byte signal_pin2, int8_t brake_pin, 
+                byte current_pin, float senseFactor, unsigned int tripMilliamps, byte faultPin);
     virtual void setPower( bool on);
-    virtual void setSignal( bool high);
+    void setSignal( bool high);/* {
+      if (usePWM) {
+	DCCTimer::setPWM(signalPin,high);
+      }
+      
+      if (high) {
+        setHIGH(fastSignalPin);
+        if (dualSignal) setLOW(fastSignalPin2);
+      }
+      else {
+        setLOW(fastSignalPin);
+        if (dualSignal) setHIGH(fastSignalPin2);
+      }
+      };*/
     virtual void setBrake( bool on);
     virtual int  getCurrentRaw();
     virtual unsigned int raw2mA( int raw);
     virtual int mA2raw( unsigned int mA);
     inline int getRawCurrentTripValue() {
-	return rawCurrentTripValue;
+	    return rawCurrentTripValue;
+    }
+    bool isPWMCapable();
+    bool canMeasureCurrent();
+    static bool usePWM;
+    static bool commonFaultPin; // This is a stupid motor shield which has only a common fault pin for both outputs
+    inline byte getFaultPin() {
+	return faultPin;
     }
-
   private:
-    byte powerPin, signalPin, signalPin2, currentPin, faultPin;
-    int8_t brakePin;       // negative means pin is inverted
+    void  getFastPin(const FSH* type,int pin, bool input, FASTPIN & result);
+    void  getFastPin(const FSH* type,int pin, FASTPIN & result) {
+	getFastPin(type, pin, 0, result);
+    }
+    byte powerPin, signalPin, signalPin2, currentPin, faultPin, brakePin;
+    FASTPIN fastPowerPin,fastSignalPin, fastSignalPin2, fastBrakePin,fastFaultPin;
+    bool dualSignal;       // true to use signalPin2
+    bool invertBrake;       // brake pin passed as negative means pin is inverted
     float senseFactor;
+    int senseOffset;
     unsigned int tripMilliamps;
     int rawCurrentTripValue;
+#if defined(ARDUINO_TEENSY40) || defined(ARDUINO_TEENSY41)
+    static bool disableInterrupts() {
+      uint32_t primask;
+      __asm__ volatile("mrs %0, primask\n" : "=r" (primask)::);
+      __disable_irq();
+      return (primask == 0) ? true : false;
+    }
+    static void enableInterrupts(bool doit) {
+      if (doit) __enable_irq();
+    }
+#endif
 };
 #endif

MotorDrivers.h

@@ -1,8 +1,27 @@
+/*
+ *  (c) 2020 Chris Harlow. All rights reserved.
+ *  (c) 2021 Fred Decker.  All rights reserved.
+ *  (c) 2020 Harald Barth. All rights reserved.
+ *  (c) 2020 Anthony W - Dayton. All rights reserved.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
 #ifndef MotorDrivers_h
 #define MotorDrivers_h
-#if defined(ARDUINO_ARCH_MEGAAVR)
 #include <Arduino.h>
-#endif
 
 // *** PLEASE NOTE *** THIS FILE IS  **NOT**  INTENDED TO BE EDITED WHEN CONFIGURING A SYSTEM.
 // It will be overwritten if the library is updated.
@@ -23,7 +42,7 @@
 // If the brakePin is negative that means the sense
 // of the brake pin on the motor bridge is inverted
 // (HIGH == release brake)
-
+//
 // Arduino standard Motor Shield
 #define STANDARD_MOTOR_SHIELD F("STANDARD_MOTOR_SHIELD"),                                                 \
                               new MotorDriver(3, 12, UNUSED_PIN, UNUSED_PIN, A0, 2.99, 2000, UNUSED_PIN), \
@@ -31,8 +50,8 @@
 
 // Pololu Motor Shield
 #define POLOLU_MOTOR_SHIELD F("POLOLU_MOTOR_SHIELD"),                                                 \
-                            new MotorDriver( 9, 7, UNUSED_PIN,         -4, A0, 18, 3000,         12), \
-                            new MotorDriver(10, 8, UNUSED_PIN, UNUSED_PIN, A1, 18, 3000, UNUSED_PIN)
+                            new MotorDriver( 9, 7, UNUSED_PIN,         -4, A0, 18, 3000, 12), \
+                            new MotorDriver(10, 8, UNUSED_PIN, UNUSED_PIN, A1, 18, 3000, 12)
 //
 // Actually, on the Pololu MC33926 shield the enable lines are tied together on pin 4 and the
 // pins 9 and 10 work as "inverted brake" but as we turn on and off the tracks individually
@@ -40,8 +59,8 @@
 // version of the code always will be high. That means this config is not usable for generating
 // a railcom cuotout in the future. For that one must wire the second ^D2 to pin 2 and define
 // the motor driver like this:
-//                          new MotorDriver(4, 7, UNUSED_PIN,  -9, A0, 18, 3000,         12)
-//                          new MotorDriver(2, 8, UNUSED_PIN, -10, A1, 18, 3000, UNUSED_PIN)
+//                          new MotorDriver(4, 7, UNUSED_PIN,  -9, A0, 18, 3000, 12)
+//                          new MotorDriver(2, 8, UNUSED_PIN, -10, A1, 18, 3000, 12)
 // See Pololu dial_mc33926_shield_schematic.pdf and truth table on page 17 of the MC33926 data sheet.
 
 // Firebox Mk1
@@ -59,4 +78,13 @@
                          new MotorDriver(10, 12, UNUSED_PIN, 9, A0, 2.99, 2000, UNUSED_PIN), \
                          new MotorDriver(11, 13, UNUSED_PIN, UNUSED_PIN, A1, 2.99, 2000, UNUSED_PIN)
 
+// IBT_2 Motor Board for Main and Arduino Motor Shield for Prog
+#define IBT_2_WITH_ARDUINO F("IBT_2_WITH_ARDUINO_SHIELD"),                                              \
+                         new MotorDriver(4, 5, 6, UNUSED_PIN, A5, 41.54, 5000, UNUSED_PIN), \
+                         new MotorDriver(11, 13, UNUSED_PIN, UNUSED_PIN, A1, 2.99, 2000, UNUSED_PIN)
+// YFROBOT Motor Shield (V3.1)
+#define YFROBOT_MOTOR_SHIELD F("YFROBOT_MOTOR_SHIELD"), \
+    new MotorDriver(5, 4, UNUSED_PIN, UNUSED_PIN, A0, 2.99, 2000, UNUSED_PIN), \
+    new MotorDriver(6, 7, UNUSED_PIN, UNUSED_PIN, A1, 2.99, 2000, UNUSED_PIN)
+
 #endif

Outputs.cpp

@@ -83,25 +83,46 @@ the state of any outputs being monitored or controlled by a separate interface o
 
 #include "Outputs.h"
 #include "EEStore.h"
+#include "StringFormatter.h"
+#include "IODevice.h"
 
+///////////////////////////////////////////////////////////////////////////////
+// Static function to print all output states to stream in the form "<Y id state>"
 
-void  Output::activate(int s){
-  data.oStatus=(s>0);                                               // if s>0, set status to active, else inactive
-  digitalWrite(data.pin,data.oStatus ^ bitRead(data.iFlag,0));      // set state of output pin to HIGH or LOW depending on whether bit zero of iFlag is set to 0 (ACTIVE=HIGH) or 1 (ACTIVE=LOW)
-  if(num>0)
-    EEPROM.put(num,data.oStatus);
+void Output::printAll(Print *stream){
+  for (Output *tt = Output::firstOutput; tt != NULL; tt = tt->nextOutput)
+    StringFormatter::send(stream, F("<Y %d %d>\n"), tt->data.id, tt->data.active);
+} // Output::printAll
+
+///////////////////////////////////////////////////////////////////////////////
+// Object method to activate / deactivate the Output state.
+
+void  Output::activate(uint16_t s){
+  s = (s>0);  // Make 0 or 1
+  data.active = s;                     // if s>0, set status to active, else inactive
+  // set state of output pin to HIGH or LOW depending on whether bit zero of iFlag is set to 0 (ACTIVE=HIGH) or 1 (ACTIVE=LOW)
+  IODevice::write(data.pin, s ^ data.invert);  
+
+  // Update EEPROM if output has been stored.    
+  if(EEStore::eeStore->data.nOutputs > 0 && num > 0)
+    EEPROM.put(num, data.oStatus);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
+// Static function to locate Output object specified by ID 'n'.
+//   Return NULL if not found.
 
-Output* Output::get(int n){
+Output* Output::get(uint16_t n){
   Output *tt;
   for(tt=firstOutput;tt!=NULL && tt->data.id!=n;tt=tt->nextOutput);
   return(tt);
 }
-///////////////////////////////////////////////////////////////////////////////
 
-bool Output::remove(int n){
+///////////////////////////////////////////////////////////////////////////////
+// Static function to delete Output object specified by ID 'n'.
+//   Return false if not found.
+
+bool Output::remove(uint16_t n){
   Output *tt,*pp=NULL;
 
   for(tt=firstOutput;tt!=NULL && tt->data.id!=n;pp=tt,tt=tt->nextOutput);
@@ -119,23 +140,26 @@ bool Output::remove(int n){
   }
 
 ///////////////////////////////////////////////////////////////////////////////
+// Static function to load configuration and state of all Outputs from EEPROM
 
 void Output::load(){
   struct OutputData data;
   Output *tt;
 
-  for(int i=0;i<EEStore::eeStore->data.nOutputs;i++){
+  for(uint16_t i=0;i<EEStore::eeStore->data.nOutputs;i++){
     EEPROM.get(EEStore::pointer(),data);
-    tt=create(data.id,data.pin,data.iFlag);
-    tt->data.oStatus=bitRead(tt->data.iFlag,1)?bitRead(tt->data.iFlag,2):data.oStatus;      // restore status to EEPROM value is bit 1 of iFlag=0, otherwise set to value of bit 2 of iFlag
-    digitalWrite(tt->data.pin,tt->data.oStatus ^ bitRead(tt->data.iFlag,0));
-    pinMode(tt->data.pin,OUTPUT);
-    tt->num=EEStore::pointer();
+    // Create new object, set current state to default or to saved state from eeprom.
+    tt=create(data.id, data.pin, data.flags);
+    uint8_t state = data.setDefault ? data.defaultValue : data.active;
+    tt->activate(state);
+
+    if (tt) tt->num=EEStore::pointer() + offsetof(OutputData, oStatus); // Save pointer to flags within EEPROM
     EEStore::advance(sizeof(tt->data));
   }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
+// Static function to store configuration and state of all Outputs to EEPROM
 
 void Output::store(){
   Output *tt;
@@ -144,19 +168,25 @@ void Output::store(){
   EEStore::eeStore->data.nOutputs=0;
 
   while(tt!=NULL){
-    tt->num=EEStore::pointer();
     EEPROM.put(EEStore::pointer(),tt->data);
+    tt->num=EEStore::pointer() + offsetof(OutputData, oStatus); // Save pointer to flags within EEPROM
     EEStore::advance(sizeof(tt->data));
     tt=tt->nextOutput;
     EEStore::eeStore->data.nOutputs++;
   }
 
 }
-///////////////////////////////////////////////////////////////////////////////
 
-Output *Output::create(int id, int pin, int iFlag, int v){
+///////////////////////////////////////////////////////////////////////////////
+// Static function to create an Output object
+//   The obscurely named parameter 'v' is 0 if called from the load() function
+//   and 1 if called from the <Z> command processing.
+
+Output *Output::create(uint16_t id, VPIN pin, int iFlag, int v){
   Output *tt;
 
+  if (pin > VPIN_MAX) return NULL;
+  
   if(firstOutput==NULL){
     firstOutput=(Output *)calloc(1,sizeof(Output));
     tt=firstOutput;
@@ -169,20 +199,21 @@ Output *Output::create(int id, int pin, int iFlag, int v){
   }
 
   if(tt==NULL) return tt;
-  
+  tt->num = 0; // make sure new object doesn't get written to EEPROM until store() command
   tt->data.id=id;
   tt->data.pin=pin;
-  tt->data.iFlag=iFlag;
-  tt->data.oStatus=0;
+  tt->data.flags=iFlag;
 
   if(v==1){
-    tt->data.oStatus=bitRead(tt->data.iFlag,1)?bitRead(tt->data.iFlag,2):0;      // sets status to 0 (INACTIVE) is bit 1 of iFlag=0, otherwise set to value of bit 2 of iFlag
-    digitalWrite(tt->data.pin,tt->data.oStatus ^ bitRead(tt->data.iFlag,0));
-    pinMode(tt->data.pin,OUTPUT);
+    // sets status to 0 (INACTIVE) is bit 1 of iFlag=0, otherwise set to value of bit 2 of iFlag
+    if (tt->data.setDefault) 
+      tt->data.active = tt->data.defaultValue;
+    else
+      tt->data.active = 0;
   }
+  IODevice::write(tt->data.pin, tt->data.active ^ tt->data.invert);
 
   return(tt);
-
 }
 
 ///////////////////////////////////////////////////////////////////////////////

Outputs.h

@@ -20,27 +20,43 @@
 #define Outputs_h
 
 #include <Arduino.h>
+#include "IODevice.h"
 
 struct OutputData {
-  uint8_t oStatus;
-  uint8_t id;
-  uint8_t pin; 
-  uint8_t iFlag; 
+  union {
+    uint8_t oStatus;      // (Bit 0=Invert, Bit 1=Set state to default, Bit 2=default state, Bit 7=active)
+    struct {
+      unsigned int flags : 7; // Bit 0=Invert, Bit 1=Set state to default, Bit 2=default state
+      unsigned int : 1;
+    };
+    struct {
+      unsigned int invert : 1;
+      unsigned int setDefault : 1;
+      unsigned int defaultValue : 1;
+      unsigned int: 4;
+      unsigned int active : 1;
+    };
+  };
+  uint16_t id;
+  VPIN pin; 
 };
 
+
 class Output{
-  public:
-  void activate(int s);
-  static Output* get(int);
-  static bool remove(int);
+public:
+  void activate(uint16_t s);
+  bool isActive();
+  static Output* get(uint16_t);
+  static bool remove(uint16_t);
   static void load();
   static void store();
-  static Output *create(int, int, int, int=0);
+  static Output *create(uint16_t, VPIN, int, int=0);
   static Output *firstOutput;
   struct OutputData data;
   Output *nextOutput;
-  private:
-  int num;  // Chris has no idea what this is all about!
+  static void printAll(Print *);
+private:
+  uint16_t num;  // EEPROM address of oStatus in OutputData struct, or zero if not stored.
   
 }; // Output
   

PWMServoDriver.cpp

@@ -1,102 +0,0 @@
-
-
-/*!
- *  @file PWMServoDriver.cpp
- *
- *  @mainpage Adafruit 16-channel PWM & Servo driver, based on Adafruit_PWMServoDriver
- *
- *  @section intro_sec Introduction
- *
- *  This is a library for the 16-channel PWM & Servo driver.
- *
- *  Designed specifically to work with the Adafruit PWM & Servo driver.
- *  This class contains a very small subset of the Adafruit version which
- *  is relevant to driving simple servos at 50Hz through a number of chained 
- *  servo driver boards (ie servos 0-15 on board 0x40, 16-31 on board 0x41 etc.)
- *  
- *  @section author Author
- *  Chris Harlow (TPL) 
- *  original by Limor Fried/Ladyada (Adafruit Industries).
- *
- *  @section license License
- *
- *  BSD license, all text above must be included in any redistribution
- */
-#include <Arduino.h>
-#include <Wire.h>
-#include "PWMServoDriver.h"
-#include "DIAG.h"
-
-
-// REGISTER ADDRESSES
-const byte PCA9685_MODE1=0x00;      // Mode Register 
-const byte PCA9685_FIRST_SERVO=0x06;  /** low byte first servo register ON*/
-const byte PCA9685_PRESCALE=0xFE;     /** Prescale register for PWM output frequency */
-// MODE1 bits
-const byte MODE1_SLEEP=0x10;   /**< Low power mode. Oscillator off */
-const byte MODE1_AI=0x20;      /**< Auto-Increment enabled */
-const byte MODE1_RESTART=0x80; /**< Restart enabled */
-
-const byte PCA9685_I2C_ADDRESS=0x40;      /** First PCA9685 I2C Slave Address */
-const float FREQUENCY_OSCILLATOR=25000000.0; /** Accurate enough for our purposes  */
-const uint8_t PRESCALE_50HZ = (uint8_t)(((FREQUENCY_OSCILLATOR / (50.0 * 4096.0)) + 0.5) - 1);
-  
-/*!
- *  @brief  Sets the PWM frequency for a chip to 50Hz for servos
- */
-
-byte PWMServoDriver::setupFlags=0;  // boards that have been initialised
-byte PWMServoDriver::failFlags=0;  // boards that have faild initialisation
-
-bool PWMServoDriver::setup(int board) {
-  if (board>3 || (failFlags & (1<<board))) return false; 
-  if (setupFlags & (1<<board)) return true; 
-  
-  Wire.begin();
-  uint8_t i2caddr=PCA9685_I2C_ADDRESS + board;
-
-  // Terst if device is available
-  Wire.beginTransmission(i2caddr);
-  byte error = Wire.endTransmission();
-  if (error!=0) {
-    DIAG(F("\nI2C Servo device 0x%x Not Found %d\n"),i2caddr, error);
-    failFlags|=1<<board;  
-    return false;
-  }
-    
-  //DIAG(F("\nPWMServoDriver::setup %x prescale=%d"),i2caddr,PRESCALE_50HZ); 
-  writeRegister(i2caddr,PCA9685_MODE1, MODE1_SLEEP | MODE1_AI);    
-  writeRegister(i2caddr,PCA9685_PRESCALE, PRESCALE_50HZ);  
-  writeRegister(i2caddr,PCA9685_MODE1,MODE1_AI);
-  writeRegister(i2caddr,PCA9685_MODE1,  MODE1_RESTART | MODE1_AI);
-  setupFlags|=1<<board;
-  return true;
-}
-
-/*!
- *  @brief  Sets the PWM output to a servo
- */
-void PWMServoDriver::setServo(byte servoNum, uint16_t value) {
-  int board=servoNum/16; 
-  int pin=servoNum%16;
-  
-  if (setup(board)) {
-    DIAG(F("\nSetServo %d %d\n"),servoNum,value);  
-    Wire.beginTransmission(PCA9685_I2C_ADDRESS + board);
-    Wire.write(PCA9685_FIRST_SERVO + 4 * pin); // 4 registers per pin
-    Wire.write(0);
-    Wire.write(0);
-    Wire.write(value);
-    Wire.write(value >> 8);
-    byte error=Wire.endTransmission();
-    if (error!=0) DIAG(F("\nSetServo error %d\n"),error); 
-  }
-}
-
-void PWMServoDriver::writeRegister(uint8_t i2caddr,uint8_t hardwareRegister, uint8_t d) {
-  Wire.beginTransmission(i2caddr);
-  Wire.write(hardwareRegister);
-  Wire.write(d);
-  Wire.endTransmission();
-  delay(5); // allow registers to settle before continuing
-}

PWMServoDriver.h

@@ -1,21 +0,0 @@
-/*!
- *  @file PWMServoDriver.h
- *
- *  Used to set servo positions on an I2C bus with 1 or more PCA96685 boards.
- */
-#ifndef PWMServoDriver_H
-#define PWMServoDriver_H
-
-
-class PWMServoDriver {
-public:
-    static void setServo(byte servoNum,  uint16_t pos);
-    
-private:
-  static byte setupFlags; 
-  static byte failFlags; 
-  static bool setup(int board);
-  static void writeRegister(uint8_t i2caddr,uint8_t hardwareRegister, uint8_t d);
-};
-
-#endif

README.md

@@ -1,52 +1,77 @@
-# What's DCC++ EX
-------------
+# What is DCC++ EX?
+DCC++ EX is the organization maintaining several codebases that together represent a fully open source DCC system. Currently, this includes the following:
 
-DCC++ EX is an open-source hardware and software system for the operation of DCC-equipped model railroads. It expands on the work of Gregg E. Berman's original DCC++ (which can be found here in the BaseStation-Classic repository)
+* [CommandStation-EX](https://github.com/DCC-EX/CommandStation-EX/releases) - the latest take on the DCC++ command station for controlling your trains. Runs on an Arduino board, and includes advanced features such as a WiThrottle server implementation, turnout operation, general purpose inputs and outputs (I/O), and JMRI integration.
+* [exWebThrottle](https://github.com/DCC-EX/exWebThrottle) - a simple web based controller for your DCC++ command station.
+* [BaseStation-installer](https://github.com/DCC-EX/BaseStation-Installer) - an installer executable that takes care of downloading and installing DCC++ firmware onto your hardware setup.
+* [BaseStation-Classic](https://github.com/DCC-EX/BaseStation-Classic) - the original DCC++ software, packaged in a stable release. No active development, bug fixes only.
 
-The system consists of two parts, the DCC++ EX Command Station and one of many front end controllers. These controllers can be hardware controllers (called CABs or Throttles), software applications like JMRI, phone apps like Engine Driver, or our exWebThrottle that is a simple application you run in a browser like a web page and control your model trains.
+A basic DCC++ EX hardware setup can use easy to find, widely avalable Arduino boards that you can assemble yourself.
 
-The DCC++ EX Command Station consists of an Arduino micro controller fitted with an Arduino Motor Shield (or other supported motor controllers) that can be connected directly to the tracks of a model railroad.
+Both CommandStation-EX and BaseStation-Classic support much of the NMRA Digital Command Control (DCC) [standards](http://www.nmra.org/dcc-working-group "NMRA DCC Working Group"), including:
 
-# What’s in this Repository
--------------------------
+* simultaneous control of multiple locomotives
+* 2-byte and 4-byte locomotive addressing
+* 28 or 128-step speed throttling
+* Activate/de-activate all accessory function addresses 0-2048
+* Control of all cab functions F0-F28 and F29-F68
+* Main Track: Write configuration variable bytes and set/clear specific configuration variable (CV) bits (aka Programming on Main or POM)
+* Programming Track: Same as the main track with the addition of reading configuration variable bytes
+* And manu more custom features. see [What's new in CommandStation-EX?](#whats-new-in-commandstation-ex)
 
-This repository, CommandStation-EX, contains a complete DCC++ EX Commmand Station sketch designed for compiling and uploading into an Arduino Uno, Mega, or Nano.  All sketch files are in the folder named CommandStation-EX and its subforlders. More information about the sketch can be found in the included PDF file.
 
-To utilize this sketch, you can use the following methods: 
+# What’s in this Repository?
 
-* our automated installer
-* download a zip file from this repository (green Code button above) and unzip it
-* use git clone on this repository
+This repository, CommandStation-EX, contains a complete DCC++ EX Commmand Station sketch designed for compiling and uploading into an Arduino Uno, Mega, or Nano.  All sketch files are in the folder named CommandStation-EX and its subforlders. 
 
-With the manual methods you unzip or git clone to the Arduino IDE
-projects folder and then open the file "CommandStation-EX.ino" in the
+To utilize this sketch, you can use the following: 
+
+1. (beginner) our [automated installer](https://github.com/DCC-EX/BaseStation-Installer)
+2. (intermediate) download the latest version from the [releases page](https://github.com/DCC-EX/CommandStation-EX/releases)
+3. (advanced) use git clone on this repository 
+
+Not using the installer? Open the file "CommandStation-EX.ino" in the
 Arduino IDE. Please do not rename the folder containing the sketch
 code, nor add any files in that folder. The Arduino IDE relies on the
 structure and name of the folder to properly display and compile the
-code. If you do not run the installer, you have to copy
-config.example.h to config.h. If you do not have the standard config
-you edit config.h according to the help texts in config.h.
+code. Rename or copy config.example.h to config.h. If you do not have 
+the standard setup, you must edit config.h according to the help texts 
+in config.h.
 
-The latest production release of the Master branch is 3.0.1:
+## What's new in CommandStation-EX?
 
-* Supports the Arduino Uno, Arduino Mega, and Arduino Nano
-* Built-in configuration for both the original Arduino Motor Shield, Pololu MC33926 Motor Shield, LMD18200, and BTS7960B
-* Built-in configuration and support of Ethernet Shields and the ESP82266 WiFi module (networking for use with Mega only).
+* WiThrottle server built in. Connect Engine Driver or WiThrottle clients directly to your Command Station (or through JMRI as before)
+* WiFi and Ethernet shield support
+* No more jumpers or soldering!
+* Direct support for all the most popular motor control boards including single pin (Arduino) or dual pin (IBT_2) type PWM inputs without the need for an adapter circuit
+* I2C Display support (LCD and OLED)
+* Improved short circuit detection and automatic reset from an overload
+* Current reading, sensing and ACK detection settings in milliAmps instead of just pin readings
+* Improved adherence to the NMRA DCC specification
+* Complete support for all the old commands and front ends like JMRI
+* Railcom cutout (beta)
+* Simpler, modular, faster code with an API Library for developers for easy expansion
+* New features and functions in JMRI
+* Ability to join MAIN and PROG tracks into one MAIN track to run your locos
+* "Drive-Away" feature - Throttles with support, like Engine Driver, can allow a loco to be programmed on a usable, electrically isolated programming track and then drive off onto the main track
+* Diagnostic commands to test decoders that aren't reading or writing correctly
+* Support for Uno, Nano, Mega, Nano Every and Teensy microcontrollers
+* User Functions: Filter regular commands (like a turnout or output command) and pass it to your own function or accessory
+* Support for LCN (layout control nodes)
+* mySetup.h file that acts like an Autoexec.Bat command to send startup commands to the CS
+* High Accuracty Waveform option for rock steady DCC signals
+* New current response outputs current in mA, overlimit current, and maximum board capable current. Support for new current meter in JMRI
+* USB Browser based EX-WebThrottle
+* New, simpler, function control command
+* Number of locos discovery command `<#>`
+* Emergency stop command <!>
+* Release cabs from memory command <-> all cabs, <- CAB> for just one loco address
+* Automatic slot (register) management 
+* Automation (coming soon)
 
-For more information on the overall DCC++ EX system, please follow the links in the PDF file.
+NOTE: DCC-EX is a major rewrite to the code. We started over and rebuilt it from the ground up! For what that means to you, click [HERE](notes/rewrite.md).
 
-Detailed diagrams showing pin mappings and required jumpers for the Motor Shields can be found in the Documentation Repository
+# More information
+You can learn more at the [DCC++ EX website](https://dcc-ex.com/)
 
-The Master branch contains all of the Command Station functionality showed in the DCC-EX YouTube channel.
-
-# How to find more information
---------------------------
-
-[DCC++ EX WEB Page](https://dcc-ex.github.io "DCC++ EX WEB Page")
-
-[The DCC++ EX Discord and live support](https://discord.gg/y2sB4Fp "The DCC++ EX Discord Server")
-
-[TrainBoard DCC++ Forum](https://www.trainboard.com/highball/index.php?forums/dcc.177/ "TrainBoard DCC++ Forum")
-
--May 2020
-!!
+- November 14, 2020

RMFT.h

@@ -0,0 +1,23 @@
+#ifndef RMFT_H
+#define RMFT_H
+
+#if defined(RMFT_ACTIVE)
+ #include "RMFT2.h"
+
+  class RMFT {
+    public:
+      static void inline begin() {RMFT2::begin();}
+      static void inline loop() {RMFT2::loop();}
+  };
+
+  #include "RMFTMacros.h"
+  
+#else 
+  // Dummy RMFT 
+  class RMFT {
+    public:
+      static void inline begin() {}
+      static void inline loop() {}
+  };
+#endif
+#endif

RMFT2.cpp

@@ -0,0 +1,769 @@
+/*
+ *  © 2020,2021 Chris Harlow. All rights reserved.
+ *  
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#include <Arduino.h>
+#include "RMFT2.h"
+#include "DCC.h"
+#include "DCCWaveform.h"
+#include "DIAG.h"
+#include "WiThrottle.h"
+#include "DCCEXParser.h"
+#include "Turnouts.h"
+
+
+// Command parsing keywords
+const int16_t HASH_KEYWORD_EXRAIL=15435;    
+const int16_t HASH_KEYWORD_ON = 2657;
+const int16_t HASH_KEYWORD_START=23232;
+const int16_t HASH_KEYWORD_RESERVE=11392;
+const int16_t HASH_KEYWORD_FREE=-23052;
+const int16_t HASH_KEYWORD_LATCH=1618;  
+const int16_t HASH_KEYWORD_UNLATCH=1353;
+const int16_t HASH_KEYWORD_PAUSE=-4142;
+const int16_t HASH_KEYWORD_RESUME=27609;
+const int16_t HASH_KEYWORD_KILL=5218;
+const int16_t HASH_KEYWORD_ROUTES=-3702;
+
+// One instance of RMFT clas is used for each "thread" in the automation.
+// Each thread manages a loco on a journey through the layout, and/or may manage a scenery automation.
+// The thrrads exist in a ring, each time through loop() the next thread in the ring is serviced.
+
+// Statics 
+const int16_t LOCO_ID_WAITING=-99; // waiting for loco id from prog track
+int16_t RMFT2::progtrackLocoId;  // used for callback when detecting a loco on prograck
+bool RMFT2::diag=false;      // <D EXRAIL ON>  
+RMFT2 * RMFT2::loopTask=NULL; // loopTask contains the address of ONE of the tasks in a ring.
+RMFT2 * RMFT2::pausingTask=NULL; // Task causing a PAUSE.
+ // when pausingTask is set, that is the ONLY task that gets any service,
+ // and all others will have their locos stopped, then resumed after the pausing task resumes.
+byte RMFT2::flags[MAX_FLAGS];
+
+#define GET_OPCODE GETFLASH(RMFT2::RouteCode+progCounter)
+#define GET_OPERAND(n) GETFLASHW(RMFT2::RouteCode+progCounter+1+(n*3))
+#define SKIPOP progCounter+=3
+
+/* static */ void RMFT2::begin() { 
+  DCCEXParser::setRMFTFilter(RMFT2::ComandFilter);
+  for (int f=0;f<MAX_FLAGS;f++) flags[f]=0;
+  int progCounter;
+  // first pass startup, define any turnouts or servos, set signals red and count size.
+  for (progCounter=0;; SKIPOP){
+     byte opcode=GET_OPCODE;
+     if (opcode==OPCODE_ENDEXRAIL) break;
+
+     switch (opcode) {
+     case OPCODE_AT:
+     case OPCODE_AFTER:
+     case OPCODE_IF:
+     case OPCODE_IFNOT:
+       int16_t pin = (int16_t)GET_OPERAND(0);
+       if (pin<0) pin = -pin;
+       IODevice::configureInput((VPIN)pin,true);
+     }
+
+     if (opcode==OPCODE_SIGNAL) {
+      VPIN red=GET_OPERAND(0);
+      VPIN amber=GET_OPERAND(1);
+      VPIN green=GET_OPERAND(2);
+      IODevice::write(red,true);
+      if (amber) IODevice::write(amber,false);
+      IODevice::write(green,false);
+      continue;
+     }
+     
+     if (opcode==OPCODE_TURNOUT) {
+      VPIN id=GET_OPERAND(0);
+      int addr=GET_OPERAND(1);
+      byte subAddr=GET_OPERAND(2);
+      DCCTurnout::create(id,addr,subAddr);
+      continue;
+     }
+
+     if (opcode==OPCODE_SERVOTURNOUT) {
+      int16_t id=GET_OPERAND(0);
+      VPIN pin=GET_OPERAND(1);
+      int activeAngle=GET_OPERAND(2);
+      int inactiveAngle=GET_OPERAND(3);
+      int profile=GET_OPERAND(4);
+      ServoTurnout::create(id,pin,activeAngle,inactiveAngle,profile);
+      continue;
+     }
+
+     if (opcode==OPCODE_PINTURNOUT) {
+      int16_t id=GET_OPERAND(0);
+      VPIN pin=GET_OPERAND(1);
+      VpinTurnout::create(id,pin);
+      continue;
+     }
+     // other opcodes are not needed on this pass
+  } 
+  SKIPOP; // include ENDROUTES opcode
+  DIAG(F("EXRAIL %db, MAX_FLAGS=%d"), progCounter,MAX_FLAGS);
+  new RMFT2(0); // add the startup route
+}
+
+// This filter intercepts <> commands to do the following:
+// - Implement RMFT specific commands/diagnostics 
+// - Reject/modify JMRI commands that would interfere with RMFT processing 
+void RMFT2::ComandFilter(Print * stream, byte & opcode, byte & paramCount, int16_t p[]) {
+    (void)stream; // avoid compiler warning if we don't access this parameter 
+    bool reject=false;
+    switch(opcode) {
+        
+     case 'D':
+        if (p[0]==HASH_KEYWORD_EXRAIL) { // <D EXRAIL ON/OFF>
+           diag = paramCount==2 && (p[1]==HASH_KEYWORD_ON || p[1]==1);
+           opcode=0;
+        }
+        break;
+          
+     case '/':  // New EXRAIL command
+          reject=!parseSlash(stream,paramCount,p);
+          opcode=0;
+          break;
+          
+     default:  // other commands pass through 
+     break;       
+   }
+ if (reject) {
+   opcode=0;
+   StringFormatter::send(stream,F("<X>"));
+   }
+}
+     
+bool RMFT2::parseSlash(Print * stream, byte & paramCount, int16_t p[]) {
+
+          if (paramCount==0) { // STATUS
+                 StringFormatter::send(stream, F("<* EXRAIL STATUS"));
+                 RMFT2 * task=loopTask;
+                 while(task) {
+                   StringFormatter::send(stream,F("\nID=%d,PC=%d,LOCO=%d%c,SPEED=%d%c"),
+                         (int)(task->taskId),task->progCounter,task->loco,
+                         task->invert?'I':' ',
+                         task->speedo, 
+                         task->forward?'F':'R'
+                         );
+                   task=task->next;      
+                   if (task==loopTask) break;      
+                 }
+                 // Now stream the flags 
+                 for (int id=0;id<MAX_FLAGS; id++) {
+                   byte flag=flags[id];
+                   if (flag & ~TASK_FLAG) { // not interested in TASK_FLAG only. Already shown above 
+                     StringFormatter::send(stream,F("\nflags[%d} "),id);
+                     if (flag & SECTION_FLAG) StringFormatter::send(stream,F(" RESERVED"));
+                     if (flag & LATCH_FLAG) StringFormatter::send(stream,F(" LATCHED"));
+                     }                 
+                 }
+                 StringFormatter::send(stream,F(" *>\n"));
+                 return true;
+            }
+          switch (p[0]) {
+            case HASH_KEYWORD_PAUSE: // </ PAUSE>
+                 if (paramCount!=1) return false;
+                 DCC::setThrottle(0,1,true);  // pause all locos on the track         
+                 pausingTask=(RMFT2 *)1; // Impossible task address
+                 return true;
+                 
+            case HASH_KEYWORD_RESUME: // </ RESUME>
+                 if (paramCount!=1) return false;
+                 pausingTask=NULL;
+                 {
+                  RMFT2 * task=loopTask;                 
+                  while(task) {
+                      if (task->loco) task->driveLoco(task->speedo);
+                      task=task->next;      
+                      if (task==loopTask) break;      
+                    }
+                 }        
+                 return true;
+                 
+                      
+            case HASH_KEYWORD_START: // </ START [cab] route >
+                 if (paramCount<2 || paramCount>3) return false;
+                 {
+                  int route=(paramCount==2) ? p[1] : p[2];
+                  uint16_t cab=(paramCount==2)? 0 : p[1];
+                  int pc=locateRouteStart(route);                 
+                  if (pc<0) return false;
+                    RMFT2* task=new RMFT2(pc);
+                    task->loco=cab;                    
+                 }
+              return true;
+
+            case HASH_KEYWORD_ROUTES: // </ ROUTES > JMRI withrottle support 
+                 if (paramCount>1) return false;
+                 StringFormatter::send(stream,F("</ROUTES "));
+                 emitWithrottleRouteList(stream);                                  
+                 StringFormatter::send(stream,F(">"));
+              return true;
+              
+            default:
+              break;
+          }
+          
+          // all other / commands take 1 parameter 0 to MAX_FLAGS-1     
+
+          if (paramCount!=2 || p[1]<0  || p[1]>=MAX_FLAGS) return false;
+
+          switch (p[0]) {  
+               case HASH_KEYWORD_KILL: // Kill taskid
+                    {
+                    RMFT2 * task=loopTask;
+                    while(task) {
+                      if (task->taskId==p[1]) {
+                         delete task;
+                         return  true;
+                      }
+                      task=task->next;      
+                      if (task==loopTask) break;      
+                    }
+                 }
+                 return false;
+                    
+            case HASH_KEYWORD_RESERVE:  // force reserve a section
+                 setFlag(p[1],SECTION_FLAG);
+                 return true;
+    
+            case HASH_KEYWORD_FREE:  // force free a section
+                 setFlag(p[1],0,SECTION_FLAG);
+                 return true;
+                
+            case HASH_KEYWORD_LATCH:
+                 setFlag(p[1], LATCH_FLAG);
+                 return true;
+   
+            case HASH_KEYWORD_UNLATCH:
+                 setFlag(p[1], 0, LATCH_FLAG);
+                 return true;
+                  
+            default:
+                 return false;                 
+          }
+    }
+
+
+// This emits Routes and Automations to Withrottle
+// Automations are given a state to set the button to "handoff" which implies 
+// handing over the loco to the automation.
+// Routes are given "Set" buttons and do not cause the loco to be handed over. 
+void RMFT2::emitWithrottleRouteList(Print* stream) {
+   StringFormatter::send(stream,F("PRT]\\[Routes}|{Route]\\[Set}|{2]\\[Handoff}|{4\nPRL"));
+   emitWithrottleDescriptions(stream);
+   StringFormatter::send(stream,F("\n"));
+}
+
+
+RMFT2::RMFT2(int progCtr) {
+  progCounter=progCtr;
+
+  // get an unused  task id from the flags table 
+  taskId=255; // in case of overflow
+  for (int f=0;f<MAX_FLAGS;f++) {
+    if (!getFlag(f,TASK_FLAG)) {
+      taskId=f;
+      setFlag(f, TASK_FLAG);
+      break;
+    }
+  }
+  delayTime=0;
+  loco=0;
+  speedo=0;
+  forward=true;
+  invert=false;
+  stackDepth=0;
+  onTurnoutId=0; // Not handling an ONTHROW/ONCLOSE
+   
+  // chain into ring of RMFTs
+  if (loopTask==NULL) {
+    loopTask=this;
+    next=this;
+  }
+  else {
+        next=loopTask->next;
+        loopTask->next=this;
+  }
+}
+
+
+RMFT2::~RMFT2() {
+  driveLoco(1); // ESTOP my loco if any 
+  setFlag(taskId,0,TASK_FLAG); // we are no longer using this id
+  if (next==this) loopTask=NULL;
+  else for (RMFT2* ring=next;;ring=ring->next) if (ring->next == this) {
+           ring->next=next;
+           loopTask=next;
+           break;
+       }
+}
+
+void RMFT2::createNewTask(int route, uint16_t cab) {
+      int pc=locateRouteStart(route);
+      if (pc<0) return;
+      RMFT2* task=new RMFT2(pc);
+      task->loco=cab;
+}
+
+   
+int RMFT2::locateRouteStart(int16_t _route) {
+  if (_route==0) return 0; // Route 0 is always start of ROUTES for default startup 
+  for (int progCounter=0;;SKIPOP) {
+    byte opcode=GET_OPCODE;
+    if (opcode==OPCODE_ENDEXRAIL) {
+      DIAG(F("RMFT2 sequence %d not found"), _route);
+      return -1;
+    }
+    if ((opcode==OPCODE_ROUTE || opcode==OPCODE_AUTOMATION || opcode==OPCODE_SEQUENCE) 
+       &&  _route==(int)GET_OPERAND(0)) return progCounter;
+  }
+  return -1;
+}
+
+
+void RMFT2::driveLoco(byte speed) {
+     if (loco<=0) return;  // Prevent broadcast! 
+     if (diag) DIAG(F("EXRAIL drive %d %d %d"),loco,speed,forward^invert);
+     if (DCCWaveform::mainTrack.getPowerMode()==POWERMODE::OFF) {
+        DCCWaveform::mainTrack.setPowerMode(POWERMODE::ON); 
+        Serial.println(F("<p1>")); // tell JMRI
+     }
+     DCC::setThrottle(loco,speed, forward^invert);
+     speedo=speed;
+}
+
+bool RMFT2::readSensor(uint16_t sensorId) {
+  // Exrail operands are unsigned but we need the signed version as inserted by the macros.  
+  int16_t sId=(int16_t) sensorId;
+
+  VPIN vpin=abs(sId);
+  if (getFlag(vpin,LATCH_FLAG)) return true; // latched on
+
+  // negative sensorIds invert the logic (e.g. for a break-beam sensor which goes OFF when detecting)
+  bool s= IODevice::read(vpin) ^ (sId<0);
+  if (s && diag) DIAG(F("EXRAIL Sensor %d hit"),sId);
+  return s;
+}
+
+bool RMFT2::skipIfBlock() {
+  // returns false if killed
+  short nest = 1;
+  while (nest > 0) {
+    SKIPOP;
+    byte opcode =  GET_OPCODE;
+    switch(opcode) {
+      case OPCODE_ENDEXRAIL: 
+           kill(F("missing ENDIF"), nest);
+           return false;  
+      case OPCODE_IF:
+      case OPCODE_IFNOT:
+      case OPCODE_IFRANDOM:
+      case OPCODE_IFRESERVE:
+           nest++;
+           break;
+      case OPCODE_ENDIF:
+           nest--;
+           break;
+      default:
+      break;
+    }
+  }
+  return true; 
+}
+
+
+
+/* static */ void RMFT2::readLocoCallback(int16_t cv) {
+     progtrackLocoId=cv;
+}
+
+void RMFT2::loop() {
+  
+  // Round Robin call to a RMFT task each time 
+     if (loopTask==NULL) return; 
+     
+     loopTask=loopTask->next;
+ 
+     if (pausingTask==NULL || pausingTask==loopTask) loopTask->loop2();
+}    
+
+  
+void RMFT2::loop2() {
+   if (delayTime!=0 && millis()-delayStart < delayTime) return;
+     
+  byte opcode = GET_OPCODE;
+  int16_t operand =  GET_OPERAND(0);
+  // if (diag) DIAG(F("RMFT2 %d %d"),opcode,operand); 
+  // Attention: Returning from this switch leaves the program counter unchanged.
+  //            This is used for unfinished waits for timers or sensors.
+  //            Breaking from this switch will step to the next step in the route. 
+  switch ((OPCODE)opcode) {
+    
+    case OPCODE_THROW:
+         Turnout::setClosed(operand, false);
+         break;
+          
+    case OPCODE_CLOSE:
+         Turnout::setClosed(operand, true);
+         break; 
+    
+    case OPCODE_REV:
+      forward = false;
+      driveLoco(operand);
+      break;
+    
+    case OPCODE_FWD:
+      forward = true;
+      driveLoco(operand);
+      break;
+      
+    case OPCODE_SPEED:
+      driveLoco(operand);
+      break;
+    
+    case OPCODE_INVERT_DIRECTION:
+      invert= !invert;
+      driveLoco(speedo);
+      break;
+      
+    case OPCODE_RESERVE:
+      if (getFlag(operand,SECTION_FLAG)) {
+        driveLoco(0);
+        delayMe(500);
+        return;
+      }
+      setFlag(operand,SECTION_FLAG);
+      break;
+    
+    case OPCODE_FREE:
+      setFlag(operand,0,SECTION_FLAG);
+      break;
+    
+    case OPCODE_AT:
+      if (readSensor(operand)) break;
+      delayMe(50);
+      return;
+    
+    case OPCODE_AFTER: // waits for sensor to hit and then remain off for 0.5 seconds. (must come after an AT operation)
+      if (readSensor(operand)) {
+        // reset timer to half a second and keep waiting
+        waitAfter=millis();
+        delayMe(50);
+        return; 
+      }
+      if (millis()-waitAfter < 500 ) return;   
+      break;
+    
+    case OPCODE_LATCH:
+      setFlag(operand,LATCH_FLAG);
+      break;
+    
+    case OPCODE_UNLATCH:
+      setFlag(operand,0,LATCH_FLAG);
+      break;
+
+    case OPCODE_SET:
+      IODevice::write(operand,true);
+      break;
+  
+    case OPCODE_RESET:
+      IODevice::write(operand,false);
+      break;
+    
+    case OPCODE_PAUSE:
+         DCC::setThrottle(0,1,true);  // pause all locos on the track
+         pausingTask=this;
+         break;
+
+    case OPCODE_POM:
+        if (loco) DCC::writeCVByteMain(loco, operand, GET_OPERAND(1));
+        break;
+
+    case OPCODE_POWEROFF:
+        DCCWaveform::mainTrack.setPowerMode(POWERMODE::OFF);
+        DCCWaveform::progTrack.setPowerMode(POWERMODE::OFF);
+        DCC::setProgTrackSyncMain(false);       
+        Serial.println(F("<p0>")); // Tell JMRI
+        break;
+
+    case OPCODE_RESUME:
+         pausingTask=NULL;
+         driveLoco(speedo);
+         for (RMFT2 * t=next; t!=this;t=t->next) if (t->loco >0) t->driveLoco(t->speedo);
+          break;        
+    
+    case OPCODE_IF: // do next operand if sensor set
+      if (!readSensor(operand)) if (!skipIfBlock()) return;
+      break;
+    
+    case OPCODE_IFNOT: // do next operand if sensor not set
+      if (readSensor(operand)) if (!skipIfBlock()) return;
+      break;
+   
+    case OPCODE_IFRANDOM: // do block on random percentage
+      if (random(100)>=operand) if (!skipIfBlock()) return;
+      break;
+   
+    case OPCODE_IFRESERVE: // do block if we successfully RERSERVE
+      if (!getFlag(operand,SECTION_FLAG)) setFlag(operand,SECTION_FLAG);
+      else if (!skipIfBlock()) return;
+      break;
+      
+    case OPCODE_ENDIF:
+      break;
+    
+    case OPCODE_DELAY:
+      delayMe(operand*100L);
+      break;
+   
+    case OPCODE_DELAYMINS:
+      delayMe(operand*60L*1000L);
+      break;
+    
+    case OPCODE_RANDWAIT:
+      delayMe(random(operand)*100L);
+      break;
+    
+    case OPCODE_RED:
+      doSignal(operand,true,false,false);
+      break;
+    
+    case OPCODE_AMBER:
+      doSignal(operand,false,true,false);
+      break;
+    
+    case OPCODE_GREEN:
+      doSignal(operand,false,false,true);
+      break;
+       
+    case OPCODE_FON:      
+      if (loco) DCC::setFn(loco,operand,true);
+      break;
+     
+    case OPCODE_FOFF:
+      if (loco) DCC::setFn(loco,operand,false);
+      break;
+    
+    case OPCODE_XFON:      
+      DCC::setFn(operand,GET_OPERAND(1),true);
+      break;
+   
+    case OPCODE_XFOFF:      
+      DCC::setFn(operand,GET_OPERAND(1),false);
+      break;
+   
+    case OPCODE_FOLLOW:
+      progCounter=locateRouteStart(operand);
+      if (progCounter<0) kill(F("FOLLOW unknown"), operand); 
+      return;
+  
+    case OPCODE_CALL:
+      if (stackDepth==MAX_STACK_DEPTH) {
+        kill(F("CALL stack"), stackDepth);
+        return;
+      }
+      callStack[stackDepth++]=progCounter+3;
+      progCounter=locateRouteStart(operand);
+      if (progCounter<0) kill(F("CALL unknown"),operand); 
+      return;
+
+    case OPCODE_RETURN:
+      if (stackDepth==0) {
+        kill(F("RETURN stack"));
+        return;
+      }
+      progCounter=callStack[--stackDepth];
+      return;
+      
+    case OPCODE_ENDTASK:
+    case OPCODE_ENDEXRAIL:
+      kill();
+      return;
+      
+    case OPCODE_JOIN:
+       DCCWaveform::mainTrack.setPowerMode(POWERMODE::ON); 
+       DCCWaveform::progTrack.setPowerMode(POWERMODE::ON); 
+       DCC::setProgTrackSyncMain(true);
+       Serial.println(F("<p1 JOIN>")); // Tell JMRI
+       break;
+
+    case OPCODE_UNJOIN:
+       DCC::setProgTrackSyncMain(false);
+       break;
+       
+    case OPCODE_READ_LOCO1: // READ_LOCO is implemented as 2 separate opcodes
+       progtrackLocoId=LOCO_ID_WAITING;  // Nothing found yet
+       DCC::getLocoId(readLocoCallback);
+       break;
+      
+      case OPCODE_READ_LOCO2:
+       if (progtrackLocoId==LOCO_ID_WAITING) {
+        delayMe(100);
+        return; // still waiting for callback
+       }
+       if (progtrackLocoId<0) {
+        kill(F("No Loco Found"),progtrackLocoId);
+        return; // still waiting for callback
+       }
+       
+       loco=progtrackLocoId;
+       speedo=0;
+       forward=true;
+       invert=false;
+       break;
+       
+       case OPCODE_START:
+           {
+            int newPc=locateRouteStart(operand);
+            if (newPc<0) break; 
+            new RMFT2(newPc); 
+           }
+           break;
+           
+      case OPCODE_SENDLOCO:  // cab, route
+           {
+            int newPc=locateRouteStart(GET_OPERAND(1));
+            if (newPc<0) break; 
+            RMFT2* newtask=new RMFT2(newPc); // create new task 
+            newtask->loco=operand; 
+           }
+           break;
+           
+       case OPCODE_SETLOCO:
+           {
+             loco=operand; 
+             speedo=0;
+             forward=true;
+             invert=false;
+            }
+       break;
+
+          
+       case OPCODE_SERVO: // OPCODE_SERVO,V(vpin),OPCODE_PAD,V(position),OPCODE_PAD,V(profile),OPCODE_PAD,V(duration)
+        IODevice::writeAnalogue(operand,GET_OPERAND(1),GET_OPERAND(2),GET_OPERAND(3));          
+        break;
+       
+       case OPCODE_WAITFOR: // OPCODE_SERVO,V(pin)
+            if (IODevice::isBusy(operand)) {
+              delayMe(100);
+              return;
+            }
+            break;
+
+       case OPCODE_PRINT:
+            printMessage(operand);
+            break;
+               
+       case OPCODE_ROUTE:
+       case OPCODE_AUTOMATION:
+       case OPCODE_SEQUENCE:
+          if (diag) DIAG(F("EXRAIL begin(%d)"),operand);
+          break;
+
+       case OPCODE_PAD: // Just a padding for previous opcode needing >1 operad byte.
+       case OPCODE_SIGNAL: // Signal definition ignore at run time
+       case OPCODE_TURNOUT: // Turnout definition ignored at runtime
+       case OPCODE_SERVOTURNOUT: // Turnout definition ignored at runtime
+       case OPCODE_PINTURNOUT: // Turnout definition ignored at runtime
+       case OPCODE_ONCLOSE: // Turnout event catcers ignored here
+       case OPCODE_ONTHROW: // Turnout definition ignored at runtime
+       break;
+    
+    default:
+      kill(F("INVOP"),operand);
+    }
+    // Falling out of the switch means move on to the next opcode
+    SKIPOP;
+}
+
+void RMFT2::delayMe(long delay) {
+     delayTime=delay;
+     delayStart=millis();
+}
+
+void RMFT2::setFlag(VPIN id,byte onMask, byte offMask) {  
+   if (FLAGOVERFLOW(id)) return; // Outside range limit
+   byte f=flags[id];
+   f &= ~offMask;
+   f |= onMask;
+   flags[id]=f;
+}
+
+bool RMFT2::getFlag(VPIN id,byte mask) {
+   if (FLAGOVERFLOW(id)) return 0; // Outside range limit
+   return flags[id]&mask;   
+}
+
+void RMFT2::kill(const FSH * reason, int operand) {
+     if (reason) DIAG(F("EXRAIL ERROR pc=%d, cab=%d, %S %d"), progCounter,loco, reason, operand);
+     else if (diag) DIAG(F("ENDTASK at pc=%d"), progCounter); 
+     delete this;
+}
+
+/* static */ void RMFT2::doSignal(VPIN id,bool red, bool amber, bool green) { 
+  // CAUTION: hides class member progCounter
+  for (int progCounter=0;; SKIPOP){
+     byte opcode=GET_OPCODE;
+     if (opcode==OPCODE_ENDEXRAIL) return;
+     if (opcode!=OPCODE_SIGNAL) continue;
+     byte redpin=GET_OPERAND(0);
+     if (redpin!=id)continue;
+     byte amberpin=GET_OPERAND(1);
+     byte greenpin=GET_OPERAND(2);
+     // If amberpin is zero, synthesise amber from red+green
+     IODevice::write(redpin,red || (amber && (amberpin==0)));
+     if (amberpin) IODevice::write(amberpin,amber);
+     if (greenpin) IODevice::write(greenpin,green || (amber && (amberpin==0)));
+     return;
+   }
+  } 
+ void RMFT2::turnoutEvent(int16_t turnoutId, bool closed) {
+    
+    // Check we dont already have a task running this turnout
+    RMFT2 * task=loopTask;                 
+    while(task) {
+      if (task->onTurnoutId==turnoutId) {
+        DIAG(F("Recursive ONTHROW/ONCLOSE for Turnout %d"),turnoutId);
+        return;
+        }
+      task=task->next;      
+      if (task==loopTask) break;      
+      }
+    // Hunt for an ONTHROW/ONCLOSE for this turnout   
+    byte huntFor=closed ?  OPCODE_ONCLOSE : OPCODE_ONTHROW ;
+    // caution hides class progCounter;
+    for (int progCounter=0;; SKIPOP){
+     byte opcode=GET_OPCODE;
+     if (opcode==OPCODE_ENDEXRAIL) return;
+     if (opcode!=huntFor) continue;
+     if (turnoutId!=(int16_t)GET_OPERAND(0)) continue;
+     task=new RMFT2(progCounter);  // new task starts at this instruction
+     task->onTurnoutId=turnoutId; // flag for recursion detector
+     return;
+   }
+ }
+ 
+ void RMFT2::printMessage2(const FSH * msg) {
+        DIAG(F("EXRAIL(%d) %S"),loco,msg);
+   }
+
+// This is called by emitRouteDescriptions to emit a withrottle description for a route or autoomation. 
+void RMFT2::emitRouteDescription(Print * stream, char type, int id, const FSH * description) {
+ StringFormatter::send(stream,F("]\\[%c%d}|{%S}|{%c"),
+              type,id,description, type=='R'?'2':'4');
+}
+ 

RMFT2.h

@@ -0,0 +1,117 @@
+/*
+ *  © 2020, Chris Harlow. All rights reserved.
+ *  
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#ifndef RMFT2_H
+#define RMFT2_H
+#include "FSH.h"
+#include "IODevice.h"
+   
+// The following are the operation codes (or instructions) for a kind of virtual machine.
+// Each instruction is normally 2 bytes long with an operation code followed by a parameter.
+// In cases where more than one parameter is required, the first parameter is followed by one  
+// or more OPCODE_PAD instructions with the subsequent parameters. This wastes a byte but makes 
+// searching easier as a parameter can never be confused with an opcode. 
+// 
+enum OPCODE : byte {OPCODE_THROW,OPCODE_CLOSE,
+             OPCODE_FWD,OPCODE_REV,OPCODE_SPEED,OPCODE_INVERT_DIRECTION,
+             OPCODE_RESERVE,OPCODE_FREE,
+             OPCODE_AT,OPCODE_AFTER,
+             OPCODE_LATCH,OPCODE_UNLATCH,OPCODE_SET,OPCODE_RESET,
+             OPCODE_IF,OPCODE_IFNOT,OPCODE_ENDIF,OPCODE_IFRANDOM,OPCODE_IFRESERVE,
+             OPCODE_DELAY,OPCODE_DELAYMINS,OPCODE_RANDWAIT,
+             OPCODE_FON,OPCODE_FOFF,OPCODE_XFON,OPCODE_XFOFF,
+             OPCODE_RED,OPCODE_GREEN,OPCODE_AMBER,
+             OPCODE_SERVO,OPCODE_SIGNAL,OPCODE_TURNOUT,OPCODE_WAITFOR,
+             OPCODE_PAD,OPCODE_FOLLOW,OPCODE_CALL,OPCODE_RETURN,
+             OPCODE_JOIN,OPCODE_UNJOIN,OPCODE_READ_LOCO1,OPCODE_READ_LOCO2,OPCODE_POM,
+             OPCODE_START,OPCODE_SETLOCO,OPCODE_SENDLOCO,
+             OPCODE_PAUSE, OPCODE_RESUME,OPCODE_POWEROFF,
+             OPCODE_ONCLOSE, OPCODE_ONTHROW, OPCODE_SERVOTURNOUT, OPCODE_PINTURNOUT,
+             OPCODE_PRINT,
+             OPCODE_ROUTE,OPCODE_AUTOMATION,OPCODE_SEQUENCE,OPCODE_ENDTASK,OPCODE_ENDEXRAIL
+             };
+
+
+ 
+  // Flag bits for status of hardware and TPL
+  static const byte SECTION_FLAG = 0x01;
+  static const byte LATCH_FLAG = 0x02;
+  static const byte TASK_FLAG = 0x04;
+
+  static const byte  MAX_STACK_DEPTH=4;
+ 
+   static const short MAX_FLAGS=256;
+  #define FLAGOVERFLOW(x) x>=MAX_FLAGS
+
+ class RMFT2 {
+   public:
+    static void begin();
+    static void loop();
+    RMFT2(int progCounter);
+    RMFT2(int route, uint16_t cab);
+    ~RMFT2();
+    static void readLocoCallback(int16_t cv);
+    static void emitWithrottleRouteList(Print* stream); 
+    static void createNewTask(int route, uint16_t cab);
+    static void turnoutEvent(int16_t id, bool closed);  
+private: 
+    static void ComandFilter(Print * stream, byte & opcode, byte & paramCount, int16_t p[]);
+    static bool parseSlash(Print * stream, byte & paramCount, int16_t p[]) ;
+    static void streamFlags(Print* stream);
+    static void setFlag(VPIN id,byte onMask, byte OffMask=0);
+    static bool getFlag(VPIN id,byte mask);   
+    static int locateRouteStart(int16_t _route);
+    static int16_t progtrackLocoId;
+    static void doSignal(VPIN id,bool red, bool amber, bool green); 
+    static void emitRouteDescription(Print * stream, char type, int id, const FSH * description);
+    static void emitWithrottleDescriptions(Print * stream);
+    
+    static RMFT2 * loopTask;
+    static RMFT2 * pausingTask;
+    void delayMe(long millisecs);
+    void driveLoco(byte speedo);
+    bool readSensor(uint16_t sensorId);
+    bool skipIfBlock();
+    bool readLoco();
+    void loop2();
+    void kill(const FSH * reason=NULL,int operand=0);          
+    void printMessage(uint16_t id);  // Built by RMFTMacros.h
+    void printMessage2(const FSH * msg);
+
+    
+   static bool diag;
+   static const  FLASH  byte RouteCode[];
+   static byte flags[MAX_FLAGS];
+ 
+  // Local variables - exist for each instance/task 
+    RMFT2 *next;   // loop chain 
+    int progCounter;    // Byte offset of next route opcode in ROUTES table
+    unsigned long delayStart; // Used by opcodes that must be recalled before completing
+    unsigned long waitAfter; // Used by OPCODE_AFTER
+    unsigned long  delayTime;
+    byte  taskId;
+    
+    uint16_t loco;
+    bool forward;
+    bool invert;
+    byte speedo;
+    int16_t onTurnoutId;
+    byte stackDepth;
+    int callStack[MAX_STACK_DEPTH];
+};
+#endif

RMFTMacros.h

@@ -0,0 +1,311 @@
+/*
+ *  © 2020,2021 Chris Harlow. All rights reserved.
+ *  
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+#ifndef RMFTMacros_H
+#define RMFTMacros_H
+
+// remove normal code LCD & SERIAL macros (will be restored later)
+#undef LCD
+#undef SERIAL
+
+
+// This file will include and build the EXRAIL script and associated helper tricks.
+// It does this by incliding myAutomation.h several times, each with a set of macros to 
+// extract the relevant parts.
+
+// The entire automation script is contained within a byte array RMFT2::RouteCode[]
+// made up of opcode and parameter pairs.
+// ech opcode is a 1 byte operation plus 2 byte operand. 
+// The array is normally built using the macros below as this makes it easier 
+// to manage the cases where:
+// - padding must be applied to ensure the correct alignment of the next instruction
+// - large parameters must be split up
+// - multiple parameters aligned correctly
+// - a single macro requires multiple operations
+
+// Descriptive texts for routes and animations are created in a sepaerate function which
+// can be called to emit a list of routes/automatuions in a form suitable for Withrottle. 
+ 
+// PRINT(msg) and LCD(row,msg) is implemented in a separate pass to create 
+// a getMessageText(id) function.  
+
+// CAUTION: The macros below are multiple passed over myAutomation.h
+
+// Pass 1 Implements aliases and 
+// converts descriptions to  withrottle format emitter function
+// Most macros are simply ignored in this pass.
+
+
+#define ALIAS(name,value) const int name=value; 
+#define EXRAIL  void  RMFT2::emitWithrottleDescriptions(Print * stream) {(void)stream;
+#define ROUTE(id, description) emitRouteDescription(stream,'R',id,F(description));
+#define AUTOMATION(id, description) emitRouteDescription(stream,'A',id,F(description));
+#define ENDEXRAIL  }
+ 
+#define AFTER(sensor_id)
+#define AMBER(signal_id)
+#define AT(sensor_id)
+#define CALL(route) 
+#define CLOSE(id) 
+#define DELAY(mindelay)
+#define DELAYMINS(mindelay)
+#define DELAYRANDOM(mindelay,maxdelay) 
+#define DONE
+#define ENDIF  
+#define ENDTASK
+#define ESTOP 
+#define FADE(pin,value,ms)
+#define FOFF(func)
+#define FOLLOW(route) 
+#define FON(func) 
+#define FREE(blockid) 
+#define FWD(speed) 
+#define GREEN(signal_id)
+#define IF(sensor_id) 
+#define IFNOT(sensor_id)
+#define IFRANDOM(percent) 
+#define IFRESERVE(block)
+#define INVERT_DIRECTION 
+#define JOIN 
+#define LATCH(sensor_id) 
+#define LCD(row,msg) 
+#define LCN(msg) 
+#define ONCLOSE(turnout_id)
+#define ONTHROW(turnout_id) 
+#define PAUSE
+#define PRINT(msg) 
+#define POM(cv,value)
+#define POWEROFF
+#define READ_LOCO 
+#define RED(signal_id) 
+#define RESERVE(blockid) 
+#define RESET(pin) 
+#define RESUME 
+#define RETURN 
+#define REV(speed) 
+#define START(route) 
+#define SENDLOCO(cab,route) 
+#define SERIAL(msg) 
+#define SERIAL1(msg) 
+#define SERIAL2(msg) 
+#define SERIAL3(msg) 
+#define SERVO(id,position,profile) 
+#define SERVO2(id,position,duration) 
+#define SETLOCO(loco) 
+#define SET(pin) 
+#define SEQUENCE(id) 
+#define SPEED(speed) 
+#define STOP 
+#undef SIGNAL
+#define SIGNAL(redpin,amberpin,greenpin) 
+#define SERVO_TURNOUT(id,pin,activeAngle,inactiveAngle,profile) 
+#define PIN_TURNOUT(id,pin) 
+#define THROW(id)  
+#define TURNOUT(id,addr,subaddr) 
+#define UNJOIN 
+#define UNLATCH(sensor_id) 
+#define WAITFOR(pin)
+#define XFOFF(cab,func)
+#define XFON(cab,func)
+
+#include "myAutomation.h"
+
+// setup for pass 2... Create getMessageText function
+#undef ALIAS
+#undef ROUTE
+#undef AUTOMATION  
+#define ROUTE(id, description)
+#define AUTOMATION(id, description)  
+
+#undef EXRAIL 
+#undef PRINT
+#undef LCN
+#undef SERIAL
+#undef SERIAL1
+#undef SERIAL2
+#undef SERIAL3
+#undef ENDEXRAIL  
+#undef LCD
+const int StringMacroTracker1=__COUNTER__;
+#define ALIAS(name,value) 
+#define EXRAIL void  RMFT2::printMessage(uint16_t id) { switch(id) {
+#define ENDEXRAIL  default: DIAG(F("printMessage error %d %d"),id,StringMacroTracker1); return ; }}
+#define PRINT(msg)    case (__COUNTER__ - StringMacroTracker1) : printMessage2(F(msg));break;
+#define LCN(msg)      case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&LCN_SERIAL,F(msg));break;
+#define SERIAL(msg)   case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&Serial,F(msg));break;
+#define SERIAL1(msg)  case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&Serial1,F(msg));break;
+#define SERIAL2(msg)  case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&Serial2,F(msg));break;
+#define SERIAL3(msg)  case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&Serial3,F(msg));break;
+#define LCD(id,msg)   case (__COUNTER__ - StringMacroTracker1) : StringFormatter::lcd(id,F(msg));break;
+#include "myAutomation.h"
+
+// Setup for Pass 3: create main routes table 
+#undef AFTER
+#undef AMBER
+#undef AT
+#undef AUTOMATION 
+#undef CALL
+#undef CLOSE
+#undef DELAY
+#undef DELAYMINS
+#undef DELAYRANDOM
+#undef DONE
+#undef ENDIF
+#undef ENDEXRAIL
+#undef ENDTASK
+#undef ESTOP
+#undef EXRAIL
+#undef FOFF
+#undef FOLLOW
+#undef FON
+#undef FREE
+#undef FWD
+#undef GREEN
+#undef IF
+#undef IFNOT
+#undef IFRANDOM
+#undef IFRESERVE
+#undef INVERT_DIRECTION
+#undef JOIN
+#undef LATCH
+#undef LCD
+#undef LCN
+#undef ONCLOSE
+#undef ONTHROW
+#undef PAUSE
+#undef POM
+#undef POWEROFF
+#undef PRINT
+#undef READ_LOCO
+#undef RED
+#undef RESERVE
+#undef RESET
+#undef RESUME
+#undef RETURN
+#undef REV
+#undef ROUTE 
+#undef START
+#undef SEQUENCE 
+#undef SERVO
+#undef SERVO2
+#undef FADE
+#undef SENDLOCO
+#undef SERIAL
+#undef SERIAL1
+#undef SERIAL2
+#undef SERIAL3
+#undef SETLOCO
+#undef SET
+#undef SPEED
+#undef STOP
+#undef SIGNAL
+#undef SERVO_TURNOUT
+#undef PIN_TURNOUT
+#undef THROW
+#undef TURNOUT
+#undef UNJOIN
+#undef UNLATCH
+#undef WAITFOR
+#undef XFOFF
+#undef XFON
+
+// Define macros for route code creation 
+#define V(val) ((int16_t)(val))&0x00FF,((int16_t)(val)>>8)&0x00FF
+#define NOOPERAND 0,0
+
+#define ALIAS(name,value) 
+#define EXRAIL const  FLASH  byte RMFT2::RouteCode[] = {
+#define AUTOMATION(id, description)  OPCODE_AUTOMATION, V(id), 
+#define ROUTE(id, description)  OPCODE_ROUTE, V(id), 
+#define SEQUENCE(id)  OPCODE_SEQUENCE, V(id), 
+#define ENDTASK OPCODE_ENDTASK,NOOPERAND,
+#define DONE OPCODE_ENDTASK,NOOPERAND,
+#define ENDEXRAIL OPCODE_ENDTASK,NOOPERAND,OPCODE_ENDEXRAIL,NOOPERAND };
+ 
+#define AFTER(sensor_id) OPCODE_AT,V(sensor_id),OPCODE_AFTER,V(sensor_id),
+#define AMBER(signal_id) OPCODE_AMBER,V(signal_id),
+#define AT(sensor_id) OPCODE_AT,V(sensor_id),
+#define CALL(route) OPCODE_CALL,V(route),
+#define CLOSE(id)  OPCODE_CLOSE,V(id),
+#define DELAY(ms) OPCODE_DELAY,V(ms/100L),
+#define DELAYMINS(mindelay) OPCODE_DELAYMINS,V(mindelay),
+#define DELAYRANDOM(mindelay,maxdelay) OPCODE_DELAY,V(mindelay/100L),OPCODE_RANDWAIT,V((maxdelay-mindelay)/100L),
+#define ENDIF  OPCODE_ENDIF,NOOPERAND,
+#define ESTOP OPCODE_SPEED,V(1), 
+#define FADE(pin,value,ms) OPCODE_SERVO,V(pin),OPCODE_PAD,V(value),OPCODE_PAD,V(PCA9685::ProfileType::UseDuration|PCA9685::NoPowerOff),OPCODE_PAD,V(ms/100L),
+#define FOFF(func) OPCODE_FOFF,V(func),
+#define FOLLOW(route) OPCODE_FOLLOW,V(route),
+#define FON(func) OPCODE_FON,V(func),
+#define FREE(blockid) OPCODE_FREE,V(blockid),
+#define FWD(speed) OPCODE_FWD,V(speed),
+#define GREEN(signal_id) OPCODE_GREEN,V(signal_id),
+#define IF(sensor_id) OPCODE_IF,V(sensor_id),
+#define IFNOT(sensor_id) OPCODE_IFNOT,V(sensor_id),
+#define IFRANDOM(percent) OPCODE_IFRANDOM,V(percent),
+#define IFRESERVE(block) OPCODE_IFRESERVE,V(block),
+#define INVERT_DIRECTION OPCODE_INVERT_DIRECTION,NOOPERAND,
+#define JOIN OPCODE_JOIN,NOOPERAND,
+#define LATCH(sensor_id) OPCODE_LATCH,V(sensor_id),
+#define LCD(id,msg) PRINT(msg)
+#define LCN(msg) PRINT(msg)
+#define ONCLOSE(turnout_id) OPCODE_ONCLOSE,V(turnout_id),
+#define ONTHROW(turnout_id) OPCODE_ONTHROW,V(turnout_id),
+#define PAUSE OPCODE_PAUSE,NOOPERAND,
+#define POM(cv,value) OPCODE_POM,V(cv),OPCODE_PAD,V(value),
+#define POWEROFF OPCODE_POWEROFF,NOOPERAND,
+#define PRINT(msg) OPCODE_PRINT,V(__COUNTER__ - StringMacroTracker2),
+#define READ_LOCO OPCODE_READ_LOCO1,NOOPERAND,OPCODE_READ_LOCO2,NOOPERAND,
+#define RED(signal_id) OPCODE_RED,V(signal_id),
+#define RESERVE(blockid) OPCODE_RESERVE,V(blockid),
+#define RESET(pin) OPCODE_RESET,V(pin),
+#define RESUME OPCODE_RESUME,NOOPERAND,
+#define RETURN OPCODE_RETURN,NOOPERAND,
+#define REV(speed) OPCODE_REV,V(speed),
+#define SENDLOCO(cab,route) OPCODE_SENDLOCO,V(cab),OPCODE_PAD,V(route),
+#define SERIAL(msg) PRINT(msg)
+#define SERIAL1(msg) PRINT(msg)
+#define SERIAL2(msg) PRINT(msg)
+#define SERIAL3(msg) PRINT(msg)
+#define START(route) OPCODE_START,V(route),
+#define SERVO(id,position,profile) OPCODE_SERVO,V(id),OPCODE_PAD,V(position),OPCODE_PAD,V(PCA9685::profile),OPCODE_PAD,V(0),
+#define SERVO2(id,position,ms) OPCODE_SERVO,V(id),OPCODE_PAD,V(position),OPCODE_PAD,V(PCA9685::Instant),OPCODE_PAD,V(ms/100L),
+#define SETLOCO(loco) OPCODE_SETLOCO,V(loco),
+#define SET(pin) OPCODE_SET,V(pin),
+#define SPEED(speed) OPCODE_SPEED,V(speed),
+#define STOP OPCODE_SPEED,V(0), 
+#define SIGNAL(redpin,amberpin,greenpin) OPCODE_SIGNAL,V(redpin),OPCODE_PAD,V(amberpin),OPCODE_PAD,V(greenpin), 
+#define SERVO_TURNOUT(id,pin,activeAngle,inactiveAngle,profile) OPCODE_SERVOTURNOUT,V(id),OPCODE_PAD,V(pin),OPCODE_PAD,V(activeAngle),OPCODE_PAD,V(inactiveAngle),OPCODE_PAD,V(PCA9685::ProfileType::profile),
+#define PIN_TURNOUT(id,pin) OPCODE_PINTURNOUT,V(id),OPCODE_PAD,V(pin), 
+#define THROW(id)  OPCODE_THROW,V(id),
+#define TURNOUT(id,addr,subaddr) OPCODE_TURNOUT,V(id),OPCODE_PAD,V(addr),OPCODE_PAD,V(subaddr),
+#define UNJOIN OPCODE_UNJOIN,NOOPERAND,
+#define UNLATCH(sensor_id) OPCODE_UNLATCH,V(sensor_id),
+#define WAITFOR(pin) OPCODE_WAITFOR,V(pin),
+#define XFOFF(cab,func) OPCODE_XFOFF,V(cab),OPCODE_PAD,V(func),
+#define XFON(cab,func) OPCODE_XFON,V(cab),OPCODE_PAD,V(func),
+
+// PASS2 Build RouteCode
+const int StringMacroTracker2=__COUNTER__;
+#include "myAutomation.h"
+
+// Restore normal code LCD & SERIAL  macro
+#undef LCD
+#define LCD   StringFormatter::lcd
+#undef SERIAL
+#define SERIAL  0x0
+#endif

Release - Architecture Doc/Prod-Release-Notes.md

@@ -0,0 +1,93 @@
+The DCC-EX Team is pleased to release CommandStation-EX-v3.0.0 as a Production Release.  This release is a major re-write of earlier versions.  We've re-architected the code-base so that it can better handle new features going forward.  
+
+**Known Bugs:**
+ - **Consisting through JMRI** - currently does not work in this release.  You may use the <M> command to do this manually.
+ - **Wi-Fi** - works, but can be challenging to use if you want to switch between AP mode and STA station mode.
+ - **Pololu Motor Shield** - is supported with this release, but the user may have to play around with some timings to enable programming mode due to limitation in its current sensing circuitry 
+ 
+**Summary of the key new features added to CommandStation-EX V3.0.3**
+ - **<W addr> command to write loco address and clear consist** 
+ - **<R> command will allow for consist address**
+ - **Startup commands implemented**
+ 
+**Summary of the key new features added to CommandStation-EX V3.0.2:**
+- **Create new output for current in mA for ``<c>`` command** - New current response outputs current in mA, overlimit current, and maximum board capable current
+- **Simultaneously update JMRI to handle new current meter**
+
+**Summary of the key new features added to CommandStation-EX V3.0.1:**
+ - **Add back fix for jitter**
+ - **Add Turnouts, Outputs and Sensors to ```<s>``` command output**
+
+ **Summary of the key new features added to CommandStation-EX V3.0.0:**
+
+ - **New USB Browser Based Throttle** - WebThrottle-EX is a full front-end to controller to control the CS to run trains.
+ - **WiFi Support** - AP and station modes supported. Auto-detection of an ESP8266 WiFi module with AT firmware on a Mega's serial port. Connection to JMRI and WiThrottle clients.
+ - **Withrottle Integrations** - Act as a host for up to four WiThrottle clients concurrently. 
+ - **Add LCD/OLED support** - OLED supported on Mega only
+ - **Improved CV programming routines** - checks for length of CV pulse, and breaks out of the wait state once it has received an ACK, now reading one CV per second.
+ - **Improved current sensing** - rewrote current sensing routines for safer operation. Current thresholds based on milliamps, not magic numbers
+ - **Individual track power control** - Ability to toggle power on either or both tracks, and to "JOIN" the tracks and make them output the same waveform for multiple power districts.
+ - **Single or Dual-Pin PWM output** - Allows control of H-bridges with PH/EN or dual PWM inputs
+ - **New, simpler function command** - ```<F>``` command allows setting functions based on their number, not based on a code as in ```<f>```
+ - **Function reminders** - Function reminders are sent in addition to speed reminders
+ - **Functions to F28** - All NMRA functions are now supported
+ - **Filters and user functions** - Ability to filter commands in the parser and execute custom code based on them. (ex: Redirect Turnout commands via NRF24)
+ - **Diagnostic ```<D>``` commands** - See documentation for a full list of new diagnostic commands
+ - **Rewrote DCC++ Parser** - more efficient operation, accepts multi-char input and uses less RAM
+ - **Rewritten waveform generator** - capable of using any pin for DCC waveform out, eliminating the need for jumpers
+ - **Rewritten packet generator** - Simplify and make smaller, remove idea of "registers" from original code
+ - **Add free RAM messages** - Free RAM messages are now printed whenever there is a decerase in available RAM
+ - **Fix EEPROM bugs**
+ - **Number of locos discovery command** - ```<#>``` command 
+ - **Support for more locomotives** - 20 locomotives on an UNO and 50 an a Mega.
+ - **Automatic slot managment** - slot variable in throttle/function commands are ignored and slot management is taken care of automatically. ```<!>``` command added to release locos from memory.
+
+
+**Key Contributors**
+
+**Project Lead**
+- Fred Decker - Holly Springs, North Carolina, USA (FlightRisk)
+
+**CommandStation-EX Developers**
+- Chris Harlow - Bournemouth, UK (UKBloke)
+- Harald Barth - Stockholm, Sweden (Haba)
+- Fred Decker - Holly Springs, North Carolina, USA (FlightRisk)
+- Dave Cutting - Logan, Utah, USA (Dave Cutting/ David Cutting)
+- M Steve Todd - - Engine Driver and JMRI Interface
+- Scott Catalanno - Pennsylvania
+- Gregor Baues - Île-de-France, France (grbba)
+
+**exInstaller Software**
+- Anthony W - Dayton, Ohio, USA (Dex, Dex++)
+
+**Website and Documentation**
+- Mani Kumar - Bangalor, India (Mani / Mani Kumar)
+- Fred Decker - Holly Springs, North Carolina, USA (FlightRisk)
+- Dave Cutting - Logan, Utah, USA (Dave Cutting/ David Cutting)
+- Roger Beschizza - Dorset, UK (Roger Beschizza)
+- Keith Ledbetter - Chicago, Illinois, USA (Keith Ledbetter)
+- Kevin Smith - (KCSmith)
+
+**WebThrotle-EX**
+- Fred Decker - Holly Springs, NC (FlightRisk/FrightRisk)
+- Mani Kumar - Bangalor, India (Mani /Mani Kumar)
+- Matt H - 
+
+
+
+**Beta Testing / Release Management / Support**
+- Larry Dribin	- Release Management
+- Keith Ledbetter	
+- BradVan der Elst	
+- Andrew Pye	
+- Mike Bowers	
+- Randy McKenzie
+- Roberto Bravin
+- Sim Brigden
+- Alan Lautenslager
+- Martin Bafver	
+- Mário André Silva	
+- Anthony Kochevar	
+- Gajanatha Kobbekaduwe	
+- Sumner Patterson 
+- Paul - Virginia, USA

Release - Architecture Doc/Rough Release-Notes.md

@@ -0,0 +1,23 @@
+# CommandStation-EX Release Notes
+
+## v3.0.0
+
+ - **WiFi Support** - AP and station modes supported. Auto-detection of an ESP8266 WiFi module with AT firmware on a Mega's serial port. Connection to JMRI and WiThrottle clients.
+ - **Withrottle Integrations** - Act as a host for four WiThrottle clients concurrently. 
+ - **Add LCD/OLED support** - OLED supported on Mega only
+ - **Improved CV programming routines** - checks for length of CV pulse, and breaks out of the wait state once it has received an ACK, now reading one CV per second.
+ - **Improved current sensing** - rewrote current sensing routines for safer operation. Current thresholds based on milliamps, not magic numbers
+ - **Individual track power control** - Ability to toggle power on either or both tracks, and to "JOIN" the tracks and make them output the same waveform for multiple power districts.
+ - **Single or Dual-Pin PWM output** - Allows control of H-bridges with PH/EN or dual PWM inputs
+ - **New, simpler function command** - ```<F>``` command allows setting functions based on their number, not based on a code as in ```<f>```
+ - **Function reminders** - Function reminders are sent in addition to speed reminders
+ - **Functions to F28** - All NMRA functions are now supported
+ - **Filters and user functions** - Ability to filter commands in the parser and execute custom code based on them
+ - **Diagnostic ```<D>``` commands** - See documentation for a full list of new diagnostic commands
+ - **Rewrote DCC++ Parser** - more efficient operation, accepts multi-char input and uses less RAM
+ - **Rewritten waveform generator** - capable of using any pin for DCC waveform out, eliminating the need for jumpers
+ - **Rewritten packet generator** - Simplify and make smaller, remove idea of "registers" from original code
+ - **Add free RAM messages** - Free RAM messages are now printed whenever there is a decerase in available RAM
+ - **Fix EEPROM bugs**
+ - **Support for more decoders** - Support for 20 (Uno) or 50 (Mega) mobile decoders, number automaticlaly recognized by JMRI.
+ - **Automatic slot managment** - slot variable in throttle/function commands are ignored and slot management is taken care of automatically. ```<!>``` command added to release locos from memory.

Release_Notes/release_notes_v3.0.0.md

@@ -0,0 +1,85 @@
+
+
+The DCC-EX Team is pleased to release CommandStation-EX-v3.0.0 as a Production Release.  This release is a major re-write of earlier versions.  We've re-architected the code-base so that it can better handle new features going forward.  Download the compressed files here:
+
+**Downloads (zip and tar.gz) below. These are named without version number in the folder name to make the Arduino IDE happy.**
+
+[CommandStation-EX.zip](https://github.com/DCC-EX/CommandStation-EX/files/5611333/CommandStation-EX.zip)
+[CommandStation-EX.tar.gz](https://github.com/DCC-EX/CommandStation-EX/files/5611335/CommandStation-EX.tar.gz)
+
+
+**Known Bugs:**
+ - **Consisting through JMRI** - currently does not work in this release.  A number of testers were able to develop a work around.  If interested enter a Support Ticket.
+ - **Wi-Fi** - works, but can be challenging to use if you want to switch between AP mode and STA station mode.
+ - **Pololu Motor Shield** - is supported with this release, but the user may have to play around with some timings to enable programming mode due to limitation in its current sensing circuitry 
+
+ **Summary of the key new features added to CommandStation-EX V3.0.0:**
+ - **WiFi Support** - AP and station modes supported. Auto-detection of an ESP8266 WiFi module with AT firmware on a Mega's serial port. Connection to JMRI and WiThrottle clients.
+ - **Withrottle Integrations** - Act as a host for four WiThrottle clients concurrently. 
+ - **Add LCD/OLED support** - OLED supported on Mega only
+ - **Improved CV programming routines** - checks for length of CV pulse, and breaks out of the wait state once it has received an ACK, now reading one CV per second.
+ - **Improved current sensing** - rewrote current sensing routines for safer operation. Current thresholds based on milliamps, not magic numbers
+ - **Individual track power control** - Ability to toggle power on either or both tracks, and to "JOIN" the tracks and make them output the same waveform for multiple power districts.
+ - **Single or Dual-Pin PWM output** - Allows control of H-bridges with PH/EN or dual PWM inputs
+ - **New, simpler function command** - ```<F>``` command allows setting functions based on their number, not based on a code as in ```<f>```
+ - **Function reminders** - Function reminders are sent in addition to speed reminders
+ - **Functions to F28** - All NMRA functions are now supported
+ - **Filters and user functions** - Ability to filter commands in the parser and execute custom code based on them
+ - **Diagnostic ```<D>``` commands** - See documentation for a full list of new diagnostic commands
+ - **Rewrote DCC++ Parser** - more efficient operation, accepts multi-char input and uses less RAM
+ - **Rewritten waveform generator** - capable of using any pin for DCC waveform out, eliminating the need for jumpers
+ - **Rewritten packet generator** - Simplify and make smaller, remove idea of "registers" from original code
+ - **Add free RAM messages** - Free RAM messages are now printed whenever there is a decerase in available RAM
+ - **Fix EEPROM bugs**
+ - **Number of locos discovery command** - ```<#>``` command 
+ - **Support for more locomotives** - 20 locomotives on an UNO and 50 an a Mega.
+ - **Automatic slot managment** - slot variable in throttle/function commands are ignored and slot management is taken care of automatically. ```<!>``` command added to release locos from memory.
+
+
+**Key Contributors**
+
+**Project Lead**
+- Fred Decker - Holly Springs, North Carolina, USA (FlightRisk)
+
+**CommandStation-EX Developers**
+- Chris Harlow - Bournemouth, UK (UKBloke)
+- Harald Barth - Stockholm, Sweden (Haba)
+- Fred Decker - Holly Springs, North Carolina, USA (FlightRisk)
+- Dave Cutting - Logan, Utah, USA (Dave Cutting/ David Cutting)
+- M Steve Todd - - Engine Driver and JMRI Interface
+- Scott Catalanno - Pennsylvania
+- Gregor Baues - Île-de-France, France (grbba)
+
+**exInstaller Software**
+- Anthony W - Dayton, Ohio, USA (Dex, Dex++)
+
+**Website and Documentation**
+- Mani Kumar - Bangalor, India (Mani / Mani Kumar)
+- Fred Decker - Holly Springs, North Carolina, USA (FlightRisk)
+- Dave Cutting - Logan, Utah, USA (Dave Cutting/ David Cutting)
+- Roger Beschizza - Dorset, UK (Roger Beschizza)
+- Keith Ledbetter - Chicago, Illinois, USA (Keith Ledbetter)
+-Kevin Smith - (KCSmith)
+
+**Beta Testing / Release Management / Support**
+- Larry Dribin	- Release Management
+- Keith Ledbetter	
+- BradVan der Elst	
+- Andrew Pye	
+- Mike Bowers	
+- Randy McKenzie
+- Roberto Bravin
+- Sim Brigden
+- Alan Lautenslager
+- Martin Bafver	
+- Mário André Silva	
+- Anthony Kochevar	
+- Gajanatha Kobbekaduwe	
+- Sumner Patterson 
+- Paul - Virginia, USA
+
+**Downloads (zip and tar.gz) below. These are named without version number in the folder name to make the Arduino IDE happy.**
+
+[CommandStation-EX.zip](https://github.com/DCC-EX/CommandStation-EX/files/5611333/CommandStation-EX.zip)
+[CommandStation-EX.tar.gz](https://github.com/DCC-EX/CommandStation-EX/files/5611335/CommandStation-EX.tar.gz)
+

Release_Notes/release_notes_v3.1.0.md

@@ -0,0 +1,206 @@
+The DCC-EX Team is pleased to release CommandStation-EX-v3.1.0 as a Production Release.  Release v3.1.0 is a minor release that adds additional features and fixes a number of bugs. With the number of new features, this could have easily been a major release. The team is continually improving the architecture of DCC++EX to make it more flexible and optimizing the code so as to get more performance from the Arduino (and other) microprocessors.  This release includes all of the Point Releases from v3.0.1 to v3.0.16.
+
+**Downloads (zip and tar.gz) below. These are named without version number in the folder name to make the Arduino IDE happy.**
+
+[CommandStation-EX.zip](https://github.com/DCC-EX/CommandStation-EX/releases/download/v3.1.0-Prod/CommandStation-EX.zip)
+[CommandStation-EX.tar.gz](https://github.com/DCC-EX/CommandStation-EX/releases/download/v3.1.0-Prod/CommandStation-EX.tar.gz)
+
+**Known Issues**
+
+- **Wi-Fi** - works, but requires sending <AT> commands from a serial monitor if you want to switch between AP mode and STA station mode after initial setup
+- **Pololu Motor Shield** - is supported with this release, but the user may have to adjust timings to enable programming mode due to limitation in its current sensing circuitry
+
+#### Summary of key features and/or bug fixes by Point Release
+
+**Summary of the key new features added to CommandStation-EX V3.0.16**
+
+- Ignore CV1 bit 7 read if rejected by a non NMRA compliant decoder when identifying loco id
+
+**Summary of the key new features added to CommandStation-EX V3.0.15**
+
+- Send function commands just once instead of repeating them 4 times
+
+**Summary of the key new features added to CommandStation-EX V3.0.14**
+
+- Add feature to tolerate decoders that incorrectly have gaps in their ACK pulse
+- Provide proper track power management when joining and unjoining tracks with <1 JOIN>
+
+**Summary of the key new features added to CommandStation-EX V3.0.13**
+
+- Fix for CAB Functions greater than 127
+
+**Summary of the key new features added to CommandStation-EX V3.0.12**
+
+- Fixed clear screen issue for nanoEvery and nanoWifi
+
+**Summary of the key new features added to CommandStation-EX V3.0.11**
+
+- Reorganized files for support of 128 speed steps
+
+**Summary of the key new features added to CommandStation-EX V3.0.10**
+
+- Added Support for the Teensy 3.2, 3.5, 3.6, 4.0 and 4.1 MCUs
+- No functional change just changes to avoid complier warnings for Teensy/nanoEvery
+
+**Summary of the key new features added to CommandStation-EX V3.0.9**
+
+- Rearranges serial newlines for the benefit of JMRI
+- Major update for efficiencies in displays (LCD, OLED)
+- Add I2C Support functions
+
+**Summary of the key new features added to CommandStation-EX V3.0.8**
+
+- Wraps <* *> around DIAGS for the benefit of JMRI
+
+**Summary of the key new features added to CommandStation-EX V3.0.7**
+
+- Implemented support for older 28 apeed step decoders - Option to turn on 28 step speed decoders in addition to 128. If set, all locos will use 28 steps.
+- Improved overload messages with raw values (relative to offset)
+
+**Summary of the key new features added to CommandStation-EX V3.0.6**
+
+- Prevent compiler warning about deprecated B constants
+- Fix Bug that did not let us transmit 5 byte sized packets - 5 Byte commands like PoM (programming on main) were not being sent correctly
+- Support for Huge function numbers (DCC BinaryStateControl) - Support Functions beyond F28
+- <!> ESTOP all - New command to emergency stop all locos on the main track
+- <- [cab]> estop and forget cab/all cabs - Stop and remove loco from the CS. Stops the repeating throttle messages
+- `<D RESET>` command to reboot Arduino
+- Automatic sensor offset detect
+- Improved startup msgs from Motor Drivers (accuracy and auto sense factors)
+- Drop post-write verify - No need to double check CV writes. Writes are now even faster.
+- Allow current sense pin set to UNUSED_PIN - No need to ground an unused analog current pin. Produce startup warning and callback -2 for prog track cmds.
+
+**Summary of the key new features added to CommandStation-EX V3.0.5**
+
+- Fix Fn Key startup with loco ID and fix state change for F16-28
+- Removed ethernet mac config and made it automatic
+- Show wifi ip and port on lcd
+- Auto load config.example.h with warning
+- Dropped example .ino files
+- Corrected .ino comments
+- Add Pololu fault pin handling
+- Waveform speed/simplicity improvements
+- Improved pin speed in waveform
+- Portability to nanoEvery and UnoWifiRev2 CPUs
+- Analog read speed improvements
+- Drop need for DIO2 library
+- Improved current check code
+- Linear command
+- Removed need for ArduinoTimers files
+- Removed option to choose different timer
+- Added EX-RAIL hooks for automation in future version
+- Fixed Turnout list
+- Allow command keywords in mixed case
+- Dropped unused memstream
+- PWM pin accuracy if requirements met
+
+**Summary of the key new features added to CommandStation-EX V3.0.4**
+
+- "Drive-Away" Feature - added so that throttles like Engine Driver can allow a loco to be programmed on a usable, electrically isolated programming track and then drive off onto the main track
+- WiFi Startup Fixes
+
+**Summary of the key new features added to CommandStation-EX V3.0.3**
+
+- Command to write loco address and clear consist
+- Command will allow for consist address
+- Startup commands implemented
+
+**Summary of the key new features added to CommandStation-EX V3.0.2:**
+
+- Create new output for current in mA for `<c>` command - New current response outputs current in mA, overlimit current, and maximum board capable current
+- Simultaneously update JMRI to handle new current meter
+
+**Summary of the key new features added to CommandStation-EX V3.0.1:**
+
+- Add back fix for jitter
+- Add Turnouts, Outputs and Sensors to `<s>` command output
+
+**CommandStation-EX V3.0.0:**
+
+**Release v3.0.0 was a major rewrite if earlier versions of DCC++.  The code base was re-architeced and core changes were made to the Waveform generator to reduce overhead and make better use of Arduino.** **Summary of the key new features added in Release v3.0.0 include:**
+
+- **New USB Browser Based Throttle** - WebThrottle-EX is a full front-end to controller to control the CS to run trains.
+- **WiFi Support** - AP and station modes supported. Auto-detection of an ESP8266 WiFi module with AT firmware on a Mega's serial port. Connection to JMRI and WiThrottle clients.
+- **Withrottle Integrations** - Act as a host for up to four WiThrottle clients concurrently.
+- **Add LCD/OLED support** - OLED supported on Mega only
+- **Improved CV programming routines** - checks for length of CV pulse, and breaks out of the wait state once it has received an ACK, now reading one CV per second.
+- **Improved current sensing** - rewrote current sensing routines for safer operation. Current thresholds based on milliamps, not magic numbers
+- **Individual track power control** - Ability to toggle power on either or both tracks, and to "JOIN" the tracks and make them output the same waveform for multiple power districts.
+- **Single or Dual-Pin PWM output** - Allows control of H-bridges with PH/EN or dual PWM inputs
+- **New, simpler function command** - `<F>` command allows setting functions based on their number, not based on a code as in `<f>`
+- **Function reminders** - Function reminders are sent in addition to speed reminders
+- **Functions to F28** - All NMRA functions are now supported
+- **Filters and user functions** - Ability to filter commands in the parser and execute custom code based on them. (ex: Redirect Turnout commands via NRF24)
+- **Diagnostic `<D>` commands** - See documentation for a full list of new diagnostic commands
+- **Rewrote DCC++ Parser** - more efficient operation, accepts multi-char input and uses less RAM
+- **Rewritten waveform generator** - capable of using any pin for DCC waveform out, eliminating the need for jumpers
+- **Rewritten packet generator** - Simplify and make smaller, remove idea of "registers" from original code
+- **Add free RAM messages** - Free RAM messages are now printed whenever there is a decerase in available RAM
+- **Fix EEPROM bugs**
+- **Number of locos discovery command** - `<#>` command
+- **Support for more locomotives** - 20 locomotives on an UNO and 50 an a Mega.
+- **Automatic slot management** - slot variable in throttle/function commands are ignored and slot management is taken care of automatically. `<->` and `<- CAB>` commands added to release locos from memory and stop packets to the track.
+
+**Key Contributors**
+
+**Project Lead**
+
+- Fred Decker - Holly Springs, North Carolina, USA (FlightRisk)
+
+**CommandStation-EX Developers**
+
+- Chris Harlow - Bournemouth, UK (UKBloke)
+- Harald Barth - Stockholm, Sweden (Haba)
+- Neil McKechnie - Worcestershire, UK (NeilMck)
+- Fred Decker - Holly Springs, North Carolina, USA (FlightRisk)
+- Dave Cutting - Logan, Utah, USA (Dave Cutting/ David Cutting)
+- M Steve Todd -  
+- Scott Catalano - Pennsylvania
+- Gregor Baues - Île-de-France, France (grbba)
+
+**Engine Driver and JMRI Interface**
+
+- M Steve Todd
+
+**exInstaller Software**
+
+- Anthony W - Dayton, Ohio, USA (Dex, Dex++)
+
+**Website and Documentation**
+
+- Mani Kumar - Bangalor, India (Mani / Mani Kumar)
+- Fred Decker - Holly Springs, North Carolina, USA (FlightRisk)
+- Dave Cutting - Logan, Utah, USA (Dave Cutting/ David Cutting)
+- Roger Beschizza - Dorset, UK (Roger Beschizza)
+- Keith Ledbetter - Chicago, Illinois, USA (Keith Ledbetter)
+- Kevin Smith - Rochester Hills, Michigan USA (KC Smith)
+
+**WebThrotle-EX**
+
+- Fred Decker - Holly Springs, NC (FlightRisk/FrightRisk)
+- Mani Kumar - Bangalor, India (Mani /Mani Kumar)
+- Matt H - Somewhere in Europe
+
+**Beta Testing / Release Management / Support**
+
+- Larry Dribin - Release Management
+- Kevin Smith - Rochester Hills, Michigan USA (KC Smith)
+- Keith Ledbetter
+- BradVan der Elst
+- Andrew Pye
+- Mike Bowers
+- Randy McKenzie
+- Roberto Bravin
+- Sim Brigden
+- Alan Lautenslager
+- Martin Bafver
+- Mário André Silva
+- Anthony Kochevar
+- Gajanatha Kobbekaduwe
+- Sumner Patterson
+- Paul - Virginia, USA
+
+**Downloads (zip and tar.gz) below. These are named without version number in the folder name to make the Arduino IDE happy.**
+
+[CommandStation-EX.zip](https://github.com/DCC-EX/CommandStation-EX/releases/download/v3.1.0-Prod/CommandStation-EX.zip)
+[CommandStation-EX.tar.gz](https://github.com/DCC-EX/CommandStation-EX/releases/download/v3.1.0-Prod/CommandStation-EX.tar.gz)

RingStream.cpp

@@ -18,6 +18,7 @@
  */
 
 #include "RingStream.h"
+#include "defines.h"
 #include "DIAG.h"
 
 RingStream::RingStream( const uint16_t len)
@@ -30,27 +31,36 @@ RingStream::RingStream( const uint16_t len)
   _overflow=false;
   _mark=0;
   _count=0; 
+#if defined(ARDUINO_ARCH_ESP32)
+  _bufMux = portMUX_INITIALIZER_UNLOCKED;
+#endif
 }
 
 size_t RingStream::write(uint8_t b) {
   if (_overflow) return 0;
+  portENTER_CRITICAL(&_bufMux);
   _buffer[_pos_write] = b;
   ++_pos_write;
   if (_pos_write==_len) _pos_write=0;
   if (_pos_write==_pos_read) {
     _overflow=true; 
+    portEXIT_CRITICAL(&_bufMux);
     return 0;
   }
   _count++;
+  portEXIT_CRITICAL(&_bufMux);
   return 1;
 }
 
-int RingStream::read() {
-  if ((_pos_read==_pos_write) && !_overflow) return -1;  // empty  
+int RingStream::read(byte advance) {
+  if ((_pos_read==_pos_write) && !_overflow) return -1;  // empty
+  if (_pos_read == _mark) return -1;
+  portENTER_CRITICAL(&_bufMux);
   byte b=_buffer[_pos_read];
-  _pos_read++;
+  _pos_read += advance;
   if (_pos_read==_len) _pos_read=0;
   _overflow=false;
+  portEXIT_CRITICAL(&_bufMux);
   return b;
 }
 
@@ -68,24 +78,41 @@ int RingStream::freeSpace() {
 
 // mark start of message with client id (0...9)
 void RingStream::mark(uint8_t b) {
+    //DIAG(F("Mark1 len=%d count=%d pr=%d pw=%d m=%d"),_len, _count,_pos_read,_pos_write,_mark);
+    portENTER_CRITICAL(&_bufMux);
     _mark=_pos_write;
     write(b); // client id
     write((uint8_t)0);  // count MSB placemarker
     write((uint8_t)0);  // count LSB placemarker
     _count=0;
+    portEXIT_CRITICAL(&_bufMux);
+}
+
+// peekTargetMark is used by the parser stash routines to know which client
+// to send a callback response to some time later. 
+uint8_t RingStream::peekTargetMark() {
+  return _buffer[_mark];
+}
+
+void RingStream::info() {
+  DIAG(F("Info len=%d count=%d pr=%d pw=%d m=%d"),_len, _count,_pos_read,_pos_write,_mark);
 }
 
 bool RingStream::commit() {
+  //DIAG(F("Commit1 len=%d count=%d pr=%d pw=%d m=%d"),_len, _count,_pos_read,_pos_write,_mark);
+  portENTER_CRITICAL(&_bufMux);
   if (_overflow) {
-        DIAG(F("\nRingStream(%d) commit(%d) OVERFLOW\n"),_len, _count);
+        DIAG(F("RingStream(%d) commit(%d) OVERFLOW"),_len, _count);
         // just throw it away 
         _pos_write=_mark;
         _overflow=false;
-        return false; // commit failed
+	portEXIT_CRITICAL(&_bufMux);
+	return false; // commit failed
   }
   if (_count==0) {
     // ignore empty response 
     _pos_write=_mark;
+    portEXIT_CRITICAL(&_bufMux);
     return true; // true=commit ok
   }
   // Go back to the _mark and inject the count 1 byte later
@@ -95,5 +122,8 @@ bool RingStream::commit() {
   _mark++;
   if (_mark==_len) _mark=0;
   _buffer[_mark]=lowByte(_count);
+  _mark=_len+1;
+  //DIAG(F("Commit2 len=%d count=%d pr=%d pw=%d m=%d"),_len, _count,_pos_read,_pos_write,_mark);
+  portEXIT_CRITICAL(&_bufMux);
   return true; // commit worked
 }

RingStream.h

@@ -28,13 +28,17 @@ class RingStream : public Print {
   
     virtual size_t write(uint8_t b);
     using Print::write;
-    int read();
+    inline int read() { return read(1); };
+    inline int peek() { return read(0); };
     int count();
     int freeSpace();
     void mark(uint8_t b);
     bool commit();
+    uint8_t peekTargetMark();
+    void info();
 
  private:
+   int read(byte advance);
    int _len;
    int _pos_write;
    int _pos_read;
@@ -42,6 +46,9 @@ class RingStream : public Print {
    int _mark;
    int _count;
    byte * _buffer;
+#if defined(ARDUINO_ARCH_ESP32)
+   portMUX_TYPE _bufMux;
+#endif
 };
 
 #endif

SSD1306Ascii.cpp

@@ -0,0 +1,399 @@
+/* Based on Arduino SSD1306Ascii Library, Copyright (C) 2015 by William Greiman
+ * Modifications (C) 2021 Neil McKechnie
+ *
+ *  This file is part of CommandStation-EX
+ *
+ * This Library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This Library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with the Arduino SSD1306Ascii Library.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+#include "SSD1306Ascii.h"
+#include "I2CManager.h"
+#include "FSH.h"
+
+//==============================================================================
+// SSD1306/SSD1106 I2C command bytes
+//------------------------------------------------------------------------------
+/** Set Lower Column Start Address for Page Addressing Mode. */
+static const uint8_t SSD1306_SETLOWCOLUMN = 0x00;
+/** Set Higher Column Start Address for Page Addressing Mode. */
+static const uint8_t SSD1306_SETHIGHCOLUMN = 0x10;
+/** Set Memory Addressing Mode. */
+static const uint8_t SSD1306_MEMORYMODE = 0x20;
+/** Set display RAM display start line register from 0 - 63. */
+static const uint8_t SSD1306_SETSTARTLINE = 0x40;
+/** Set Display Contrast to one of 256 steps. */
+static const uint8_t SSD1306_SETCONTRAST = 0x81;
+/** Enable or disable charge pump.  Follow with 0X14 enable, 0X10 disable. */
+static const uint8_t SSD1306_CHARGEPUMP = 0x8D;
+/** Set Segment Re-map between data column and the segment driver. */
+static const uint8_t SSD1306_SEGREMAP = 0xA0;
+/** Resume display from GRAM content. */
+static const uint8_t SSD1306_DISPLAYALLON_RESUME = 0xA4;
+/** Force display on regardless of GRAM content. */
+static const uint8_t SSD1306_DISPLAYALLON = 0xA5;
+/** Set Normal Display. */
+static const uint8_t SSD1306_NORMALDISPLAY = 0xA6;
+/** Set Inverse Display. */
+static const uint8_t SSD1306_INVERTDISPLAY = 0xA7;
+/** Set Multiplex Ratio from 16 to 63. */
+static const uint8_t SSD1306_SETMULTIPLEX = 0xA8;
+/** Set Display off. */
+static const uint8_t SSD1306_DISPLAYOFF = 0xAE;
+/** Set Display on. */
+static const uint8_t SSD1306_DISPLAYON = 0xAF;
+/**Set GDDRAM Page Start Address. */
+static const uint8_t SSD1306_SETSTARTPAGE = 0xB0;
+/** Set COM output scan direction normal. */
+static const uint8_t SSD1306_COMSCANINC = 0xC0;
+/** Set COM output scan direction reversed. */
+static const uint8_t SSD1306_COMSCANDEC = 0xC8;
+/** Set Display Offset. */
+static const uint8_t SSD1306_SETDISPLAYOFFSET = 0xD3;
+/** Sets COM signals pin configuration to match the OLED panel layout. */
+static const uint8_t SSD1306_SETCOMPINS = 0xDA;
+/** This command adjusts the VCOMH regulator output. */
+static const uint8_t SSD1306_SETVCOMDETECT = 0xDB;
+/** Set Display Clock Divide Ratio/ Oscillator Frequency. */
+static const uint8_t SSD1306_SETDISPLAYCLOCKDIV = 0xD5;
+/** Set Pre-charge Period */
+static const uint8_t SSD1306_SETPRECHARGE = 0xD9;
+/** Deactivate scroll */
+static const uint8_t SSD1306_DEACTIVATE_SCROLL = 0x2E;
+/** No Operation Command. */
+static const uint8_t SSD1306_NOP = 0xE3;
+//------------------------------------------------------------------------------
+/** Set Pump voltage value: (30H~33H) 6.4, 7.4, 8.0 (POR), 9.0. */
+static const uint8_t SH1106_SET_PUMP_VOLTAGE = 0x30;
+/** First byte of set charge pump mode */
+static const uint8_t SH1106_SET_PUMP_MODE = 0xAD;
+/** Second byte charge pump on. */
+static const uint8_t SH1106_PUMP_ON = 0x8B;
+/** Second byte charge pump off. */
+static const uint8_t SH1106_PUMP_OFF = 0x8A;
+//------------------------------------------------------------------------------
+
+// Sequence of blank pixels, to optimise clearing screen.
+// Send a maximum of 30 pixels per transmission.
+const uint8_t FLASH SSD1306AsciiWire::blankPixels[30] = 
+  {0x40,        // First byte specifies data mode
+  0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};  
+
+//==============================================================================
+// SSD1306AsciiWire Method Definitions
+//------------------------------------------------------------------------------
+ 
+// Constructor
+SSD1306AsciiWire::SSD1306AsciiWire(int width, int height) {
+  // Set size in characters in base class
+  lcdRows = height / 8;
+  lcdCols = width / 6;
+
+  I2CManager.begin();
+  I2CManager.setClock(400000L);  // Set max supported I2C speed
+  for (byte address = 0x3c; address <= 0x3d; address++) {
+    if (I2CManager.exists(address)) {
+      // Device found
+      DIAG(F("%dx%d OLED display configured on I2C:x%x"), width, height, address);
+      if (width == 132)
+        begin(&SH1106_132x64, address);
+      else if (height == 32)
+        begin(&Adafruit128x32, address);
+      else
+        begin(&Adafruit128x64, address);
+      // Set singleton address
+      lcdDisplay = this;
+      clear();
+      return;
+    }
+  }
+  DIAG(F("OLED display not found"));
+}
+
+/* Clear screen by writing blank pixels. */
+void SSD1306AsciiWire::clearNative() {
+  const int maxBytes = sizeof(blankPixels);  // max number of bytes sendable over Wire
+  for (uint8_t r = 0; r <= m_displayHeight/8 - 1; r++) {
+    setRowNative(r);   // Position at start of row to be erased
+    for (uint8_t c = 0; c <= m_displayWidth - 1; c += maxBytes-1) {
+      uint8_t len = min(m_displayWidth-c, maxBytes-1) + 1;
+      I2CManager.write_P(m_i2cAddr, blankPixels, len);  // Write a number of blank columns
+    }
+  }
+}
+
+// Initialise device
+void SSD1306AsciiWire::begin(const DevType* dev, uint8_t i2cAddr) {
+  m_i2cAddr = i2cAddr;
+  m_col = 0;
+  m_row = 0;
+  const uint8_t* table = (const uint8_t*)GETFLASHW(&dev->initcmds);
+  uint8_t size = GETFLASH(&dev->initSize);
+  m_displayWidth = GETFLASH(&dev->lcdWidth);
+  m_displayHeight = GETFLASH(&dev->lcdHeight);
+  m_colOffset = GETFLASH(&dev->colOffset);
+  I2CManager.write_P(m_i2cAddr, table, size);
+  if (m_displayHeight == 32) 
+    I2CManager.write(m_i2cAddr, 5, 0, // Set command mode
+      SSD1306_SETMULTIPLEX, 0x1F,     // ratio 32
+      SSD1306_SETCOMPINS, 0x02);      // sequential COM pins, disable remap
+}
+
+//------------------------------------------------------------------------------
+
+// Set cursor position (by text line)
+void SSD1306AsciiWire::setRowNative(uint8_t line) {
+  // Calculate pixel position from line number
+  uint8_t row = line*8;
+  if (row < m_displayHeight) {
+    m_row = row;
+    m_col = m_colOffset;
+    // Before using buffer, wait for last request to complete
+    requestBlock.wait();
+    // Build output buffer for I2C
+    uint8_t len = 0;
+    outputBuffer[len++] = 0x00;  // Set to command mode
+    outputBuffer[len++] = SSD1306_SETLOWCOLUMN | (m_col & 0XF);
+    outputBuffer[len++] = SSD1306_SETHIGHCOLUMN | (m_col >> 4);
+    outputBuffer[len++] = SSD1306_SETSTARTPAGE | (m_row/8);
+    I2CManager.write(m_i2cAddr, outputBuffer, len, &requestBlock);
+  }
+}
+//------------------------------------------------------------------------------
+
+// Write a character to the OLED
+size_t SSD1306AsciiWire::writeNative(uint8_t ch) {
+  const uint8_t* base = m_font;
+
+  if (ch < m_fontFirstChar || ch >= (m_fontFirstChar + m_fontCharCount))
+    return 0;
+  // Check if character would be partly or wholly off the display
+  if (m_col + fontWidth > m_displayWidth)
+    return 0;
+#if defined(NOLOWERCASE)
+  // Adjust if lowercase is missing
+  if (ch >= 'a') {
+    if (ch <= 'z')
+      ch = ch - 'a' + 'A';  // Capitalise
+    else
+      ch -= 26; // Allow for missing lowercase letters
+  }
+#endif
+  ch -= m_fontFirstChar;
+  base += fontWidth * ch;
+  // Before using buffer, wait for last request to complete
+  requestBlock.wait();
+  // Build output buffer for I2C
+  outputBuffer[0] = 0x40;     // set SSD1306 controller to data mode
+  uint8_t bufferPos = 1;
+  // Copy character pixel columns
+  for (uint8_t i = 0; i < fontWidth; i++) 
+    outputBuffer[bufferPos++] = GETFLASH(base++);
+  // Add blank pixels between letters
+  for (uint8_t i = 0; i < letterSpacing; i++) 
+    outputBuffer[bufferPos++] = 0;
+
+  // Write the data to I2C display
+  I2CManager.write(m_i2cAddr, outputBuffer, bufferPos, &requestBlock);
+  m_col += fontWidth + letterSpacing;
+  return 1;
+}
+
+//==============================================================================
+// this section is based on https://github.com/adafruit/Adafruit_SSD1306
+
+/** Initialization commands for a 128x32 or 128x64 SSD1306 oled display. */
+const uint8_t FLASH SSD1306AsciiWire::Adafruit128xXXinit[] = {
+    // Init sequence for Adafruit 128x32/64 OLED module
+    0x00,                              // Set to command mode
+    SSD1306_DISPLAYOFF,
+    SSD1306_SETDISPLAYCLOCKDIV, 0x80,  // the suggested ratio 0x80 
+    SSD1306_SETMULTIPLEX, 0x3F,        // ratio 64 (initially)
+    SSD1306_SETDISPLAYOFFSET, 0x0,     // no offset
+    SSD1306_SETSTARTLINE | 0x0,        // line #0
+    SSD1306_CHARGEPUMP, 0x14,          // internal vcc
+    SSD1306_MEMORYMODE, 0x02,          // page mode
+    SSD1306_SEGREMAP | 0x1,            // column 127 mapped to SEG0
+    SSD1306_COMSCANDEC,                // column scan direction reversed
+    SSD1306_SETCOMPINS, 0X12,          // set COM pins
+    SSD1306_SETCONTRAST, 0x7F,         // contrast level 127
+    SSD1306_SETPRECHARGE, 0xF1,        // pre-charge period (1, 15)
+    SSD1306_SETVCOMDETECT, 0x40,       // vcomh regulator level
+    SSD1306_DISPLAYALLON_RESUME,
+    SSD1306_NORMALDISPLAY,
+    SSD1306_DISPLAYON
+};
+
+/** Initialize a 128x32 SSD1306 oled display. */
+const DevType FLASH SSD1306AsciiWire::Adafruit128x32 = {
+  Adafruit128xXXinit,
+  sizeof(Adafruit128xXXinit),
+  128,
+  32,
+  0
+};
+
+/** Initialize a 128x64 oled display. */
+const DevType FLASH SSD1306AsciiWire::Adafruit128x64 = {
+  Adafruit128xXXinit,
+  sizeof(Adafruit128xXXinit),
+  128,
+  64,
+  0
+};
+//------------------------------------------------------------------------------
+// This section is based on https://github.com/stanleyhuangyc/MultiLCD
+
+/** Initialization commands for a 128x64 SH1106 oled display. */
+const uint8_t FLASH SSD1306AsciiWire::SH1106_132x64init[] = {
+  0x00,                                  // Set to command mode
+  SSD1306_DISPLAYOFF,
+  SSD1306_SETDISPLAYCLOCKDIV, 0X80,      // set osc division
+  SSD1306_SETMULTIPLEX, 0x3F,            // ratio 64
+  SSD1306_SETDISPLAYOFFSET, 0X00,        // set display offset
+  SSD1306_SETSTARTPAGE | 0X0,            // set page address
+  SSD1306_SETSTARTLINE | 0x0,            // set start line
+  SH1106_SET_PUMP_MODE, SH1106_PUMP_ON,  // set charge pump enable
+  SSD1306_SEGREMAP | 0X1,                // set segment remap
+  SSD1306_COMSCANDEC,                    // Com scan direction
+  SSD1306_SETCOMPINS, 0X12,              // set COM pins
+  SSD1306_SETCONTRAST, 0x80,             // 128
+  SSD1306_SETPRECHARGE, 0X1F,            // set pre-charge period
+  SSD1306_SETVCOMDETECT,  0x40,          // set vcomh
+  SH1106_SET_PUMP_VOLTAGE | 0X2,         // 8.0 volts
+  SSD1306_NORMALDISPLAY,                 // normal / reverse
+  SSD1306_DISPLAYON
+};
+
+/** Initialize a 132x64 oled SH1106 display. */
+const DevType FLASH SSD1306AsciiWire::SH1106_132x64 =  {
+  SH1106_132x64init,
+  sizeof(SH1106_132x64init),
+  128,
+  64,
+  2    // SH1106 is a 132x64 controller but most OLEDs are only attached
+       // to columns 2-129.
+};
+
+
+//------------------------------------------------------------------------------
+
+// Font characters, 5x7 pixels, 0x61 characters starting at 0x20.
+// Lower case characters optionally omitted.
+const uint8_t FLASH SSD1306AsciiWire::System5x7[] = {
+
+    // Fixed width; char width table not used !!!!
+    // or with lowercase character omitted.
+
+    // font data
+    0x00, 0x00, 0x00, 0x00, 0x00,  // (space)
+    0x00, 0x00, 0x5F, 0x00, 0x00,  // !
+    0x00, 0x07, 0x00, 0x07, 0x00,  // "
+    0x14, 0x7F, 0x14, 0x7F, 0x14,  // #
+    0x24, 0x2A, 0x7F, 0x2A, 0x12,  // $
+    0x23, 0x13, 0x08, 0x64, 0x62,  // %
+    0x36, 0x49, 0x55, 0x22, 0x50,  // &
+    0x00, 0x05, 0x03, 0x00, 0x00,  // '
+    0x00, 0x1C, 0x22, 0x41, 0x00,  // (
+    0x00, 0x41, 0x22, 0x1C, 0x00,  // )
+    0x08, 0x2A, 0x1C, 0x2A, 0x08,  // *
+    0x08, 0x08, 0x3E, 0x08, 0x08,  // +
+    0x00, 0x50, 0x30, 0x00, 0x00,  // ,
+    0x08, 0x08, 0x08, 0x08, 0x08,  // -
+    0x00, 0x60, 0x60, 0x00, 0x00,  // .
+    0x20, 0x10, 0x08, 0x04, 0x02,  // /
+    0x3E, 0x51, 0x49, 0x45, 0x3E,  // 0
+    0x00, 0x42, 0x7F, 0x40, 0x00,  // 1
+    0x42, 0x61, 0x51, 0x49, 0x46,  // 2
+    0x21, 0x41, 0x45, 0x4B, 0x31,  // 3
+    0x18, 0x14, 0x12, 0x7F, 0x10,  // 4
+    0x27, 0x45, 0x45, 0x45, 0x39,  // 5
+    0x3C, 0x4A, 0x49, 0x49, 0x30,  // 6
+    0x01, 0x71, 0x09, 0x05, 0x03,  // 7
+    0x36, 0x49, 0x49, 0x49, 0x36,  // 8
+    0x06, 0x49, 0x49, 0x29, 0x1E,  // 9
+    0x00, 0x36, 0x36, 0x00, 0x00,  // :
+    0x00, 0x56, 0x36, 0x00, 0x00,  // ;
+    0x00, 0x08, 0x14, 0x22, 0x41,  // <
+    0x14, 0x14, 0x14, 0x14, 0x14,  // =
+    0x41, 0x22, 0x14, 0x08, 0x00,  // >
+    0x02, 0x01, 0x51, 0x09, 0x06,  // ?
+    0x32, 0x49, 0x79, 0x41, 0x3E,  // @
+    0x7E, 0x11, 0x11, 0x11, 0x7E,  // A
+    0x7F, 0x49, 0x49, 0x49, 0x36,  // B
+    0x3E, 0x41, 0x41, 0x41, 0x22,  // C
+    0x7F, 0x41, 0x41, 0x22, 0x1C,  // D
+    0x7F, 0x49, 0x49, 0x49, 0x41,  // E
+    0x7F, 0x09, 0x09, 0x01, 0x01,  // F
+    0x3E, 0x41, 0x41, 0x51, 0x32,  // G
+    0x7F, 0x08, 0x08, 0x08, 0x7F,  // H
+    0x00, 0x41, 0x7F, 0x41, 0x00,  // I
+    0x20, 0x40, 0x41, 0x3F, 0x01,  // J
+    0x7F, 0x08, 0x14, 0x22, 0x41,  // K
+    0x7F, 0x40, 0x40, 0x40, 0x40,  // L
+    0x7F, 0x02, 0x04, 0x02, 0x7F,  // M
+    0x7F, 0x04, 0x08, 0x10, 0x7F,  // N
+    0x3E, 0x41, 0x41, 0x41, 0x3E,  // O
+    0x7F, 0x09, 0x09, 0x09, 0x06,  // P
+    0x3E, 0x41, 0x51, 0x21, 0x5E,  // Q
+    0x7F, 0x09, 0x19, 0x29, 0x46,  // R
+    0x46, 0x49, 0x49, 0x49, 0x31,  // S
+    0x01, 0x01, 0x7F, 0x01, 0x01,  // T
+    0x3F, 0x40, 0x40, 0x40, 0x3F,  // U
+    0x1F, 0x20, 0x40, 0x20, 0x1F,  // V
+    0x7F, 0x20, 0x18, 0x20, 0x7F,  // W
+    0x63, 0x14, 0x08, 0x14, 0x63,  // X
+    0x03, 0x04, 0x78, 0x04, 0x03,  // Y
+    0x61, 0x51, 0x49, 0x45, 0x43,  // Z
+    0x00, 0x00, 0x7F, 0x41, 0x41,  // [
+    0x02, 0x04, 0x08, 0x10, 0x20,  // "\"
+    0x41, 0x41, 0x7F, 0x00, 0x00,  // ]
+    0x04, 0x02, 0x01, 0x02, 0x04,  // ^
+    0x40, 0x40, 0x40, 0x40, 0x40,  // _
+    0x00, 0x01, 0x02, 0x04, 0x00,  // `
+#ifndef NOLOWERCASE
+    0x20, 0x54, 0x54, 0x54, 0x78,  // a
+    0x7F, 0x48, 0x44, 0x44, 0x38,  // b
+    0x38, 0x44, 0x44, 0x44, 0x20,  // c
+    0x38, 0x44, 0x44, 0x48, 0x7F,  // d
+    0x38, 0x54, 0x54, 0x54, 0x18,  // e
+    0x08, 0x7E, 0x09, 0x01, 0x02,  // f
+    0x08, 0x14, 0x54, 0x54, 0x3C,  // g
+    0x7F, 0x08, 0x04, 0x04, 0x78,  // h
+    0x00, 0x44, 0x7D, 0x40, 0x00,  // i
+    0x20, 0x40, 0x44, 0x3D, 0x00,  // j
+    0x00, 0x7F, 0x10, 0x28, 0x44,  // k
+    0x00, 0x41, 0x7F, 0x40, 0x00,  // l
+    0x7C, 0x04, 0x18, 0x04, 0x78,  // m
+    0x7C, 0x08, 0x04, 0x04, 0x78,  // n
+    0x38, 0x44, 0x44, 0x44, 0x38,  // o
+    0x7C, 0x14, 0x14, 0x14, 0x08,  // p
+    0x08, 0x14, 0x14, 0x18, 0x7C,  // q
+    0x7C, 0x08, 0x04, 0x04, 0x08,  // r
+    0x48, 0x54, 0x54, 0x54, 0x20,  // s
+    0x04, 0x3F, 0x44, 0x40, 0x20,  // t
+    0x3C, 0x40, 0x40, 0x20, 0x7C,  // u
+    0x1C, 0x20, 0x40, 0x20, 0x1C,  // v
+    0x3C, 0x40, 0x30, 0x40, 0x3C,  // w
+    0x44, 0x28, 0x10, 0x28, 0x44,  // x
+    0x0C, 0x50, 0x50, 0x50, 0x3C,  // y
+    0x44, 0x64, 0x54, 0x4C, 0x44,  // z
+#endif
+    0x00, 0x08, 0x36, 0x41, 0x00,  // {
+    0x00, 0x00, 0x7F, 0x00, 0x00,  // |
+    0x00, 0x41, 0x36, 0x08, 0x00,  // }
+    0x08, 0x08, 0x2A, 0x1C, 0x08,  // ->
+    0x08, 0x1C, 0x2A, 0x08, 0x08,  // <-
+    0x00, 0x06, 0x09, 0x09, 0x06   // degree symbol
+
+};

SSD1306Ascii.h

@@ -0,0 +1,112 @@
+/* Based on Arduino SSD1306Ascii Library, Copyright (C) 2015 by William Greiman
+ * Modifications (C) 2021 Neil McKechnie
+ *
+ *  This file is part of CommandStation-EX
+ *
+ * This Library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This Library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this software.  If not, see
+ * <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef SSD1306Ascii_h
+#define SSD1306Ascii_h
+
+#include "Arduino.h"
+#include "FSH.h"
+#include "LCDDisplay.h"
+
+#include "I2CManager.h"
+#include "DIAG.h"
+
+// Uncomment to remove lower-case letters to save 108 bytes of flash
+//#define NOLOWERCASE
+
+//------------------------------------------------------------------------------
+// Device initialization structure.
+
+struct DevType {
+  /* Pointer to initialization command bytes. */
+  const uint8_t* initcmds;
+  /* Number of initialization bytes */
+  const uint8_t initSize;
+  /* Width of the display in pixels */
+  const uint8_t lcdWidth;
+  /** Height of the display in pixels. */
+  const uint8_t lcdHeight;
+  /* Column offset RAM to display.  Used to pick start column of SH1106. */
+  const uint8_t colOffset;
+};
+
+// Constructor
+class SSD1306AsciiWire : public LCDDisplay {
+ public:
+
+  // Constructor
+  SSD1306AsciiWire(int width, int height);
+
+  // Initialize the display controller.
+  void begin(const DevType* dev, uint8_t i2cAddr);
+
+  // Clear the display and set the cursor to (0, 0).
+  void clearNative() override;
+
+  // Set cursor to start of specified text line
+  void setRowNative(byte line) override;
+
+  // Initialize the display controller.
+  void init(const DevType* dev);
+  
+  // Write one character to OLED
+  size_t writeNative(uint8_t c) override;
+
+  // Display characteristics / initialisation
+  static const DevType FLASH Adafruit128x32;
+  static const DevType FLASH Adafruit128x64;
+  static const DevType FLASH SH1106_132x64;
+
+  bool isBusy() override { return requestBlock.isBusy(); }
+
+ private:
+  // Cursor column.
+  uint8_t m_col;
+  // Cursor RAM row.
+  uint8_t m_row;
+  // Display width.
+  uint8_t m_displayWidth;
+  // Display height.
+  uint8_t m_displayHeight;
+  // Column offset RAM to SEG.
+  uint8_t m_colOffset = 0;
+  // Current font.
+  const uint8_t* const m_font = System5x7;
+
+  // Only fixed size 5x7 fonts in a 6x8 cell are supported.
+  static const uint8_t fontWidth = 5;
+  static const uint8_t fontHeight = 7;
+  static const uint8_t letterSpacing = 1;
+  static const uint8_t m_fontFirstChar = 0x20;
+  static const uint8_t m_fontCharCount = 0x61;
+
+  uint8_t m_i2cAddr;
+
+  I2CRB requestBlock;
+  uint8_t outputBuffer[fontWidth+letterSpacing+1];
+
+  static const uint8_t blankPixels[];
+
+  static const uint8_t System5x7[];
+  static const uint8_t FLASH Adafruit128xXXinit[];
+  static const uint8_t FLASH SH1106_132x64init[];
+};
+
+#endif  // SSD1306Ascii_h

Sensors.cpp

@@ -1,5 +1,6 @@
 /*
  *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2021, modified by Neil McKechnie. All rights reserved.
  *  
  *  This file is part of Asbelos DCC API
  *
@@ -27,9 +28,9 @@ or be allowed to float HIGH if use of the Arduino Pin's internal pull-up resisto
 To ensure proper voltage levels, some part of the Sensor circuitry
 MUST be tied back to the same ground as used by the Arduino.
 
-The Sensor code below utilizes exponential smoothing to "de-bounce" spikes generated by
+The Sensor code below utilises "de-bounce" logic to remove spikes generated by
 mechanical switches and transistors.  This avoids the need to create smoothing circuitry
-for each sensor.  You may need to change these parameters through trial and error for your specific sensors.
+for each sensor.  You may need to change the parameters through trial and error for your specific sensors.
 
 To have this sketch monitor one or more Arduino pins for sensor triggers, first define/edit/delete
 sensor definitions using the following variation of the "S" command:
@@ -68,45 +69,108 @@ decide to ignore the <q ID> return and only react to <Q ID> triggers.
 #include "StringFormatter.h"
 #include "Sensors.h"
 #include "EEStore.h"
+#include "IODevice.h"
 
 
 ///////////////////////////////////////////////////////////////////////////////
-//
-// checks one defined sensors and prints _changed_ sensor state
+// checks a number of defined sensors per entry and prints _changed_ sensor state
 // to stream unless stream is NULL in which case only internal
 // state is updated. Then advances to next sensor which will
-// be checked att next invocation.
+// be checked at next invocation.  Each cycle of reading all sensors will
+// be initiated no more frequently than the time set by 'cycleInterval' microseconds.
 //
+// The list of sensors is divided such that the first part of the list
+// contains sensors that support change notification via callback, and the second
+// part of the list contains sensors that require cyclic polling.  The start of the
+// second part of the list is determined from by the 'firstPollSensor' pointer.
 ///////////////////////////////////////////////////////////////////////////////
 
 void Sensor::checkAll(Print *stream){
+  uint16_t sensorCount = 0;
 
-  if (firstSensor == NULL) return;
-  if (readingSensor == NULL) readingSensor=firstSensor;
+#ifdef USE_NOTIFY
+  // Register the event handler ONCE!
+  if (!inputChangeCallbackRegistered)
+    IONotifyCallback::add(inputChangeCallback);
+  inputChangeCallbackRegistered = true;
+#endif
 
-  bool sensorstate = digitalRead(readingSensor->data.pin);
-
-  if (!sensorstate == readingSensor->active) { // active==true means sensorstate=0/false so sensor unchanged
-    // no change
-    if (readingSensor->latchdelay != 0) {
-      // enable if you want to debug contact jitter
-      //if (stream != NULL) StringFormatter::send(stream, F("JITTER %d %d\n"), 
-      //                                          readingSensor->latchdelay, readingSensor->data.snum);
-       readingSensor->latchdelay=0; // reset
+  if (firstSensor == NULL) return;  // No sensors to be scanned
+  if (readingSensor == NULL) { 
+    // Not currently scanning sensor list
+    unsigned long thisTime = micros();
+    if (thisTime - lastReadCycle >= cycleInterval) {
+      // Required time elapsed since last read cycle started,
+      // so initiate new scan through the sensor list
+      readingSensor = firstSensor;
+      lastReadCycle = thisTime;
     }
-  } else if (readingSensor->latchdelay < 127) { // byte, max 255, good value unknown yet
-    // change but first increase anti-jitter counter
-    readingSensor->latchdelay++;
-  } else {
-    // make the change
-    readingSensor->active = !sensorstate;
-    readingSensor->latchdelay=0; // reset 
-    if (stream != NULL) StringFormatter::send(stream, F("<%c %d>"), readingSensor->active ? 'Q' : 'q', readingSensor->data.snum);
   }
 
-  readingSensor=readingSensor->nextSensor;
+  // Loop until either end of list is encountered or we pause for some reason
+  bool pause = false;
+  while (readingSensor != NULL && !pause) {
+
+    // Where the sensor is attached to a pin, read pin status.  For sources such as LCN,
+    // which don't have an input pin to read, the LCN class calls setState() to update inputState when
+    // a message is received.  The IODevice::read() call returns 1 for active pins (0v) and 0 for inactive (5v).
+    // Also, on HAL drivers that support change notifications, the driver calls the notification callback
+    // routine when an input signal change is detected, and this updates the inputState directly,
+    // so these inputs don't need to be polled here.
+    VPIN pin = readingSensor->data.pin;
+    if (readingSensor->pollingRequired && pin != VPIN_NONE)
+      readingSensor->inputState = IODevice::read(pin);
+
+    // Check if changed since last time, and process changes.
+    if (readingSensor->inputState == readingSensor->active) {
+      // no change
+      readingSensor->latchDelay = minReadCount; // Reset counter
+    } else if (readingSensor->latchDelay > 0) {
+      // change detected, but first decrement delay
+      readingSensor->latchDelay--;
+    } else { 
+      // change validated, act on it.
+      readingSensor->active = readingSensor->inputState;
+      readingSensor->latchDelay = minReadCount;  // Reset counter
+      
+      if (stream != NULL) {
+        StringFormatter::send(stream, F("<%c %d>\n"), readingSensor->active ? 'Q' : 'q', readingSensor->data.snum);
+        pause = true;  // Don't check any more sensors on this entry
+      }
+    }
+
+    // Move to next sensor in list.
+    readingSensor = readingSensor->nextSensor;
+
+    // Currently process max of 16 sensors per entry.
+    // Performance measurements taken during development indicate that, with 128 sensors configured
+    // on 8x 16-pin MCP23017 GPIO expanders with polling (no change notification), all inputs can be read from the devices
+    // within 1.4ms (400Mhz I2C bus speed), and a full cycle of checking 128 sensors for changes takes under a millisecond.
+    sensorCount++;
+    if (sensorCount >= 16) pause = true;
+  }
+
 } // Sensor::checkAll
 
+
+#ifdef USE_NOTIFY
+// Callback from HAL (IODevice class) when a digital input change is recognised.
+// Updates the inputState field, which is subsequently scanned for changes in the checkAll 
+// method.  Ideally the <Q>/<q> message should be sent from here, instead of waiting for
+// the checkAll method, but the output stream is not available at this point.
+void Sensor::inputChangeCallback(VPIN vpin, int state) {
+  Sensor *tt;
+  // This bit is not ideal since it has, potentially, to look through the entire list of
+  // sensors to find the one that has changed.  Ideally this should be improved somehow.
+  for (tt=firstSensor; tt!=NULL ; tt=tt->nextSensor) {
+    if (tt->data.pin == vpin) break;
+  }
+  if (tt != NULL) { // Sensor found
+    tt->inputState = (state != 0); 
+  }
+}
+#endif
+
 ///////////////////////////////////////////////////////////////////////////////
 //
 // prints all sensor states to stream
@@ -115,40 +179,62 @@ void Sensor::checkAll(Print *stream){
 
 void Sensor::printAll(Print *stream){
 
-  for(Sensor * tt=firstSensor;tt!=NULL;tt=tt->nextSensor){
-    if (stream != NULL)
-      StringFormatter::send(stream, F("<%c %d>"), tt->active ? 'Q' : 'q', tt->data.snum);
+  if (stream != NULL) {
+    for(Sensor * tt=firstSensor;tt!=NULL;tt=tt->nextSensor){
+      StringFormatter::send(stream, F("<%c %d>\n"), tt->active ? 'Q' : 'q', tt->data.snum);
+    }
   } // loop over all sensors
 } // Sensor::printAll
 
 ///////////////////////////////////////////////////////////////////////////////
+// Static Function to create/find Sensor object.
 
-Sensor *Sensor::create(int snum, int pin, int pullUp){
+Sensor *Sensor::create(int snum, VPIN pin, int pullUp){
   Sensor *tt;
 
-  if(firstSensor==NULL){
-    firstSensor=(Sensor *)calloc(1,sizeof(Sensor));
-    tt=firstSensor;
-  } else if((tt=get(snum))==NULL){
-    tt=firstSensor;
-    while(tt->nextSensor!=NULL)
-      tt=tt->nextSensor;
-    tt->nextSensor=(Sensor *)calloc(1,sizeof(Sensor));
-    tt=tt->nextSensor;
-  }
+  if (pin > VPIN_MAX && pin != VPIN_NONE) return NULL;
 
-  if(tt==NULL) return tt;       // problem allocating memory
+  remove(snum);  // Unlink and free any existing sensor with the same id, before creating the new one.
 
-  tt->data.snum=snum;
-  tt->data.pin=pin;
-  tt->data.pullUp=(pullUp==0?LOW:HIGH);
-  tt->active=false;
-  tt->latchdelay=0;
-  pinMode(pin,INPUT);         // set mode to input
-  digitalWrite(pin,pullUp);   // don't use Arduino's internal pull-up resistors for external infrared sensors --- each sensor must have its own 1K external pull-up resistor
+  tt = (Sensor *)calloc(1,sizeof(Sensor));
+  if (!tt) return tt;     // memory allocation failure
+
+  if (pin == VPIN_NONE) 
+    tt->pollingRequired = false;
+  #ifdef USE_NOTIFY
+  else if (IODevice::hasCallback(pin)) 
+    tt->pollingRequired = false;
+  #endif
+  else 
+    tt->pollingRequired = true;
+
+  // Add to the start of the list
+  tt->nextSensor = firstSensor;
+  firstSensor = tt;
+
+  tt->data.snum = snum;
+  tt->data.pin = pin;
+  tt->data.pullUp = pullUp;
+  tt->active = 0;
+  tt->inputState = 0;
+  tt->latchDelay = minReadCount;
+
+  if (pin != VPIN_NONE) 
+    IODevice::configureInput(pin, pullUp);   
+    // Generally, internal pull-up resistors are not, on their own, sufficient 
+    // for external infrared sensors --- each sensor must have its own 1K external pull-up resistor
 
   return tt;
+}
 
+///////////////////////////////////////////////////////////////////////////////
+// Object method to directly change the input state, for sensors such as LCN which are updated
+//  by means other than by polling an input.
+
+void Sensor::setState(int value) {
+  // Trigger sensor change to be reported on next checkAll loop.
+  inputState = (value != 0);
+  latchDelay = 0; // Don't wait for anti-jitter logic
 }
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -166,13 +252,23 @@ bool Sensor::remove(int n){
   for(tt=firstSensor;tt!=NULL && tt->data.snum!=n;pp=tt,tt=tt->nextSensor);
 
   if (tt==NULL)  return false;
-  
-  if(tt==firstSensor)
-    firstSensor=tt->nextSensor;
-  else
-    pp->nextSensor=tt->nextSensor;
 
+  // Unlink the sensor from the list
+  if(tt==firstSensor) 
+    firstSensor=tt->nextSensor;
+  else 
+    pp->nextSensor=tt->nextSensor;
+#ifdef USE_NOTIFY
+  if (tt==lastSensor)
+    lastSensor = pp;
+  if (tt==firstPollSensor)
+    firstPollSensor = tt->nextSensor;
+#endif
+
+  // Check if the sensor being deleted is the next one to be read.  If so, 
+  // make the following one the next one to be read.
   if (readingSensor==tt) readingSensor=tt->nextSensor;
+
   free(tt);
 
   return true;
@@ -184,9 +280,10 @@ void Sensor::load(){
   struct SensorData data;
   Sensor *tt;
 
-  for(int i=0;i<EEStore::eeStore->data.nSensors;i++){
+  uint16_t i=EEStore::eeStore->data.nSensors;
+  while(i--){
     EEPROM.get(EEStore::pointer(),data);
-    tt=create(data.snum,data.pin,data.pullUp);
+    tt=create(data.snum, data.pin, data.pullUp);
     EEStore::advance(sizeof(tt->data));
   }
 }
@@ -211,3 +308,10 @@ void Sensor::store(){
 
 Sensor *Sensor::firstSensor=NULL;
 Sensor *Sensor::readingSensor=NULL;
+unsigned long Sensor::lastReadCycle=0;
+
+#ifdef USE_NOTIFY
+Sensor *Sensor::firstPollSensor = NULL;
+Sensor *Sensor::lastSensor = NULL;
+bool Sensor::inputChangeCallbackRegistered = false;
+#endif

Sensors.h

@@ -20,29 +20,74 @@
 #define Sensor_h
 
 #include "Arduino.h"
+#include "IODevice.h"
 
-#define  SENSOR_DECAY  0.03
+// Uncomment the following #define statement to use callback notification
+//  where the driver supports it.
+//  The principle of callback notification is to avoid the Sensor class
+//  having to poll the device driver cyclically for input values, and then scan 
+//  for changes.  Instead, when the driver scans the inputs, if it detects
+//  a change it invokes a callback function in the Sensor class.  In the current
+//  implementation, the advantages are limited because (a) the Sensor class 
+//  performs debounce checks, and (b) the Sensor class does not have a 
+//  static reference to the output stream for sending <Q>/<q> messages
+//  when a change is detected.  These restrictions mean that the checkAll() 
+//  method still has to iterate through all of the Sensor objects looking 
+//  for changes.
+#define USE_NOTIFY
 
 struct SensorData {
   int snum;
-  uint8_t pin;
+  VPIN pin;
   uint8_t pullUp;
 };
 
-struct Sensor{
-  static Sensor *firstSensor;
-  static Sensor *readingSensor;
+class Sensor{
+  // The sensor list is a linked list where each sensor's 'nextSensor' field points to the next.
+  //   The pointer is null in the last on the list.
+
+public:
   SensorData data;
-  boolean active;
-  byte latchdelay;
+  struct {
+    uint8_t active:1;
+    uint8_t inputState:1;
+    uint8_t latchDelay:6;
+  };   // bit 7=active; bit 6=input state; bits 5-0=latchDelay
+
+  static Sensor *firstSensor;
+#ifdef USE_NOTIFY
+  static Sensor *firstPollSensor;
+  static Sensor *lastSensor;
+#endif
+  // readingSensor points to the next sensor to be polled, or null if the poll cycle is completed for
+  // the period.
+  static Sensor *readingSensor;
+
+  // Constructor
+  Sensor(); 
   Sensor *nextSensor;
+
+  void setState(int state);
   static void load();
   static void store();
-  static Sensor *create(int, int, int);
-  static Sensor* get(int);  
-  static bool remove(int);  
-  static void checkAll(Print *);
-  static void printAll(Print *);
+  static Sensor *create(int id, VPIN vpin, int pullUp);
+  static Sensor* get(int id);  
+  static bool remove(int id);  
+  static void checkAll(Print *stream);
+  static void printAll(Print *stream);
+  static unsigned long lastReadCycle; // value of micros at start of last read cycle
+  static const unsigned int cycleInterval = 10000; // min time between consecutive reads of each sensor in microsecs.
+                                                   // should not be less than device scan cycle time.
+  static const unsigned int minReadCount = 1; // number of additional scans before acting on change
+                                        // E.g. 1 means that a change is ignored for one scan and actioned on the next.
+                                        // Max value is 63
+  bool pollingRequired = true;
+
+#ifdef USE_NOTIFY
+  static void inputChangeCallback(VPIN vpin, int state);
+  static bool inputChangeCallbackRegistered;
+#endif
+  
 }; // Sensor
 
 #endif

StringFormatter.cpp

@@ -22,13 +22,9 @@
 #if defined(ARDUINO_ARCH_SAMD)
    // Some processors use a gcc compiler that renames va_list!!!
   #include <cstdarg>
-  Print * StringFormatter::diagSerial= &SerialUSB;
-  
-#elif defined(ARDUINO_ARCH_AVR)
-  Print * StringFormatter::diagSerial= &Serial;
-#elif defined(ARDUINO_ARCH_MEGAAVR)
+  Print * StringFormatter::diagSerial= &SerialUSB; 
+#else
   Print * StringFormatter::diagSerial=&Serial;
-  #define __FlashStringHelper char
 #endif
 
 #include "LCDDisplay.h"
@@ -38,23 +34,26 @@ bool Diag::CMD=false;
 bool Diag::WIFI=false;
 bool Diag::WITHROTTLE=false;
 bool Diag::ETHERNET=false;
+bool Diag::LCN=false;
 
  
-void StringFormatter::diag( const __FlashStringHelper* input...) {
-  if (!diagSerial) return;    
+void StringFormatter::diag( const FSH* input...) {
+  if (!diagSerial) return; 
+  diagSerial->print(F("<* "));   
   va_list args;
   va_start(args, input);
   send2(diagSerial,input,args);
+  diagSerial->print(F(" *>\n"));
 }
 
-void StringFormatter::lcd(byte row, const __FlashStringHelper* input...) {
+void StringFormatter::lcd(byte row, const FSH* input...) {
   va_list args;
 
   // Issue the LCD as a diag first
-  diag(F("\nLCD%d:"),row);
+  send(diagSerial,F("<* LCD%d:"),row);
   va_start(args, input);
   send2(diagSerial,input,args);
-  diag(F("\n"));
+  send(diagSerial,F(" *>\n"));
   
   if (!LCDDisplay::lcdDisplay) return;
   LCDDisplay::lcdDisplay->setRow(row);    
@@ -62,25 +61,25 @@ void StringFormatter::lcd(byte row, const __FlashStringHelper* input...) {
   send2(LCDDisplay::lcdDisplay,input,args);
 }
 
-void StringFormatter::send(Print * stream, const __FlashStringHelper* input...) {
+void StringFormatter::send(Print * stream, const FSH* input...) {
   va_list args;
   va_start(args, input);
   send2(stream,input,args);
 }
 
-void StringFormatter::send(Print & stream, const __FlashStringHelper* input...) {
+void StringFormatter::send(Print & stream, const FSH* input...) {
   va_list args;
   va_start(args, input);
   send2(&stream,input,args);
 }
 
-void StringFormatter::send2(Print * stream,const __FlashStringHelper* format, va_list args) {
+void StringFormatter::send2(Print * stream,const FSH* format, va_list args) {
     
   // thanks to Jan Turoň  https://arduino.stackexchange.com/questions/56517/formatting-strings-in-arduino-for-output
 
   char* flash=(char*)format;
   for(int i=0; ; ++i) {
-    char c=pgm_read_byte_near(flash+i);
+    char c=GETFLASH(flash+i);
     if (c=='\0') return;
     if(c!='%') { stream->print(c); continue; }
 
@@ -91,14 +90,14 @@ void StringFormatter::send2(Print * stream,const __FlashStringHelper* format, va
     
     formatContinues=false;
     i++;
-    c=pgm_read_byte_near(flash+i);
+    c=GETFLASH(flash+i);
     switch(c) {
       case '%': stream->print('%'); break;
       case 'c': stream->print((char) va_arg(args, int)); break;
       case 's': stream->print(va_arg(args, char*)); break;
       case 'e': printEscapes(stream,va_arg(args, char*)); break;
-      case 'E': printEscapes(stream,(const __FlashStringHelper*)va_arg(args, char*)); break;
-      case 'S': stream->print((const __FlashStringHelper*)va_arg(args, char*)); break;
+      case 'E': printEscapes(stream,(const FSH*)va_arg(args, char*)); break;
+      case 'S': stream->print((const FSH*)va_arg(args, char*)); break;
       case 'd': printPadded(stream,va_arg(args, int), formatWidth, formatLeft); break;
       case 'l': printPadded(stream,va_arg(args, long), formatWidth, formatLeft); break;
       case 'b': stream->print(va_arg(args, int), BIN); break;
@@ -138,12 +137,12 @@ void StringFormatter::printEscapes(Print * stream,char * input) {
  }
 }
 
-void StringFormatter::printEscapes(Print * stream, const __FlashStringHelper * input) {
+void StringFormatter::printEscapes(Print * stream, const FSH * input) {
  
  if (!stream) return;
  char* flash=(char*)input;
  for(int i=0; ; ++i) {
-  char c=pgm_read_byte_near(flash+i);
+  char c=GETFLASH(flash+i);
   printEscape(stream,c);
   if (c=='\0') return;
  }

StringFormatter.h

@@ -19,12 +19,10 @@
 #ifndef StringFormatter_h
 #define StringFormatter_h
 #include <Arduino.h>
-
+#include "FSH.h"
 #if defined(ARDUINO_ARCH_SAMD)
    // Some processors use a gcc compiler that renames va_list!!!
   #include <cstdarg>  
-#elif defined(ARDUINO_ARCH_MEGAAVR)
-  #define __FlashStringHelper char
 #endif
 
 #include "LCDDisplay.h"
@@ -35,28 +33,29 @@ class Diag {
   static bool WIFI;
   static bool WITHROTTLE;
   static bool ETHERNET;
+  static bool LCN;
   
 };
 
 class StringFormatter
 {
   public:
-    static void send(Print * serial, const __FlashStringHelper* input...);
-    static void send(Print & serial, const __FlashStringHelper* input...);
+    static void send(Print * serial, const FSH* input...);
+    static void send(Print & serial, const FSH* input...);
     
     static void printEscapes(Print * serial,char * input);
-    static void printEscapes(Print * serial,const __FlashStringHelper* input);
+    static void printEscapes(Print * serial,const FSH* input);
     static void printEscape(Print * serial, char c);
 
     // DIAG support
     static Print * diagSerial;
-    static void diag( const __FlashStringHelper* input...);
-    static void lcd(byte row, const __FlashStringHelper* input...);
+    static void diag( const FSH* input...);
+    static void lcd(byte row, const FSH* input...);
     static void printEscapes(char * input);
     static void printEscape( char c);
 
     private: 
-    static void send2(Print * serial, const __FlashStringHelper* input,va_list args);
+    static void send2(Print * serial, const FSH* input,va_list args);
     static void printPadded(Print* stream, long value, byte width, bool formatLeft);
 
 };

Timer.cpp

@@ -1,94 +0,0 @@
-// This file is copied from https://github.com/davidcutting42/ArduinoTimers
-// All Credit to David Cutting
-
-#include <Arduino.h>
-
-#if defined(ARDUINO_SAMD_ZERO)
-
-#if defined(SAMC21)
-#include "ATSAMC21G/Timer.h"
-#else
-#include "ATSAMD21G/Timer.h"
-#endif
-
-Timer TimerA(TCC0);
-Timer TimerB(TCC1);
-Timer TimerC(TCC2);
-
-void TCC0_Handler() {
-    if(TCC0->INTFLAG.bit.OVF) {
-        TCC0->INTFLAG.bit.OVF = 1;
-        TimerA.isrCallback();
-    }
-}
-
-void TCC1_Handler() {
-    if(TCC1->INTFLAG.bit.OVF) {
-        TCC1->INTFLAG.bit.OVF = 1;
-        TimerB.isrCallback();
-    }
-}
-
-void TCC2_Handler() {
-    if(TCC2->INTFLAG.bit.OVF) {
-        TCC2->INTFLAG.bit.OVF = 1;
-        TimerC.isrCallback();
-    }
-}
-#elif defined(ARDUINO_AVR_MEGA) || defined(ARDUINO_AVR_MEGA2560)
-
-#include "ATMEGA2560/Timer.h"
-
-Timer TimerA(1);
-Timer TimerB(3);
-Timer TimerC(4);
-Timer TimerD(5);
-
-ISR(TIMER1_OVF_vect)
-{
-    TimerA.isrCallback();
-}
-
-ISR(TIMER3_OVF_vect)
-{
-    TimerB.isrCallback();
-}
-
-ISR(TIMER4_OVF_vect)
-{
-    TimerC.isrCallback();
-}
-
-ISR(TIMER5_OVF_vect)
-{
-    TimerD.isrCallback();
-}
-
-#elif defined(ARDUINO_AVR_UNO)      // Todo: add other 328 boards for compatibility
-
-#include "ATMEGA328/Timer.h"
-
-Timer TimerA(1);
-Timer TimerB(2);
-
-ISR(TIMER1_OVF_vect)
-{
-    TimerA.isrCallback();
-}
-
-ISR(TIMER2_OVF_vect)
-{
-    TimerB.isrCallback();
-}
-
-#elif defined(ARDUINO_ARCH_MEGAAVR)
-
-#include "ATMEGA4809/Timer.h"
-
-Timer TimerA(0);
-
-ISR(TCA0_OVF_vect) {
-    TimerA.isrCallback();
-}
-
-#endif

Turnouts.cpp

@@ -1,4 +1,5 @@
 /*
+ *  © 2021 Restructured Neil McKechnie
  *  © 2013-2016 Gregg E. Berman
  *  © 2020, Chris Harlow. All rights reserved.
  *  © 2020, Harald Barth.
@@ -18,151 +19,507 @@
  *  You should have received a copy of the GNU General Public License
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
-#include "Turnouts.h"
+
+
+#include "defines.h"  // includes config.h
 #include "EEStore.h"
-#include "PWMServoDriver.h"
+#include "StringFormatter.h"
+#include "RMFT2.h"
+#include "Turnouts.h"
+#include "DCC.h"
+#include "LCN.h"
 #ifdef EESTOREDEBUG
 #include "DIAG.h"
 #endif
 
-bool Turnout::activate(int n,bool state){
-#ifdef EESTOREDEBUG
-  DIAG(F("\nTurnout::activate(%d,%d)\n"),n,state);
-#endif
-  Turnout * tt=get(n);
-  if (tt==NULL) return false;
-  tt->activate(state);
-  EEStore::store();
-  turnoutlistHash++;
-  return true;
-}
+  /* 
+   * Protected static data
+   */ 
 
-bool Turnout::isActive(int n){
-  Turnout * tt=get(n);
-  if (tt==NULL) return false;
-  return tt->data.tStatus & STATUS_ACTIVE;
-}
+  /* static */ Turnout *Turnout::_firstTurnout = 0;
 
-// activate is virtual here so that it can be overridden by a non-DCC turnout mechanism
-void Turnout::activate(bool state) {
-#ifdef EESTOREDEBUG
-  DIAG(F("\nTurnout::activate(%d)\n"),state);
-#endif
-  if (state)
-    data.tStatus|=STATUS_ACTIVE;
-  else
-    data.tStatus &= ~STATUS_ACTIVE;
-  if (data.tStatus & STATUS_PWM)
-    PWMServoDriver::setServo(data.tStatus & STATUS_PWMPIN, (data.inactiveAngle+(state?data.moveAngle:0)));
-  else
-    DCC::setAccessory(data.address,data.subAddress, state);
-  EEStore::store();
-}
-///////////////////////////////////////////////////////////////////////////////
+  /* 
+   * Public static data
+   */
+  /* static */ int Turnout::turnoutlistHash = 0;
+ 
+  /*
+   * Protected static functions
+   */
 
-Turnout* Turnout::get(int n){
-  Turnout *tt;
-  for(tt=firstTurnout;tt!=NULL && tt->data.id!=n;tt=tt->nextTurnout);
-  return(tt);
-}
-///////////////////////////////////////////////////////////////////////////////
-
-bool Turnout::remove(int n){
-  Turnout *tt,*pp=NULL;
-
-  for(tt=firstTurnout;tt!=NULL && tt->data.id!=n;pp=tt,tt=tt->nextTurnout);
-
-  if(tt==NULL) return false;
-  
-  if(tt==firstTurnout)
-    firstTurnout=tt->nextTurnout;
-  else
-    pp->nextTurnout=tt->nextTurnout;
-
-  free(tt);
-  turnoutlistHash++;
-  return true; 
-}
-
-///////////////////////////////////////////////////////////////////////////////
-
-void Turnout::load(){
-  struct TurnoutData data;
-  Turnout *tt;
-
-  for(int i=0;i<EEStore::eeStore->data.nTurnouts;i++){
-    EEPROM.get(EEStore::pointer(),data);
-    if (data.tStatus & STATUS_PWM) tt=create(data.id,data.tStatus & STATUS_PWMPIN, data.inactiveAngle,data.moveAngle);
-    else tt=create(data.id,data.address,data.subAddress);
-    tt->data.tStatus=data.tStatus;
-    EEStore::advance(sizeof(tt->data));
-#ifdef EESTOREDEBUG
-    tt->print(tt);
-#endif
-  }
-}
-
-///////////////////////////////////////////////////////////////////////////////
-
-void Turnout::store(){
-  Turnout *tt;
-
-  tt=firstTurnout;
-  EEStore::eeStore->data.nTurnouts=0;
-
-  while(tt!=NULL){
-#ifdef EESTOREDEBUG
-    tt->print(tt);
-#endif
-    EEPROM.put(EEStore::pointer(),tt->data);
-    EEStore::advance(sizeof(tt->data));
-    tt=tt->nextTurnout;
-    EEStore::eeStore->data.nTurnouts++;
+  /* static */ Turnout *Turnout::get(uint16_t id) {
+    // Find turnout object from list.
+    for (Turnout *tt = _firstTurnout; tt != NULL; tt = tt->_nextTurnout)
+      if (tt->_turnoutData.id == id) return tt;
+    return NULL;
   }
 
-}
-///////////////////////////////////////////////////////////////////////////////
-
-Turnout *Turnout::create(int id, int add, int subAdd){
-  Turnout *tt=create(id);
-  tt->data.address=add;
-  tt->data.subAddress=subAdd;
-  tt->data.tStatus=0;
-  return(tt);
-}
-
-Turnout *Turnout::create(int id, byte pin, int activeAngle, int inactiveAngle){
-  Turnout *tt=create(id);
-  tt->data.tStatus= STATUS_PWM | (pin &  STATUS_PWMPIN);
-  tt->data.inactiveAngle=inactiveAngle;
-  tt->data.moveAngle=activeAngle-inactiveAngle;
-  return(tt);
-}
-
-Turnout *Turnout::create(int id){
-  Turnout *tt=get(id);
-  if (tt==NULL) { 
-     tt=(Turnout *)calloc(1,sizeof(Turnout));
-     tt->nextTurnout=firstTurnout;
-     firstTurnout=tt;
-     tt->data.id=id;
+  // Add new turnout to end of chain
+  /* static */ void Turnout::add(Turnout *tt) {
+    if (!_firstTurnout) 
+      _firstTurnout = tt;
+    else {
+      // Find last object on chain
+      Turnout *ptr = _firstTurnout;
+      for ( ; ptr->_nextTurnout!=0; ptr=ptr->_nextTurnout) {}
+      // Line new object to last object.
+      ptr->_nextTurnout = tt;
     }
-  turnoutlistHash++;
-  return tt;
+    turnoutlistHash++;
+  }
+  
+  // For DCC++ classic compatibility, state reported to JMRI is 1 for thrown and 0 for closed; 
+  void Turnout::printState(Print *stream) { 
+    StringFormatter::send(stream, F("<H %d %d>\n"), 
+      _turnoutData.id, !_turnoutData.closed);
   }
 
-///////////////////////////////////////////////////////////////////////////////
-//
-// print debug info about the state of a turnout
-//
-#ifdef EESTOREDEBUG
-void Turnout::print(Turnout *tt) {
-    if (tt->data.tStatus & STATUS_PWM )
-      DIAG(F("Turnout %d ZeroAngle %d MoveAngle %d Status %d\n"),tt->data.id, tt->data.inactiveAngle, tt->data.moveAngle,tt->data.tStatus & STATUS_ACTIVE);
+  // Remove nominated turnout from turnout linked list and delete the object.
+  /* static */ bool Turnout::remove(uint16_t id) {
+    Turnout *tt,*pp=NULL;
+
+    for(tt=_firstTurnout; tt!=NULL && tt->_turnoutData.id!=id; pp=tt, tt=tt->_nextTurnout) {}
+    if (tt == NULL) return false;
+    
+    if (tt == _firstTurnout)
+      _firstTurnout = tt->_nextTurnout;
     else
-	DIAG(F("Turnout %d Addr %d Subaddr %d Status %d\n"),tt->data.id, tt->data.address, tt->data.subAddress,tt->data.tStatus & STATUS_ACTIVE);
-}
+      pp->_nextTurnout = tt->_nextTurnout;
+
+    delete (ServoTurnout *)tt;
+
+    turnoutlistHash++;
+    return true; 
+  } 
+
+
+  /*
+   * Public static functions
+   */
+
+  /* static */ bool Turnout::isClosed(uint16_t id) {
+    Turnout *tt = get(id);
+    if (tt) 
+      return tt->isClosed();
+    else
+      return false;
+  }
+
+  /* static */ bool Turnout::setClosedStateOnly(uint16_t id, bool closeFlag) {
+    Turnout *tt = get(id);
+    if (!tt) return false;
+    tt->_turnoutData.closed = closeFlag;
+
+    // I know it says setClosedStateOnly, but we need to tell others
+    //  that the state has changed too.
+    #if defined(RMFT_ACTIVE)
+      RMFT2::turnoutEvent(id, closeFlag);
+    #endif
+
+      // Send message to JMRI etc. over Serial USB.  This is done here
+      // to ensure that the message is sent when the turnout operation
+      // is not initiated by a Serial command.
+      tt->printState(&Serial);
+    return true;
+  }
+
+
+  // Static setClosed function is invoked from close(), throw() etc. to perform the 
+  //  common parts of the turnout operation.  Code which is specific to a turnout
+  //  type should be placed in the virtual function setClosedInternal(bool) which is
+  //  called from here.
+  /* static */ bool Turnout::setClosed(uint16_t id, bool closeFlag) { 
+  #if defined(DIAG_IO)
+    if (closeFlag) 
+      DIAG(F("Turnout::close(%d)"), id);
+    else
+      DIAG(F("Turnout::throw(%d)"), id);
+  #endif
+    Turnout *tt = Turnout::get(id);
+    if (!tt) return false;
+    bool ok = tt->setClosedInternal(closeFlag);
+
+    if (ok) {
+      turnoutlistHash++;  // let withrottle know something changed
+    
+      // Write byte containing new closed/thrown state to EEPROM if required.  Note that eepromAddress
+      // is always zero for LCN turnouts.
+      if (EEStore::eeStore->data.nTurnouts > 0 && tt->_eepromAddress > 0) 
+        EEPROM.put(tt->_eepromAddress, tt->_turnoutData.flags);  
+
+    #if defined(RMFT_ACTIVE)
+      RMFT2::turnoutEvent(id, closeFlag);
+    #endif
+
+      // Send message to JMRI etc. over Serial USB.  This is done here
+      // to ensure that the message is sent when the turnout operation
+      // is not initiated by a Serial command.
+      tt->printState(&Serial);
+    }
+    return ok;
+  }
+
+  // Load all turnout objects
+  /* static */ void Turnout::load() {
+    for (uint16_t i=0; i<EEStore::eeStore->data.nTurnouts; i++) {
+      Turnout::loadTurnout();
+    }
+  }
+
+  // Save all turnout objects
+  /* static */ void Turnout::store() {
+    EEStore::eeStore->data.nTurnouts=0;
+    for (Turnout *tt = _firstTurnout; tt != 0; tt = tt->_nextTurnout) {
+      tt->save();
+      EEStore::eeStore->data.nTurnouts++;
+    }
+  }
+
+  // Load one turnout from EEPROM
+  /* static */ Turnout *Turnout::loadTurnout () {
+    Turnout *tt = 0;
+    // Read turnout type from EEPROM
+    struct TurnoutData turnoutData;
+    int eepromAddress = EEStore::pointer() + offsetof(struct TurnoutData, flags); // Address of byte containing the closed flag.
+    EEPROM.get(EEStore::pointer(), turnoutData);
+    EEStore::advance(sizeof(turnoutData));
+
+    switch (turnoutData.turnoutType) {
+      case TURNOUT_SERVO:
+        // Servo turnout
+        tt = ServoTurnout::load(&turnoutData);
+        break;
+      case TURNOUT_DCC:
+        // DCC Accessory turnout
+        tt = DCCTurnout::load(&turnoutData);
+        break;
+      case TURNOUT_VPIN:
+        // VPIN turnout
+        tt = VpinTurnout::load(&turnoutData);
+        break;
+      default:
+        // If we find anything else, then we don't know what it is or how long it is, 
+        // so we can't go any further through the EEPROM!
+        return NULL;
+    }
+    if (tt) {
+      // Save EEPROM address in object.  Note that LCN turnouts always have eepromAddress of zero.
+      tt->_eepromAddress = eepromAddress + offsetof(struct TurnoutData, flags);
+    }
+
+#ifdef EESTOREDEBUG
+    printAll(&Serial);
+#endif
+    return tt;
+  }
+
+  // Display, on the specified stream, the current state of the turnout (1=thrown or 0=closed).
+  /* static */ void Turnout::printState(uint16_t id, Print *stream) {
+    Turnout *tt = get(id);
+    if (tt) tt->printState(stream);
+  }
+
+
+/*************************************************************************************
+ * ServoTurnout - Turnout controlled by servo device.
+ * 
+ *************************************************************************************/
+
+  // Private Constructor
+  ServoTurnout::ServoTurnout(uint16_t id, VPIN vpin, uint16_t thrownPosition, uint16_t closedPosition, uint8_t profile, bool closed) :
+    Turnout(id, TURNOUT_SERVO, closed) 
+  {
+    _servoTurnoutData.vpin = vpin;
+    _servoTurnoutData.thrownPosition = thrownPosition; 
+    _servoTurnoutData.closedPosition = closedPosition;
+    _servoTurnoutData.profile = profile;
+  }
+
+  // Create function
+  /* static */ Turnout *ServoTurnout::create(uint16_t id, VPIN vpin, uint16_t thrownPosition, uint16_t closedPosition, uint8_t profile, bool closed) {
+#ifndef IO_NO_HAL
+    Turnout *tt = get(id);
+    if (tt) { 
+      // Object already exists, check if it is usable
+      if (tt->isType(TURNOUT_SERVO)) {
+        // Yes, so set parameters
+        ServoTurnout *st = (ServoTurnout *)tt;
+        st->_servoTurnoutData.vpin = vpin;
+        st->_servoTurnoutData.thrownPosition = thrownPosition;
+        st->_servoTurnoutData.closedPosition = closedPosition;
+        st->_servoTurnoutData.profile = profile;
+        // Don't touch the _closed parameter, retain the original value.
+
+        // We don't really need to do the following, since a call to IODevice::_writeAnalogue 
+        //  will provide all the data that is required!  However, if someone has configured 
+        //  a Turnout, we should ensure that the SET() RESET() and other commands that use write() 
+        //  behave consistently with the turnout commands.
+        IODevice::configureServo(vpin, thrownPosition, closedPosition, profile, 0, closed);
+
+        // Set position directly to specified position - we don't know where it is moving from.
+        IODevice::writeAnalogue(vpin, closed ? closedPosition : thrownPosition, PCA9685::Instant);
+
+        return tt;
+      } else {
+        // Incompatible object, delete and recreate
+        remove(id);
+      }
+    }
+    tt = (Turnout *)new ServoTurnout(id, vpin, thrownPosition, closedPosition, profile, closed);
+    IODevice::writeAnalogue(vpin, closed ? closedPosition : thrownPosition, PCA9685::Instant);
+    return tt;
+#else
+    (void)id; (void)vpin; (void)thrownPosition; (void)closedPosition;
+    (void)profile; (void)closed;          // avoid compiler warnings.
+    return NULL;
+#endif
+  }
+
+  // Load a Servo turnout definition from EEPROM.  The common Turnout data has already been read at this point.
+  Turnout *ServoTurnout::load(struct TurnoutData *turnoutData) {
+    ServoTurnoutData servoTurnoutData;
+    // Read class-specific data from EEPROM
+    EEPROM.get(EEStore::pointer(), servoTurnoutData);
+    EEStore::advance(sizeof(servoTurnoutData));
+    
+    // Create new object
+    Turnout *tt = ServoTurnout::create(turnoutData->id, servoTurnoutData.vpin, servoTurnoutData.thrownPosition,
+      servoTurnoutData.closedPosition, servoTurnoutData.profile, turnoutData->closed);
+    return tt;
+  }
+
+  // For DCC++ classic compatibility, state reported to JMRI is 1 for thrown and 0 for closed
+  void ServoTurnout::print(Print *stream) {
+    StringFormatter::send(stream, F("<H %d SERVO %d %d %d %d %d>\n"), _turnoutData.id, _servoTurnoutData.vpin, 
+      _servoTurnoutData.thrownPosition, _servoTurnoutData.closedPosition, _servoTurnoutData.profile, 
+      !_turnoutData.closed);
+  }
+
+  // ServoTurnout-specific code for throwing or closing a servo turnout.
+  bool ServoTurnout::setClosedInternal(bool close) {
+#ifndef IO_NO_HAL
+    IODevice::writeAnalogue(_servoTurnoutData.vpin, 
+      close ? _servoTurnoutData.closedPosition : _servoTurnoutData.thrownPosition, _servoTurnoutData.profile);
+    _turnoutData.closed = close;
+#else
+    (void)close;  // avoid compiler warnings
+#endif
+    return true;
+  }
+
+  void ServoTurnout::save() {
+    // Write turnout definition and current position to EEPROM
+    // First write common servo data, then
+    // write the servo-specific data
+    EEPROM.put(EEStore::pointer(), _turnoutData);
+    EEStore::advance(sizeof(_turnoutData));
+    EEPROM.put(EEStore::pointer(), _servoTurnoutData);
+    EEStore::advance(sizeof(_servoTurnoutData));
+  }
+
+/*************************************************************************************
+ * DCCTurnout - Turnout controlled by DCC Accessory Controller.
+ * 
+ *************************************************************************************/
+
+#if defined(DCC_TURNOUTS_RCN_213)
+  const bool DCCTurnout::rcn213Compliant = true;
+#else
+  const bool DCCTurnout::rcn213Compliant = false;
 #endif
 
-Turnout *Turnout::firstTurnout=NULL;
-int Turnout::turnoutlistHash=0; //bump on every change so clients know when to refresh their lists
+  // DCCTurnoutData contains data specific to this subclass that is 
+  // written to EEPROM when the turnout is saved.
+  struct DCCTurnoutData {
+    // DCC address (Address in bits 15-2, subaddress in bits 1-0
+    uint16_t address; // CS currently supports linear address 1-2048
+      // That's DCC accessory address 1-512 and subaddress 0-3.
+  } _dccTurnoutData; // 2 bytes
+
+  // Constructor
+  DCCTurnout::DCCTurnout(uint16_t id, uint16_t address, uint8_t subAdd) :
+    Turnout(id, TURNOUT_DCC, false)
+  {
+    _dccTurnoutData.address = address;
+    _dccTurnoutData.subAddress = subAdd;
+  }
+
+  // Create function
+  /* static */ Turnout *DCCTurnout::create(uint16_t id, uint16_t add, uint8_t subAdd) {
+    Turnout *tt = get(id);
+    if (tt) { 
+      // Object already exists, check if it is usable
+      if (tt->isType(TURNOUT_DCC)) {
+        // Yes, so set parameters<T>
+        DCCTurnout *dt = (DCCTurnout *)tt;
+        dt->_dccTurnoutData.address = add;
+        dt->_dccTurnoutData.subAddress = subAdd;
+        // Don't touch the _closed parameter, retain the original value.
+        return tt;
+      } else {
+        // Incompatible object, delete and recreate
+        remove(id);
+      }
+    }
+    tt = (Turnout *)new DCCTurnout(id, add, subAdd);
+    return tt;
+  }
+
+  // Load a DCC turnout definition from EEPROM.  The common Turnout data has already been read at this point.
+  /* static */ Turnout *DCCTurnout::load(struct TurnoutData *turnoutData) {
+    DCCTurnoutData dccTurnoutData;
+    // Read class-specific data from EEPROM
+    EEPROM.get(EEStore::pointer(), dccTurnoutData);
+    EEStore::advance(sizeof(dccTurnoutData));
+    
+    // Create new object
+    DCCTurnout *tt = new DCCTurnout(turnoutData->id, dccTurnoutData.address, dccTurnoutData.subAddress);
+
+    return tt;
+  }
+
+  void DCCTurnout::print(Print *stream) {
+    StringFormatter::send(stream, F("<H %d DCC %d %d %d>\n"), _turnoutData.id, 
+      _dccTurnoutData.address, _dccTurnoutData.subAddress, !_turnoutData.closed); 
+    // Also report using classic DCC++ syntax for DCC accessory turnouts, since JMRI expects this.
+    StringFormatter::send(stream, F("<H %d %d %d %d>\n"), _turnoutData.id, 
+      _dccTurnoutData.address, _dccTurnoutData.subAddress, !_turnoutData.closed); 
+  }
+
+  bool DCCTurnout::setClosedInternal(bool close) {
+    // DCC++ Classic behaviour is that Throw writes a 1 in the packet,
+    // and Close writes a 0.  
+    // RCN-213 specifies that Throw is 0 and Close is 1.
+    DCC::setAccessory(_dccTurnoutData.address, _dccTurnoutData.subAddress, close ^ !rcn213Compliant);
+    _turnoutData.closed = close;
+    return true;
+  }
+
+  void DCCTurnout::save() {
+    // Write turnout definition and current position to EEPROM
+    // First write common servo data, then
+    // write the servo-specific data
+    EEPROM.put(EEStore::pointer(), _turnoutData);
+    EEStore::advance(sizeof(_turnoutData));
+    EEPROM.put(EEStore::pointer(), _dccTurnoutData);
+    EEStore::advance(sizeof(_dccTurnoutData));
+  }
+
+
+
+/*************************************************************************************
+ * VpinTurnout - Turnout controlled through a HAL vpin.
+ * 
+ *************************************************************************************/
+
+  // Constructor
+  VpinTurnout::VpinTurnout(uint16_t id, VPIN vpin, bool closed) :
+    Turnout(id, TURNOUT_VPIN, closed)
+  {
+    _vpinTurnoutData.vpin = vpin;
+  }
+
+  // Create function
+  /* static */ Turnout *VpinTurnout::create(uint16_t id, VPIN vpin, bool closed) {
+    Turnout *tt = get(id);
+    if (tt) { 
+      // Object already exists, check if it is usable
+      if (tt->isType(TURNOUT_VPIN)) {
+        // Yes, so set parameters
+        VpinTurnout *vt = (VpinTurnout *)tt;
+        vt->_vpinTurnoutData.vpin = vpin;
+        // Don't touch the _closed parameter, retain the original value.
+        return tt;
+      } else {
+        // Incompatible object, delete and recreate
+        remove(id);
+      }
+    }
+    tt = (Turnout *)new VpinTurnout(id, vpin, closed);
+    return tt;
+  }
+
+  // Load a VPIN turnout definition from EEPROM.  The common Turnout data has already been read at this point.
+  /* static */ Turnout *VpinTurnout::load(struct TurnoutData *turnoutData) {
+    VpinTurnoutData vpinTurnoutData;
+    // Read class-specific data from EEPROM
+    EEPROM.get(EEStore::pointer(), vpinTurnoutData);
+    EEStore::advance(sizeof(vpinTurnoutData));
+    
+    // Create new object
+    VpinTurnout *tt = new VpinTurnout(turnoutData->id, vpinTurnoutData.vpin, turnoutData->closed);
+
+    return tt;
+  }
+
+  // Report 1 for thrown, 0 for closed.
+  void VpinTurnout::print(Print *stream) {
+    StringFormatter::send(stream, F("<H %d VPIN %d %d>\n"), _turnoutData.id, _vpinTurnoutData.vpin, 
+      !_turnoutData.closed); 
+  }
+
+  bool VpinTurnout::setClosedInternal(bool close) {
+    IODevice::write(_vpinTurnoutData.vpin, close);
+    _turnoutData.closed = close;
+    return true;
+  }
+
+  void VpinTurnout::save() {
+    // Write turnout definition and current position to EEPROM
+    // First write common servo data, then
+    // write the servo-specific data
+    EEPROM.put(EEStore::pointer(), _turnoutData);
+    EEStore::advance(sizeof(_turnoutData));
+    EEPROM.put(EEStore::pointer(), _vpinTurnoutData);
+    EEStore::advance(sizeof(_vpinTurnoutData));
+  }
+
+
+/*************************************************************************************
+ * LCNTurnout - Turnout controlled by Loconet
+ * 
+ *************************************************************************************/
+
+  // LCNTurnout has no specific data, and in any case is not written to EEPROM!
+  // struct LCNTurnoutData {
+  // } _lcnTurnoutData; // 0 bytes
+
+  // Constructor
+  LCNTurnout::LCNTurnout(uint16_t id, bool closed) :
+    Turnout(id, TURNOUT_LCN, closed)
+  { }
+
+  // Create function
+  /* static */ Turnout *LCNTurnout::create(uint16_t id, bool closed) {
+    Turnout *tt = get(id);
+    if (tt) { 
+      // Object already exists, check if it is usable
+      if (tt->isType(TURNOUT_LCN)) {
+        // Yes, so return this object
+        return tt;
+      } else {
+        // Incompatible object, delete and recreate
+        remove(id);
+      }
+    }
+    tt = (Turnout *)new LCNTurnout(id, closed);
+    return tt;
+  }
+
+  bool LCNTurnout::setClosedInternal(bool close) {
+    // Assume that the LCN command still uses 1 for throw and 0 for close...
+    LCN::send('T', _turnoutData.id, !close);
+    // The _turnoutData.closed flag should be updated by a message from the LCN master, later.
+    return true;
+  }
+
+  // LCN turnouts not saved to EEPROM.
+  //void save() override {  }
+  //static Turnout *load(struct TurnoutData *turnoutData) {
+
+  // Report 1 for thrown, 0 for closed.
+  void LCNTurnout::print(Print *stream) {
+    StringFormatter::send(stream, F("<H %d LCN %d>\n"), _turnoutData.id, 
+    !_turnoutData.closed); 
+  }
+

Turnouts.h

@@ -1,4 +1,6 @@
 /*
+ *  © 2021 Restructured Neil McKechnie
+ *  © 2013-2016 Gregg E. Berman
  *  © 2020, Chris Harlow. All rights reserved.
  *  
  *  This file is part of Asbelos DCC API
@@ -16,42 +18,283 @@
  *  You should have received a copy of the GNU General Public License
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
-#ifndef Turnouts_h
-#define Turnouts_h
 
-#include <Arduino.h>
-#include "DCC.h"
+#ifndef TURNOUTS_H
+#define TURNOUTS_H
 
-const byte STATUS_ACTIVE=0x80; // Flag as activated
-const byte STATUS_PWM=0x40; // Flag as a PWM turnout
-const byte STATUS_PWMPIN=0x3F; // PWM  pin 0-63
+//#define EESTOREDEBUG 
+#include "Arduino.h"
+#include "IODevice.h"
 
-struct TurnoutData {
-   int id;
-   uint8_t tStatus; // has STATUS_ACTIVE, STATUS_PWM, STATUS_PWMPIN  
-   union {uint8_t subAddress; char moveAngle;}; //DCC  sub addrerss or PWM difference from inactiveAngle  
-   union {int address; int inactiveAngle;}; // DCC address or PWM servo angle 
+
+// Turnout type definitions
+enum {
+  TURNOUT_DCC = 1,
+  TURNOUT_SERVO = 2,
+  TURNOUT_VPIN = 3,
+  TURNOUT_LCN = 4,
 };
 
+/*************************************************************************************
+ * Turnout - Base class for turnouts.
+ * 
+ *************************************************************************************/
+
 class Turnout {
-  public:
-  static Turnout *firstTurnout;
-  static int turnoutlistHash;
-  TurnoutData data;
-  Turnout *nextTurnout;
-  static  bool activate(int n, bool state);
-  static Turnout* get(int);
-  static bool remove(int);
-  static bool isActive(int);
-  static void load();
-  static void store();
-  static Turnout *create(int id , int address , int subAddress);
-  static Turnout *create(int id , byte pin , int activeAngle, int inactiveAngle);
-  static Turnout *create(int id);
-  void activate(bool state);
-#ifdef EESTOREDEBUG
-  void print(Turnout *tt);
-#endif
-}; // Turnout
+protected:
+  /* 
+   * Object data
+   */
+
+  // The TurnoutData struct contains data common to all turnout types, that 
+  // is written to EEPROM when the turnout is saved.
+  // The first byte of this struct contains the 'closed' flag which is
+  // updated whenever the turnout changes from thrown to closed and
+  // vice versa.  If the turnout has been saved, then this byte is rewritten
+  // when changed in RAM.  The 'closed' flag must be located in the first byte.
+  struct TurnoutData {
+    union {
+      struct {
+        bool closed : 1;
+        bool _rfu: 2;
+        uint8_t turnoutType : 5;
+      };
+      uint8_t flags;
+    };
+    uint16_t id;
+  } _turnoutData;  // 3 bytes
+
+  // Address in eeprom of first byte of the _turnoutData struct (containing the closed flag).
+  // Set to zero if the object has not been saved in EEPROM, e.g. for newly created Turnouts, and 
+  // for all LCN turnouts.
+  uint16_t _eepromAddress = 0;
+
+  // Pointer to next turnout on linked list.
+  Turnout *_nextTurnout = 0;
+
+  /*
+   * Constructor
+   */
+  Turnout(uint16_t id, uint8_t turnoutType, bool closed) {
+    _turnoutData.id = id;
+    _turnoutData.turnoutType = turnoutType;
+    _turnoutData.closed = closed;
+    add(this);
+  }
+
+  /* 
+   * Static data
+   */ 
+
+  static Turnout *_firstTurnout;
+  static int _turnoutlistHash;
+
+  /* 
+   * Virtual functions
+   */
+
+  virtual bool setClosedInternal(bool close) = 0;  // Mandatory in subclass
+  virtual void save() {}
   
+  /*
+   * Static functions
+   */
+
+  static Turnout *get(uint16_t id);
+
+  static void add(Turnout *tt);
+  
+public:
+  /* 
+   * Static data
+   */
+  static int turnoutlistHash;
+  static const bool useClassicTurnoutCommands;
+  
+  /*
+   * Public base class functions
+   */
+  inline bool isClosed() { return _turnoutData.closed; };
+  inline bool isThrown() { return !_turnoutData.closed; }
+  inline bool isType(uint8_t type) { return _turnoutData.turnoutType == type; }
+  inline uint16_t getId() { return _turnoutData.id; }
+  inline Turnout *next() { return _nextTurnout; }
+  void printState(Print *stream);
+  /* 
+   * Virtual functions
+   */
+  virtual void print(Print *stream) {
+    (void)stream;  // avoid compiler warnings.
+  }
+  virtual ~Turnout() {}   // Destructor
+
+  /*
+   * Public static functions
+   */
+  inline static bool exists(uint16_t id) { return get(id) != 0; }
+
+  static bool remove(uint16_t id);
+
+  static bool isClosed(uint16_t id);
+
+  inline static bool isThrown(uint16_t id) {
+    return !isClosed(id);
+  }
+
+  static bool setClosed(uint16_t id, bool closeFlag);
+
+  inline static bool setClosed(uint16_t id) {
+    return setClosed(id, true);
+  }
+
+  inline static bool setThrown(uint16_t id) {
+    return setClosed(id, false);
+  }
+
+  static bool setClosedStateOnly(uint16_t id, bool close);
+
+  inline static Turnout *first() { return _firstTurnout; }
+
+  // Load all turnout definitions.
+  static void load();
+  // Load one turnout definition
+  static Turnout *loadTurnout();
+  // Save all turnout definitions
+  static void store();
+
+  static void printAll(Print *stream) {
+    for (Turnout *tt = _firstTurnout; tt != 0; tt = tt->_nextTurnout)
+      tt->printState(stream);
+  }
+
+  static void printState(uint16_t id, Print *stream);
+};
+
+
+/*************************************************************************************
+ * ServoTurnout - Turnout controlled by servo device.
+ * 
+ *************************************************************************************/
+class ServoTurnout : public Turnout {
+private:
+  // ServoTurnoutData contains data specific to this subclass that is 
+  // written to EEPROM when the turnout is saved.
+  struct ServoTurnoutData {
+    VPIN vpin;
+    uint16_t closedPosition : 12;
+    uint16_t thrownPosition : 12;
+    uint8_t profile;
+  } _servoTurnoutData; // 6 bytes
+
+  // Constructor
+  ServoTurnout(uint16_t id, VPIN vpin, uint16_t thrownPosition, uint16_t closedPosition, uint8_t profile, bool closed);
+
+public:
+  // Create function
+  static Turnout *create(uint16_t id, VPIN vpin, uint16_t thrownPosition, uint16_t closedPosition, uint8_t profile, bool closed=true);
+
+  // Load a Servo turnout definition from EEPROM.  The common Turnout data has already been read at this point.
+  static Turnout *load(struct TurnoutData *turnoutData);
+  void print(Print *stream) override;
+
+protected:
+  // ServoTurnout-specific code for throwing or closing a servo turnout.
+  bool setClosedInternal(bool close) override;
+  void save() override;
+
+};
+
+/*************************************************************************************
+ * DCCTurnout - Turnout controlled by DCC Accessory Controller.
+ * 
+ *************************************************************************************/
+class DCCTurnout : public Turnout {
+private:
+  // DCCTurnoutData contains data specific to this subclass that is 
+  // written to EEPROM when the turnout is saved.
+  struct DCCTurnoutData {
+    // DCC address (Address in bits 15-2, subaddress in bits 1-0)
+    struct {
+      uint16_t address : 14;
+      uint8_t subAddress : 2;
+    };
+  } _dccTurnoutData; // 2 bytes
+
+  // Constructor
+  DCCTurnout(uint16_t id, uint16_t address, uint8_t subAdd);
+
+public:
+  // Create function
+  static Turnout *create(uint16_t id, uint16_t add, uint8_t subAdd);
+  // Load a VPIN turnout definition from EEPROM.  The common Turnout data has already been read at this point.
+  static Turnout *load(struct TurnoutData *turnoutData);
+  void print(Print *stream) override;
+  // Flag whether DCC Accessory packets are to contain 1=close/0=throw(RCN-213) or 1=throw/0-close (DCC++ Classic)
+  static const bool rcn213Compliant;
+
+protected:
+  bool setClosedInternal(bool close) override;
+  void save() override;
+
+};
+
+
+/*************************************************************************************
+ * VpinTurnout - Turnout controlled through a HAL vpin.
+ * 
+ *************************************************************************************/
+class VpinTurnout : public Turnout {
+private:
+  // VpinTurnoutData contains data specific to this subclass that is 
+  // written to EEPROM when the turnout is saved.
+  struct VpinTurnoutData {
+    VPIN vpin;
+  } _vpinTurnoutData; // 2 bytes
+
+  // Constructor
+ VpinTurnout(uint16_t id, VPIN vpin, bool closed);
+
+public:
+  // Create function
+  static Turnout *create(uint16_t id, VPIN vpin, bool closed=true);
+
+  // Load a VPIN turnout definition from EEPROM.  The common Turnout data has already been read at this point.
+  static Turnout *load(struct TurnoutData *turnoutData);
+  void print(Print *stream) override;
+
+protected:
+  bool setClosedInternal(bool close) override;
+  void save() override;
+
+};
+
+
+/*************************************************************************************
+ * LCNTurnout - Turnout controlled by Loconet
+ * 
+ *************************************************************************************/
+class LCNTurnout : public Turnout {
+private:
+  // LCNTurnout has no specific data, and in any case is not written to EEPROM!
+  // struct LCNTurnoutData {
+  // } _lcnTurnoutData; // 0 bytes
+
+  // Constructor 
+  LCNTurnout(uint16_t id, bool closed);
+
+public:
+  // Create function
+  static Turnout *create(uint16_t id, bool closed=true);
+
+
+  bool setClosedInternal(bool close) override;
+
+  // LCN turnouts not saved to EEPROM.
+  //void save() override {  }
+  //static Turnout *load(struct TurnoutData *turnoutData) {
+
+  void print(Print *stream) override;
+
+};
+
 #endif

VirtualTimer.h

@@ -1,21 +0,0 @@
-// This file is copied from https://github.com/davidcutting42/ArduinoTimers
-// All Credit to David Cutting
-
-#ifndef VirtualTimer_h
-#define VirtualTimer_h
-
-class VirtualTimer
-{
-public:
-    virtual void initialize() = 0;
-    virtual void setPeriod(unsigned long microseconds) = 0;
-    virtual void start() = 0;
-	virtual void stop() = 0;
-
-    virtual void attachInterrupt(void (*isr)()) = 0;
-    virtual void detachInterrupt() = 0;
-private:
-
-};
-
-#endif

WiThrottle.cpp

@@ -40,6 +40,7 @@
  *  WiThrottle.h sets the max locos per client at 10, this is ok to increase but requires just an extra 3 bytes per loco per client.      
 */
 #include <Arduino.h>
+#include "defines.h"
 #include "WiThrottle.h"
 #include "DCC.h"
 #include "DCCWaveform.h"
@@ -48,12 +49,13 @@
 #include "DIAG.h"
 #include "GITHUB_SHA.h"
 #include "version.h"
+#include "RMFT2.h"
+
 
 #define LOOPLOCOS(THROTTLECHAR, CAB)  for (int loco=0;loco<MAX_MY_LOCO;loco++) \
       if ((myLocos[loco].throttle==THROTTLECHAR || '*'==THROTTLECHAR) && (CAB<0 || myLocos[loco].cab==CAB))
 
 WiThrottle * WiThrottle::firstThrottle=NULL;
-bool WiThrottle::annotateLeftRight=false;
 
 WiThrottle* WiThrottle::getThrottle( int wifiClient) {
   for (WiThrottle* wt=firstThrottle; wt!=NULL ; wt=wt->nextThrottle)  
@@ -76,13 +78,15 @@ bool WiThrottle::areYouUsingThrottle(int cab) {
  // One instance of WiThrottle per connected client, so we know what the locos are 
  
 WiThrottle::WiThrottle( int wificlientid) {
-   if (Diag::WITHROTTLE) DIAG(F("\n%l Creating new WiThrottle for client %d\n"),millis(),wificlientid); 
+   if (Diag::WITHROTTLE) DIAG(F("%l Creating new WiThrottle for client %d"),millis(),wificlientid); 
    nextThrottle=firstThrottle;
    firstThrottle= this;
    clientid=wificlientid;
    initSent=false; // prevent sending heartbeats before connection completed
    heartBeatEnable=false; // until client turns it on
    turnoutListHash = -1;  // make sure turnout list is sent once
+   exRailSent=false;
+   mostRecentCab=0;                
    for (int loco=0;loco<MAX_MY_LOCO; loco++) myLocos[loco].throttle='\0';
 }
 
@@ -104,7 +108,7 @@ void WiThrottle::parse(RingStream * stream, byte * cmdx) {
   byte * cmd=cmdx;
   
   heartBeat=millis();
-  if (Diag::WITHROTTLE) DIAG(F("\n%l WiThrottle(%d)<-[%e]\n"),millis(),clientid,cmd);
+  if (Diag::WITHROTTLE) DIAG(F("%l WiThrottle(%d)<-[%e]"),millis(),clientid,cmd);
 
   if (initSent) {
     // Send power state if different than last sent
@@ -116,12 +120,21 @@ void WiThrottle::parse(RingStream * stream, byte * cmdx) {
     // Send turnout list if changed since last sent (will replace list on client)
     if (turnoutListHash != Turnout::turnoutlistHash) {
       StringFormatter::send(stream,F("PTL"));
-      for(Turnout *tt=Turnout::firstTurnout;tt!=NULL;tt=tt->nextTurnout){
-          StringFormatter::send(stream,F("]\\[%d}|{%d}|{%c"), tt->data.id, tt->data.id, Turnout::isActive(tt->data.id)?'4':'2');
+      for(Turnout *tt=Turnout::first();tt!=NULL;tt=tt->next()){
+          int id=tt->getId();
+          StringFormatter::send(stream,F("]\\[%d}|{%d}|{%c"), id, id, Turnout::isClosed(id)?'2':'4');
       }
       StringFormatter::send(stream,F("\n"));
       turnoutListHash = Turnout::turnoutlistHash; // keep a copy of hash for later comparison
     }
+
+    else if (!exRailSent) {
+      // Send ExRail routes list if not already sent (but not at same time as turnouts above)
+      exRailSent=true;
+#ifdef RMFT_ACTIVE
+      RMFT2::emitWithrottleRouteList(stream);
+#endif    
+    }
   }
 
    while (cmd[0]) {
@@ -133,28 +146,45 @@ void WiThrottle::parse(RingStream * stream, byte * cmdx) {
        case 'P':  
             if (cmd[1]=='P' && cmd[2]=='A' )  {  //PPA power mode 
               DCCWaveform::mainTrack.setPowerMode(cmd[3]=='1'?POWERMODE::ON:POWERMODE::OFF);
+	      if (MotorDriver::commonFaultPin) // commonFaultPin prevents individual track handling
+		DCCWaveform::progTrack.setPowerMode(cmd[3]=='1'?POWERMODE::ON:POWERMODE::OFF);
               StringFormatter::send(stream,F("PPA%x\n"),DCCWaveform::mainTrack.getPowerMode()==POWERMODE::ON);
               lastPowerState = (DCCWaveform::mainTrack.getPowerMode()==POWERMODE::ON); //remember power state sent for comparison later
             }
+#if defined(RMFT_ACTIVE)
+            else if (cmd[1]=='R' && cmd[2]=='A' && cmd[3]=='2' ) { // Route activate
+              // exrail routes are RA2Rn , Animations are RA2An 
+              int route=getInt(cmd+5);
+              uint16_t cab=cmd[4]=='A' ? mostRecentCab : 0; 
+              RMFT2::createNewTask(route, cab);
+            }
+#endif    
             else if (cmd[1]=='T' && cmd[2]=='A') { // PTA accessory toggle 
                 int id=getInt(cmd+4); 
-                bool newstate=false;
-                Turnout * tt=Turnout::get(id);
-                if (!tt) {
+                if (!Turnout::exists(id)) {
                   // If turnout does not exist, create it
                   int addr = ((id - 1) / 4) + 1;
                   int subaddr = (id - 1) % 4;
-                  Turnout::create(id,addr,subaddr);
+                  DCCTurnout::create(id,addr,subaddr);
                   StringFormatter::send(stream, F("HmTurnout %d created\n"),id);
                 }
                 switch (cmd[3]) {
-                    case 'T': newstate=true; break;
-                    case 'C': newstate=false; break;
-                    case '2': newstate=!Turnout::isActive(id);                 
+            		  // T and C according to RCN-213 where 0 is Stop, Red, Thrown, Diverging.
+            		  case 'T': 
+            		     Turnout::setClosed(id,false);
+                     break;
+            		  case 'C': 
+                     Turnout::setClosed(id,true);
+                     break;
+            		  case '2': 
+            		     Turnout::setClosed(id,!Turnout::isClosed(id));
+                     break;
+            		  default :
+            		     Turnout::setClosed(id,true);
+                     break;
                 }
-		            Turnout::activate(id,newstate);
-                StringFormatter::send(stream, F("PTA%c%d\n"),newstate?'4':'2',id );   
-            }
+		            StringFormatter::send(stream, F("PTA%c%d\n"),Turnout::isClosed(id)?'2':'4',id );
+		        }
             break;
        case 'N':  // Heartbeat (2), only send if connection completed by 'HU' message
             if (initSent) { 
@@ -168,8 +198,7 @@ void WiThrottle::parse(RingStream * stream, byte * cmdx) {
             if (cmd[1] == 'U') {
               StringFormatter::send(stream,F("VN2.0\nHTDCC-EX\nRL0\n"));
               StringFormatter::send(stream,F("HtDCC-EX v%S, %S, %S, %S\n"), F(VERSION), F(ARDUINO_TYPE), DCC::getMotorShieldName(), F(GITHUB_SHA));
-              if (annotateLeftRight) StringFormatter::send(stream,F("PTT]\\[Turnouts}|{Turnout]\\[Left}|{2]\\[Right}|{4\n"));
-              else                   StringFormatter::send(stream,F("PTT]\\[Turnouts}|{Turnout]\\[Closed}|{2]\\[Thrown}|{4\n"));
+              StringFormatter::send(stream,F("PTT]\\[Turnouts}|{Turnout]\\[THROW}|{2]\\[CLOSE}|{4\n"));
               StringFormatter::send(stream,F("PPA%x\n"),DCCWaveform::mainTrack.getPowerMode()==POWERMODE::ON);
               lastPowerState = (DCCWaveform::mainTrack.getPowerMode()==POWERMODE::ON); //remember power state sent for comparison later
               StringFormatter::send(stream,F("*%d\n"),HEARTBEAT_SECONDS);
@@ -182,7 +211,7 @@ void WiThrottle::parse(RingStream * stream, byte * cmdx) {
                 StringFormatter::send(stream, F("M%c-%c%d<;>\n"), myLocos[loco].throttle, LorS(myLocos[loco].cab), myLocos[loco].cab);
               }
             }
-            if (Diag::WITHROTTLE) DIAG(F("%l WiThrottle(%d) Quit\n"),millis(),clientid);
+            if (Diag::WITHROTTLE) DIAG(F("%l WiThrottle(%d) Quit"),millis(),clientid);
             delete this; 
             break;           
    }
@@ -205,6 +234,7 @@ int WiThrottle::getLocoId(byte * cmd) {
     if (cmd[0]!='L' && cmd[0]!='S') return 0; // should not match any locos
     return getInt(cmd+1); 
 }
+
 void WiThrottle::multithrottle(RingStream * stream, byte * cmd){ 
           char throttleChar=cmd[1];
           int locoid=getLocoId(cmd+3); // -1 for *
@@ -212,9 +242,20 @@ void WiThrottle::multithrottle(RingStream * stream, byte * cmd){
           while(*aval !=';' && *aval !='\0') aval++;
           if (*aval) aval+=2;  // skip ;>
 
-//       DIAG(F("\nMultithrottle aval=%c cab=%d"), aval[0],locoid);    
+//       DIAG(F("Multithrottle aval=%c cab=%d"), aval[0],locoid);    
        switch(cmd[2]) {
           case '+':  // add loco request
+                if (cmd[3]=='*') { 
+                  // M+* means get loco from prog track, then join tracks ready to drive away
+                  // Stash the things the callback will need later
+                  stashStream= stream;
+                  stashClient=stream->peekTargetMark();
+                  stashThrottleChar=throttleChar;
+                  stashInstance=this;
+                  // ask DCC to call us back when the loco id has been read
+                  DCC::getLocoId(getLocoCallback); // will remove any previous join                    
+                  return; // return nothing in stream as response is sent later in the callback 
+                }
                 //return error if address zero requested
                 if (locoid==0) { 
                   StringFormatter::send(stream, F("HMAddress '0' not supported!\n"), cmd[3] ,locoid);                    
@@ -230,11 +271,12 @@ void WiThrottle::multithrottle(RingStream * stream, byte * cmd){
                   if (myLocos[loco].throttle=='\0') { 
                     myLocos[loco].throttle=throttleChar;
                     myLocos[loco].cab=locoid;
+                    mostRecentCab=locoid;
                     StringFormatter::send(stream, F("M%c+%c%d<;>\n"), throttleChar, cmd[3] ,locoid); //tell client to add loco
                     //Get known Fn states from DCC 
                     for(int fKey=0; fKey<=28; fKey++) { 
                       int fstate=DCC::getFn(locoid,fKey);
-                      if (fstate>=0) StringFormatter::send(stream,F("M%cA%c<;>F%d%d\n"),throttleChar,cmd[3],fstate,fKey);
+                        if (fstate>=0) StringFormatter::send(stream,F("M%cA%c%d<;>F%d%d\n"),throttleChar,cmd[3],locoid,fstate,fKey);                     
                     }
                     StringFormatter::send(stream, F("M%cA%c%d<;>V%d\n"), throttleChar, cmd[3], locoid, DCCToWiTSpeed(DCC::getThrottleSpeed(locoid)));
                     StringFormatter::send(stream, F("M%cA%c%d<;>R%d\n"), throttleChar, cmd[3], locoid, DCC::getThrottleDirection(locoid));
@@ -258,14 +300,15 @@ void WiThrottle::multithrottle(RingStream * stream, byte * cmd){
 
 void WiThrottle::locoAction(RingStream * stream, byte* aval, char throttleChar, int cab){
     // Note cab=-1 for all cabs in the consist called throttleChar.  
-//    DIAG(F("\nLoco Action aval=%c%c throttleChar=%c, cab=%d"), aval[0],aval[1],throttleChar, cab);
+//    DIAG(F("Loco Action aval=%c%c throttleChar=%c, cab=%d"), aval[0],aval[1],throttleChar, cab);
      switch (aval[0]) {
            case 'V':  // Vspeed
              { 
-              byte locospeed=WiTToDCCSpeed(getInt(aval+1));
+              int witSpeed=getInt(aval+1);
               LOOPLOCOS(throttleChar, cab) {
-                DCC::setThrottle(myLocos[loco].cab, locospeed, DCC::getThrottleDirection(myLocos[loco].cab));
-                StringFormatter::send(stream,F("M%cA%c%d<;>V%d\n"), throttleChar, LorS(myLocos[loco].cab), myLocos[loco].cab, locospeed);
+                mostRecentCab=myLocos[loco].cab;
+                DCC::setThrottle(myLocos[loco].cab, WiTToDCCSpeed(witSpeed), DCC::getThrottleDirection(myLocos[loco].cab));
+                StringFormatter::send(stream,F("M%cA%c%d<;>V%d\n"), throttleChar, LorS(myLocos[loco].cab), myLocos[loco].cab, witSpeed);
                 }
              } 
             break;
@@ -297,7 +340,8 @@ void WiThrottle::locoAction(RingStream * stream, byte* aval, char throttleChar,
             case 'R':
             { 
               bool forward=aval[1]!='0';
-              LOOPLOCOS(throttleChar, cab) {              
+              LOOPLOCOS(throttleChar, cab) {
+                mostRecentCab=myLocos[loco].cab;
                 DCC::setThrottle(myLocos[loco].cab, DCC::getThrottleSpeed(myLocos[loco].cab), forward);
                 StringFormatter::send(stream,F("M%cA%c%d<;>R%d\n"), throttleChar, LorS(myLocos[loco].cab), myLocos[loco].cab, forward);
               }
@@ -313,6 +357,7 @@ void WiThrottle::locoAction(RingStream * stream, byte* aval, char throttleChar,
             case 'I': // Idle, set speed to 0
             case 'Q': // Quit, set speed to 0
               LOOPLOCOS(throttleChar, cab) {
+                mostRecentCab=myLocos[loco].cab;
                 DCC::setThrottle(myLocos[loco].cab, 0, DCC::getThrottleDirection(myLocos[loco].cab));
                 StringFormatter::send(stream,F("M%cA%c%d<;>V%d\n"), throttleChar, LorS(myLocos[loco].cab), myLocos[loco].cab, 0);
               }
@@ -352,10 +397,10 @@ void WiThrottle::loop(RingStream * stream) {
 void WiThrottle::checkHeartbeat() {
   // if eStop time passed... eStop any locos still assigned to this client and then drop the connection
   if(heartBeatEnable && (millis()-heartBeat > ESTOP_SECONDS*1000)) {
-  if (Diag::WITHROTTLE)  DIAG(F("\n\n%l WiThrottle(%d) eStop(%ds) timeout, drop connection\n"), millis(), clientid, ESTOP_SECONDS);
+  if (Diag::WITHROTTLE)  DIAG(F("%l WiThrottle(%d) eStop(%ds) timeout, drop connection"), millis(), clientid, ESTOP_SECONDS);
     LOOPLOCOS('*', -1) { 
       if (myLocos[loco].throttle!='\0') {
-        if (Diag::WITHROTTLE) DIAG(F("%l  eStopping cab %d\n"),millis(),myLocos[loco].cab);
+        if (Diag::WITHROTTLE) DIAG(F("%l  eStopping cab %d"),millis(),myLocos[loco].cab);
         DCC::setThrottle(myLocos[loco].cab, 1, DCC::getThrottleDirection(myLocos[loco].cab)); // speed 1 is eStop
       }
     }
@@ -365,4 +410,24 @@ void WiThrottle::checkHeartbeat() {
 
 char WiThrottle::LorS(int cab) {
     return (cab<127)?'S':'L';
-} 
+}
+
+// Drive Away feature. Callback handling
+ 
+RingStream * WiThrottle::stashStream;
+WiThrottle * WiThrottle::stashInstance;
+byte         WiThrottle::stashClient;
+char         WiThrottle::stashThrottleChar;
+
+void WiThrottle::getLocoCallback(int16_t locoid) {
+  stashStream->mark(stashClient);
+  if (locoid<0) StringFormatter::send(stashStream,F("HMNo loco found on prog track\n"));
+  else {
+    char addcmd[20]={'M',stashThrottleChar,'+',LorS(locoid) };
+    itoa(locoid,addcmd+4,10);
+    stashInstance->multithrottle(stashStream, (byte *)addcmd);
+    DCCWaveform::progTrack.setPowerMode(POWERMODE::ON);
+    DCC::setProgTrackSyncMain(true);  // <1 JOIN> so we can drive loco away
+  }
+  stashStream->commit();
+}

WiThrottle.h

@@ -31,7 +31,7 @@ class WiThrottle {
     static void loop(RingStream * stream);
     void parse(RingStream * stream, byte * cmd);
     static WiThrottle* getThrottle( int wifiClient); 
-    static bool annotateLeftRight;
+    
   private: 
     WiThrottle( int wifiClientId);
     ~WiThrottle();
@@ -53,6 +53,8 @@ class WiThrottle {
       bool heartBeatEnable;
       unsigned long heartBeat;
       bool initSent; // valid connection established
+      bool exRailSent; // valid connection established
+      uint16_t mostRecentCab;
       int turnoutListHash;  // used to check for changes to turnout list
       bool lastPowerState;  // last power state sent to this client
       int DCCToWiTSpeed(int DCCSpeed);
@@ -60,6 +62,14 @@ class WiThrottle {
       void multithrottle(RingStream * stream, byte * cmd);
       void locoAction(RingStream * stream, byte* aval, char throttleChar, int cab);
       void accessory(RingStream *, byte* cmd);
-      void checkHeartbeat();  
+      void checkHeartbeat(); 
+
+       // callback stuff to support prog track acquire
+       static RingStream * stashStream;
+       static WiThrottle * stashInstance;
+       static byte         stashClient;
+       static char         stashThrottleChar;
+       static void         getLocoCallback(int16_t locoid);
+
 };
 #endif

WifiESP32.cpp

@@ -0,0 +1,246 @@
+/*
+    © 2021, Harald Barth.
+
+    This file is part of CommandStation-EX
+
+    This is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    It is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <vector>
+#include "defines.h"
+#if defined(ARDUINO_ARCH_ESP32)
+#include <WiFi.h>
+#include "WifiESP32.h"
+#include "DIAG.h"
+#include "RingStream.h"
+#include "CommandDistributor.h"
+/*
+#include "soc/rtc_wdt.h"
+#include "esp_task_wdt.h"
+*/
+
+#include "soc/timer_group_struct.h"
+#include "soc/timer_group_reg.h"
+void feedTheDog0(){
+  // feed dog 0
+  TIMERG0.wdt_wprotect=TIMG_WDT_WKEY_VALUE; // write enable
+  TIMERG0.wdt_feed=1;                       // feed dog
+  TIMERG0.wdt_wprotect=0;                   // write protect
+  // feed dog 1
+  //TIMERG1.wdt_wprotect=TIMG_WDT_WKEY_VALUE; // write enable
+  //TIMERG1.wdt_feed=1;                       // feed dog
+  //TIMERG1.wdt_wprotect=0;                   // write protect
+}
+
+/*
+void enableCoreWDT(byte core){
+  TaskHandle_t idle = xTaskGetIdleTaskHandleForCPU(core);
+  if(idle == NULL){
+    DIAG(F("Get idle rask on core %d failed"),core);
+  } else {
+    if(esp_task_wdt_add(idle) != ESP_OK){
+      DIAG(F("Failed to add Core %d IDLE task to WDT"),core);
+    } else {
+      DIAG(F("Added Core %d IDLE task to WDT"),core);
+    }
+  }
+}
+
+void disableCoreWDT(byte core){
+    TaskHandle_t idle = xTaskGetIdleTaskHandleForCPU(core);
+    if(idle == NULL || esp_task_wdt_delete(idle) != ESP_OK){
+      DIAG(F("Failed to remove Core %d IDLE task from WDT"),core);
+    }
+}
+*/
+
+static std::vector<WiFiClient> clients; // a list to hold all clients
+static WiFiServer *server = NULL;
+static RingStream *outboundRing = new RingStream(2048);
+static bool APmode = false;
+
+void wifiLoop(void *){
+  for(;;){
+    WifiESP::loop();
+  }
+}
+
+bool WifiESP::setup(const char *SSid,
+                    const char *password,
+                    const char *hostname,
+                    int port,
+                    const byte channel) {
+  bool havePassword = true;
+  bool haveSSID = true;
+  bool wifiUp = false;
+  uint8_t tries = 40;
+
+  // tests
+  //  enableCoreWDT(1);
+  //  disableCoreWDT(0);
+
+  const char *yourNetwork = "Your network ";
+  if (strncmp(yourNetwork, SSid, 13) == 0 || strncmp("", SSid, 13) == 0)
+    haveSSID = false;
+  if (strncmp(yourNetwork, password, 13) == 0 || strncmp("", password, 13) == 0)
+    havePassword = false;
+
+  if (haveSSID && havePassword) {
+    WiFi.mode(WIFI_STA);
+    WiFi.setAutoReconnect(true);
+    WiFi.begin(SSid, password);
+    while (WiFi.status() != WL_CONNECTED && tries) {
+      Serial.print('.');
+      tries--;
+      delay(500);
+    }
+    if (WiFi.status() == WL_CONNECTED) {
+      DIAG(F("Wifi STA IP %s"),WiFi.localIP().toString().c_str());
+      wifiUp = true;
+    } else {
+      DIAG(F("Could not connect to Wifi SSID %s"),SSid);
+    }
+  }
+  if (!haveSSID) {
+    // prepare all strings
+    String strSSID("DCC_");
+    String strPass("PASS_");
+    String strMac = WiFi.macAddress();
+    strMac.remove(0,9);
+    strMac.replace(":","");
+    strMac.replace(":","");
+    strSSID.concat(strMac);
+    strPass.concat(strMac);
+
+    WiFi.mode(WIFI_AP);
+    if (WiFi.softAP(strSSID.c_str(),
+		    havePassword ? password : strPass.c_str(),
+		    channel, false, 8)) {
+      DIAG(F("Wifi AP SSID %s PASS %s"),strSSID.c_str(),havePassword ? password : strPass.c_str());
+      DIAG(F("Wifi AP IP %s"),WiFi.softAPIP().toString().c_str());
+      wifiUp = true;
+      APmode = true;
+    } else {
+      DIAG(F("Could not set up AP with Wifi SSID %s"),strSSID.c_str());
+    }
+  }
+
+
+  if (!wifiUp) {
+    DIAG(F("Wifi setup all fail (STA and AP mode)"));
+    // no idea to go on
+    return false;
+  }
+  server = new WiFiServer(port); // start listening on tcp port
+  server->begin();
+  // server started here
+
+  //start loop task
+  if (pdPASS != xTaskCreatePinnedToCore(
+	wifiLoop, /* Task function. */
+	"wifiLoop",/* name of task.  */
+	10000,     /* Stack size of task */
+	NULL,      /* parameter of the task */
+	1,         /* priority of the task */
+	NULL,      /* Task handle to keep track of created task */
+	0)) {      /* pin task to core 0 */
+    DIAG(F("Could not create wifiLoop task"));
+    return false;
+  }
+
+  // report server started after wifiLoop creation
+  // when everything looks good
+  DIAG(F("Server up port %d"),port);
+  return true;
+}
+
+void WifiESP::loop() {
+  int clientId; //tmp loop var
+
+  // really no good way to check for LISTEN especially in AP mode?
+  if (APmode || WiFi.status() == WL_CONNECTED) {
+    if (server->hasClient()) {
+      // loop over all clients and remove inactive
+      for (clientId=0; clientId<clients.size(); clientId++){
+	// check if client is there and alive
+	if(!clients[clientId].connected()) {
+	  clients[clientId].stop();
+	  clients.erase(clients.begin()+clientId);
+	}
+      }
+      WiFiClient client;
+      while (client = server->available()) {
+	clients.push_back(client);
+	DIAG(F("New client %s"), client.remoteIP().toString().c_str());
+      }
+    }
+    // loop over all connected clients
+    for (clientId=0; clientId<clients.size(); clientId++){
+      if(clients[clientId].connected()) {
+	int len;
+	if ((len = clients[clientId].available()) > 0) {
+	  // read data from client
+	  byte cmd[len+1];
+	  for(int i=0; i<len; i++) {
+	    cmd[i]=clients[clientId].read();
+	  }
+	  cmd[len]=0;
+	  outboundRing->mark(clientId);
+	  CommandDistributor::parse(clientId,cmd,outboundRing);
+	  outboundRing->commit();
+	}
+      }
+    } // all clients
+
+    // something to write out?
+    clientId=outboundRing->peek();
+    if (clientId >= 0) {
+      if ((unsigned int)clientId > clients.size()) {
+	// something is wrong with the ringbuffer position
+	outboundRing->info();
+      } else {
+	// we have data to send in outboundRing
+	if(clients[clientId].connected()) {
+	  outboundRing->read(); // read over peek()
+	  int count=outboundRing->count();
+	  {
+	    char buffer[count+1];
+	    for(int i=0;i<count;i++) {
+	      int c = outboundRing->read();
+	      if (c >= 0)
+		buffer[i] = (char)c;
+	      else {
+		DIAG(F("Ringread fail at %d"),i);
+		break;
+	      }
+	    }
+	    buffer[count]=0;
+	    clients[clientId].write(buffer,count);
+	  }
+	}
+      }
+    }
+  } //connected
+
+  // when loop() is running on core0 we must
+  // feed the core0 wdt ourselves as yield()
+  // is not necessarily yielding to a low
+  // prio task. On core1 this is not a problem
+  // as there the wdt is disabled by the
+  // arduio IDE startup routines.
+  if (xPortGetCoreID() == 0)
+    feedTheDog0();
+  yield();
+}
+#endif //ESP32

WifiESP32.h

@@ -0,0 +1,39 @@
+/*
+ *  © 2021, Harald Barth.
+ *
+ *  This file is part of CommandStation-EX
+ *
+ *  This is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  It is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#if defined(ARDUINO_ARCH_ESP32)
+#ifndef WifiESP32_h
+#define WifiESP32_h
+
+#include "FSH.h"
+
+class WifiESP
+{
+
+public:
+  static bool setup(const char *wifiESSID,
+		    const char *wifiPassword,
+		    const char *hostname,
+		    const int port,
+		    const byte channel);
+  static void loop();
+private:
+};
+#endif //WifiESP8266_h
+#endif //ESP8266