more random bits there

Function issueReminders was taking around 1700us to complete.  It has been refactored to optimise calculations and reduce the amount of the loco table that needs to be scanned each time.  It now takes typically under 50us to execute.

.gitattributes

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

.github/FUNDING.yml

@@ -0,0 +1,2 @@
+github: DCC-EX
+patreon: dccex

.github/workflows/label-sponsors.yml

@@ -0,0 +1,14 @@
+name: Label sponsors
+on:
+  pull_request:
+    types: [opened]
+  issues:
+    types: [opened]
+jobs:
+  build:
+    name: is-sponsor-label
+    runs-on: ubuntu-latest
+    steps:
+      - uses: JasonEtco/is-sponsor-label-action@v1.2.0
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.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 +1,35 @@
+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@v8 # You can change this to use a specific version
+        with:
+          add: 'GITHUB_SHA.h'
+          message: 'Committing a SHA'
+          commit: --amend
+
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }} # Leave this line unchanged
+          

.gitignore

@@ -6,4 +6,16 @@ Release/*
 .gcc-flags.json
 .pio/
 .vscode/
-config.h
+config.h
+.vscode/*
+# mySetup.h
+mySetup.cpp
+myHal.cpp
+# myAutomation.h
+myFilter.cpp
+# myAutomation.h
+# myLayout.h
+my*.h
+!my*.example.h
+.vscode/extensions.json
+.vscode/extensions.json

.vscode/extensions.json

@@ -3,5 +3,8 @@
     // for the documentation about the extensions.json format
     "recommendations": [
         "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
     ]
 }

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

@@ -1,6 +1,9 @@
 /*
- *  © 2020,Gregor Baues,  Chris Harlow. All rights reserved.
- *  
+ *  © 2022 Harald Barth
+ *  © 2020-2021 Chris Harlow
+ *  © 2020 Gregor Baues
+ *  All rights reserved.
+ *
  *  This file is part of CommandStation-EX
  *
  *  This is free software: you can redistribute it and/or modify
@@ -16,16 +19,171 @@
  *  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 "CommandDistributor.h"
+#include "SerialManager.h"
 #include "WiThrottle.h"
+#include "DIAG.h"
+#include "defines.h"
+#include "DCCWaveform.h"
+#include "DCC.h"
+#include "TrackManager.h"
 
-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
-  }
-  else WiThrottle::getThrottle(clientId)->parse(streamer, buffer);
+#if WIFI_ON || ETHERNET_ON || defined(SERIAL1_COMMANDS) || defined(SERIAL2_COMMANDS) || defined(SERIAL3_COMMANDS)
+// use a buffer to allow broadcast
+StringBuffer * CommandDistributor::broadcastBufferWriter=new StringBuffer();
+template<typename... Targs> void CommandDistributor::broadcastReply(clientType type, Targs... msg){
+  broadcastBufferWriter->flush();
+  StringFormatter::send(broadcastBufferWriter, msg...);
+  broadcastToClients(type);
+}
+#else
+// on a single USB connection config, write direct to Serial and ignore flush/shove
+template<typename... Targs> void CommandDistributor::broadcastReply(clientType type, Targs... msg){
+  (void)type; //shut up compiler warning
+  StringFormatter::send(&Serial, msg...);
+}
+#endif 
+
+#ifdef CD_HANDLE_RING
+  // wifi or ethernet ring streams with multiple client types
+  RingStream *  CommandDistributor::ring=0;
+  CommandDistributor::clientType  CommandDistributor::clients[8]={
+    NONE_TYPE,NONE_TYPE,NONE_TYPE,NONE_TYPE,NONE_TYPE,NONE_TYPE,NONE_TYPE,NONE_TYPE};
+
+// Parse is called by Withrottle or Ethernet interface to determine which
+// protocol the client is using and call the appropriate part of dcc++Ex
+void  CommandDistributor::parse(byte clientId,byte * buffer, RingStream * stream) {
+  if (Diag::WIFI && Diag::CMD)
+    DIAG(F("Parse C=%d T=%d B=%s"),clientId, clients[clientId], buffer);
+  ring=stream;
+
+  // First check if the client is not known
+  // yet and in that case determinine type
+  // NOTE: First character of transmission determines if this
+  // client is using the DCC++ protocol where all commands start
+  // with '<'
+  if (clients[clientId] == NONE_TYPE) {
+    if (buffer[0] == '<')
+      clients[clientId]=COMMAND_TYPE;
+    else
+      clients[clientId]=WITHROTTLE_TYPE;
+  }
+
+  // mark buffer that is sent to parser
+  ring->mark(clientId);
+
+  // When type is known, send the string
+  // to the right parser
+  if (clients[clientId] == COMMAND_TYPE) {
+    DCCEXParser::parse(stream, buffer, ring);
+  } else if (clients[clientId] == WITHROTTLE_TYPE) {
+    WiThrottle::getThrottle(clientId)->parse(ring, buffer);
+  }
+
+  if (ring->peekTargetMark()!=RingStream::NO_CLIENT) {
+    // The commit call will either write the length bytes
+    // OR rollback to the mark because the reply is empty
+    // or the command generated more output than fits in
+    // the buffer
+    if (!ring->commit()) {
+      DIAG(F("OUTBOUND FULL processing cmd:%s"),buffer);
+    }
+  } else {
+    DIAG(F("CD parse: was alredy committed")); //XXX Could have been committed by broadcastClient?!
+  }
+}
+
+void CommandDistributor::forget(byte clientId) {
+  // keep for later if (clients[clientId]==WITHROTTLE_TYPE) WiThrottle::forget(clientId);
+  clients[clientId]=NONE_TYPE;
+}
+#endif 
+
+// This will not be called on a uno 
+void CommandDistributor::broadcastToClients(clientType type) {
+
+  byte rememberClient;
+  (void)rememberClient; // shut up compiler warning
+
+  // Broadcast to Serials
+  if (type==COMMAND_TYPE) SerialManager::broadcast(broadcastBufferWriter->getString());
+
+#ifdef CD_HANDLE_RING
+  // If we are broadcasting from a wifi/eth process we need to complete its output
+  // before merging broadcasts in the ring, then reinstate it in case
+  // the process continues to output to its client.
+  if (ring) {
+    if ((rememberClient = ring->peekTargetMark()) != RingStream::NO_CLIENT) {
+      //DIAG(F("CD precommit client %d"), rememberClient);
+      ring->commit();
+    }
+    // loop through ring clients
+    for (byte clientId=0; clientId<sizeof(clients); clientId++) {
+      if (clients[clientId]==type)  {
+	//DIAG(F("CD mark client %d"), clientId);
+	ring->mark(clientId);
+	ring->print(broadcastBufferWriter->getString());
+	//DIAG(F("CD commit client %d"), clientId);
+	ring->commit();
+      }
+    }
+    // at this point ring is committed (NO_CLIENT) either from
+    // 4 or 13 lines above.
+    if (rememberClient != RingStream::NO_CLIENT) {
+      //DIAG(F("CD postmark client %d"), rememberClient);
+      ring->mark(rememberClient);
+    }
+  }
+#endif
+}
+
+// Public broadcast functions below 
+void  CommandDistributor::broadcastSensor(int16_t id, bool on ) {
+  broadcastReply(COMMAND_TYPE, F("<%c %d>\n"), on?'Q':'q', id);
+}
+
+void  CommandDistributor::broadcastTurnout(int16_t id, bool isClosed ) {
+  // For DCC++ classic compatibility, state reported to JMRI is 1 for thrown and 0 for closed;
+  // The string below contains serial and Withrottle protocols which should
+  // be safe for both types.
+  broadcastReply(COMMAND_TYPE, F("<H %d %d>\n"),id, !isClosed);
+#ifdef CD_HANDLE_RING
+  broadcastReply(WITHROTTLE_TYPE, F("PTA%c%d\n"), isClosed?'2':'4', id);
+#endif
+}
+
+void  CommandDistributor::broadcastLoco(byte slot) {
+  DCC::LOCO * sp=&DCC::speedTable[slot];
+  broadcastReply(COMMAND_TYPE, F("<l %d %d %d %l>\n"), sp->loco,slot,sp->speedCode,sp->functions);
+#ifdef CD_HANDLE_RING
+  WiThrottle::markForBroadcast(sp->loco);
+#endif
+}
+
+void  CommandDistributor::broadcastPower() {
+  bool main=TrackManager::getMainPower()==POWERMODE::ON;
+  bool prog=TrackManager::getProgPower()==POWERMODE::ON;
+  bool join=TrackManager::isJoined();
+  const FSH * reason=F("");
+  char state='1';
+  if (main && prog && join) reason=F(" JOIN");
+  else if (main && prog);
+  else if (main) reason=F(" MAIN");
+  else if (prog) reason=F(" PROG");
+  else state='0';
+  broadcastReply(COMMAND_TYPE, F("<p%c%S>\n"),state,reason);
+#ifdef CD_HANDLE_RING
+  broadcastReply(WITHROTTLE_TYPE, F("PPA%c\n"), main?'1':'0');
+#endif
+  LCD(2,F("Power %S%S"),state=='1'?F("On"):F("Off"),reason);  
+}
+
+void CommandDistributor::broadcastText(const FSH * msg) {
+  broadcastReply(COMMAND_TYPE, F("<I %S>\n"),msg);
+#ifdef CD_HANDLE_RING
+  broadcastReply(WITHROTTLE_TYPE, F("Hm%S\n"), msg);
+#endif
 }

CommandDistributor.h

@@ -1,6 +1,9 @@
 /*
- *  © 2020,Gregor Baues,  Chris Harlow. All rights reserved.
- *  
+ *  © 2022 Harald Barth
+ *  © 2020-2021 Chris Harlow
+ *  © 2020 Gregor Baues
+ *  All rights reserved.
+ *
  *  This file is part of CommandStation-EX
  *
  *  This is free software: you can redistribute it and/or modify
@@ -20,13 +23,32 @@
 #define CommandDistributor_h
 #include "DCCEXParser.h"
 #include "RingStream.h"
+#include "StringBuffer.h"
+#include "defines.h"
+
+#if WIFI_ON | ETHERNET_ON 
+  // Command Distributor must handle a RingStream of clients
+  #define CD_HANDLE_RING
+#endif 
 
 class CommandDistributor {
-
-public :
-  static void parse(byte clientId,byte* buffer, RingStream * streamer);
 private:
-   static DCCEXParser * parser;
+  enum clientType: byte {NONE_TYPE,COMMAND_TYPE,WITHROTTLE_TYPE};
+  static void broadcastToClients(clientType type);
+  static StringBuffer * broadcastBufferWriter;
+  #ifdef CD_HANDLE_RING
+    static RingStream * ring;
+    static clientType clients[8];
+  #endif
+public :
+  static void parse(byte clientId,byte* buffer, RingStream * ring);
+  static void broadcastLoco(byte slot);
+  static void broadcastSensor(int16_t id, bool value);
+  static void broadcastTurnout(int16_t id, bool isClosed);
+  static void broadcastPower();
+  static void broadcastText(const FSH * msg);
+  template<typename... Targs> static void broadcastReply(clientType type, Targs... msg);
+  static void forget(byte clientId);
 };
 
 #endif

CommandStation-EX.ino

@@ -1,21 +1,68 @@
 ////////////////////////////////////////////////////////////////////////////////////
-//  © 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.
 //
-//  THE WIFI FEATURE IS NOT SUPPORTED ON ARDUINO DEVICES WITH ONLY 2KB RAM.
+// 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.
+//
+// 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"
+  #ifndef MOTOR_SHIELD_TYPE
+  #error Your config.h must include a MOTOR_SHIELD_TYPE definition. If you see this warning in spite not having a config.h, you have a buggy preprocessor and must copy config.example.h to config.h
+  #endif
+#else
+  #warning config.h not found. Using defaults from config.example.h
+  #include "config.example.h"
+#endif
+
+/*
+ *  © 2021 Neil McKechnie
+ *  © 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, 
-// This supports JMRI or manual diagnostics and commands
-// to be issued from the USB serial console.
-DCCEXParser serialParser;
+#ifdef CPU_TYPE_ERROR
+#error CANNOT COMPILE - DCC++ EX ONLY WORKS WITH THE ARCHITECTURES LISTED IN defines.h
+#endif
+
+#ifdef WIFI_WARNING
+#warning You have defined that you want WiFi but your hardware has not enough memory to do that, so WiFi DISABLED
+#endif
+#ifdef ETHERNET_WARNING
+#warning You have defined that you want Ethernet but your hardware has not enough memory to do that, so Ethernet DISABLED
+#endif
+#ifdef EXRAIL_WARNING
+#warning You have myAutomation.h but your hardware has not enough memory to do that, so EX-RAIL DISABLED
+#endif
 
 void setup()
 {
@@ -23,33 +70,60 @@ 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));
-   
+  SerialManager::init();
+
+  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")); 
-    }   
-
-//  Start the WiFi interface on a MEGA, Uno cannot currently handle WiFi
+    LCD(1,F("Lic GPLv3"));
+  }
 
+  // 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
+#ifndef ARDUINO_ARCH_ESP32
 #if WIFI_ON
-  WifiInterface::setup(WIFI_SERIAL_LINK_SPEED, F(WIFI_SSID), F(WIFI_PASSWORD), F(WIFI_HOSTNAME), IP_PORT);
+  WifiInterface::setup(WIFI_SERIAL_LINK_SPEED, F(WIFI_SSID), F(WIFI_PASSWORD), F(WIFI_HOSTNAME), IP_PORT, WIFI_CHANNEL);
 #endif // WIFI_ON
+#else
+  // ESP32 needs wifi on always
+  WifiESP::setup(WIFI_SSID, WIFI_PASSWORD, WIFI_HOSTNAME, IP_PORT, WIFI_CHANNEL);
+#endif // ARDUINO_ARCH_ESP32
+
+#if ETHERNET_ON
+  EthernetInterface::setup();
+#endif // ETHERNET_ON
+
+  // Initialise HAL layer before reading EEprom or setting up MotorDrivers 
+  IODevice::begin();
 
   // Responsibility 3: Start the DCC engine.
   // 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
+  TrackManager::Setup(MOTOR_SHIELD_TYPE);
 
-  // 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
+  // Start RMFT aka EX-RAIL (ignored if no automnation)
+  RMFT::begin();
 
-  DCC::begin(MOTOR_SHIELD_TYPE); 
-  LCD(1,F("Ready")); 
+
+  // 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) DCCEXParser::parse(F(cmd))
+    #include "mySetup.h"
+    #undef SETUP
+  #endif
+
+  #if defined(LCN_SERIAL)
+  LCN_SERIAL.begin(115200);
+  LCN::init(LCN_SERIAL);
+  #endif
+  LCD(3, F("Ready"));
+  CommandDistributor::broadcastPower();
 }
 
 void loop()
@@ -61,24 +135,41 @@ void loop()
   DCC::loop();
 
   // Responsibility 2: handle any incoming commands on USB connection
-  serialParser.loop(Serial);
+  SerialManager::loop();
 
-// Responsibility 3: Optionally handle any incoming WiFi traffic
+  // Responsibility 3: Optionally handle any incoming WiFi traffic
+#ifndef ARDUINO_ARCH_ESP32
 #if WIFI_ON
   WifiInterface::loop();
+#endif //WIFI_ON
+#else  //ARDUINO_ARCH_ESP32
+#ifndef WIFI_TASK_ON_CORE0
+  WifiESP::loop();
+#endif
+#endif //ARDUINO_ARCH_ESP32
+#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 (freeNow < ramLowWatermark)
-  {
+  #if defined(LCN_SERIAL)
+  LCN::loop();
+  #endif
+
+  LCDDisplay::loop();  // ignored if LCD not in use
+
+  // Handle/update IO devices.
+  IODevice::loop();
+
+  Sensor::checkAll(); // Update and print changes
+
+  // Report any decrease in memory (will automatically trigger on first call)
+  static int ramLowWatermark = __INT_MAX__; // replaced on first loop
+
+  int freeNow = DCCTimer::getMinimumFreeMemory();
+  if (freeNow < ramLowWatermark) {
     ramLowWatermark = freeNow;
-    LCD(2,F("Free RAM=%5db"), ramLowWatermark);
+    LCD(3,F("Free RAM=%5db"), ramLowWatermark);
   }
-#endif
 }

DCC.h

@@ -1,5 +1,10 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2021 Mike S
+ *  © 2021 Fred Decker
+ *  © 2021 Herb Morton
+ *  © 2020-2021 Harald Barth
+ *  © 2020-2021 Chris Harlow
+ *  All rights reserved.
  *  
  *  This file is part of Asbelos DCC API
  *
@@ -21,82 +26,70 @@
 #include <Arduino.h>
 #include "MotorDriver.h"
 #include "MotorDrivers.h"
+#include "FSH.h"
 
-typedef void (*ACK_CALLBACK)(int result);
+#include "defines.h"
+#ifndef HIGHEST_SHORT_ADDR
+#define HIGHEST_SHORT_ADDR 127
+#else
+#if HIGHEST_SHORT_ADDR > 127
+#error short addr greater than 127 does not make sense
+#endif
+#endif
+#include "DCCACK.h"
+const uint16_t LONG_ADDR_MARKER = 0x4000;
 
-enum ackOp
-{           // Program opcodes for the ack Manager
-  BASELINE, // ensure enough resets sent before starting and obtain baseline current
-  W0,
-  W1,               // issue write bit (0..1) packet
-  WB,               // issue write byte packet
-  VB,               // Issue validate Byte packet
-  V0,               // Issue validate bit=0 packet
-  V1,               // issue validate bit=1 packlet
-  WACK,             // wait for ack (or absence of ack)
-  ITC1,             // If True Callback(1)  (if prevous WACK got an ACK)
-  ITC0,             // If True callback(0);
-  ITCB,             // If True callback(byte)
-  NAKFAIL,          // if false callback(-1)
-  FAIL,             // callback(-1)
-  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
-  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
-};
 
 // Allocations with memory implications..!
 // Base system takes approx 900 bytes + 8 per loco. Turnouts, Sensors etc are dynamically created
-#ifdef ARDUINO_AVR_UNO
-const byte MAX_LOCOS = 20;
-#else
+#if defined(HAS_ENOUGH_MEMORY)
 const byte MAX_LOCOS = 50;
+#else
+const byte MAX_LOCOS = 30;
 #endif
 
 class DCC
 {
 public:
-  static void begin(const __FlashStringHelper *motorShieldName, MotorDriver *mainDriver, MotorDriver *progDriver, byte timerNumber = 1);
+  static void begin(const FSH * motorShieldName);
   static void loop();
 
   // Public DCC API functions
   static void setThrottle(uint16_t cab, uint8_t tSpeed, bool tDirection);
-  static uint8_t getThrottleSpeed(int cab);
+  static int8_t getThrottleSpeed(int cab);
+  static uint8_t getThrottleSpeedByte(int cab);
   static bool getThrottleDirection(int cab);
   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 setAccessory(int aAdd, byte aNum, bool activate);
+  static bool setFn(int cab, int16_t functionNumber, bool on);
+  static void changeFn(int cab, int16_t functionNumber);
+  static int  getFn(int cab, int16_t functionNumber);
+  static uint32_t getFunctionMap(int cab);
+  static void updateGroupflags(byte &flags, int16_t functionNumber);
+  static void setAccessory(int address, byte port, bool gate, byte onoff = 2);
   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();
-
-private:
+  static FSH *getMotorShieldName();
+  static inline void setGlobalSpeedsteps(byte s) {
+    globalSpeedsteps = s;
+  };
+  
   struct LOCO
   {
     int loco;
@@ -104,34 +97,26 @@ private:
     byte groupFlags;
     unsigned long functions;
   };
+ static LOCO speedTable[MAX_LOCOS];
+ static int lookupSpeedTable(int locoId, bool autoCreate=true);
+ static byte cv1(byte opcode, int cv);
+ static byte cv2(int cv);
+ 
+private:
   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 int lastLocoReminder;
+  static int highestUsedReg;
+  static FSH *shieldName;
+  static byte globalSpeedsteps;
 
-  static LOCO speedTable[MAX_LOCOS];
-  static byte cv1(byte opcode, int cv);
-  static byte cv2(int cv);
-  static int lookupSpeedTable(int locoId);
   static void issueReminders();
   static void callback(int value);
 
-  // ACK MANAGER
-  static ackOp const *ackManagerProg;
-  static byte ackManagerByte;
-  static byte ackManagerBitNum;
-  static int ackManagerCv;
-  static byte ackManagerStash;
-  static bool ackReceived;
-  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 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;
@@ -145,23 +130,4 @@ private:
   static const byte BIT_OFF = 0x00;
 };
 
-#ifdef ARDUINO_AVR_MEGA // is using Mega 1280, define as Mega 2560 (pinouts and functionality are identical)
-#define ARDUINO_AVR_MEGA2560
-#endif
-
-#if defined(ARDUINO_AVR_UNO)
-#define ARDUINO_TYPE "UNO"
-#elif defined(ARDUINO_AVR_NANO)
-#define ARDUINO_TYPE "NANO"
-#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"
-#else
-#error CANNOT COMPILE - DCC++ EX ONLY WORKS WITH AN ARDUINO UNO, NANO 328, OR ARDUINO MEGA 1280/2560
-#endif
-
-
 #endif

DCCACK.cpp

@@ -0,0 +1,469 @@
+/*
+ *  © 2021 M Steve Todd
+ *  © 2021 Mike S
+ *  © 2021 Fred Decker
+ *  © 2020-2021 Harald Barth
+ *  © 2020-2022 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 "DCCACK.h"
+#include "DIAG.h"
+#include "DCC.h"
+#include "DCCWaveform.h"
+#include "TrackManager.h"
+
+unsigned int DCCACK::minAckPulseDuration = 2000; // micros
+unsigned int DCCACK::maxAckPulseDuration = 20000; // micros
+  
+MotorDriver *  DCCACK::progDriver=NULL;
+ackOp  const *  DCCACK::ackManagerProg;
+ackOp  const *  DCCACK::ackManagerProgStart;
+byte   DCCACK::ackManagerByte;
+byte   DCCACK::ackManagerByteVerify;
+byte   DCCACK::ackManagerStash;
+int    DCCACK::ackManagerWord;
+byte   DCCACK::ackManagerRetry;
+byte   DCCACK::ackRetry = 2;
+int16_t  DCCACK::ackRetrySum;
+int16_t  DCCACK::ackRetryPSum;
+int    DCCACK::ackManagerCv;
+byte   DCCACK::ackManagerBitNum;
+bool   DCCACK::ackReceived;
+bool   DCCACK::ackManagerRejoin;
+volatile uint8_t DCCACK::numAckGaps=0;
+volatile uint8_t DCCACK::numAckSamples=0;
+uint8_t DCCACK::trailingEdgeCounter=0;
+
+
+ unsigned int DCCACK::ackPulseDuration;  // micros
+ unsigned long DCCACK::ackPulseStart; // micros
+ volatile bool DCCACK::ackDetected;
+ unsigned long DCCACK::ackCheckStart; // millis
+ volatile bool DCCACK::ackPending;
+  bool   DCCACK::autoPowerOff;
+   int  DCCACK::ackThreshold; 
+   int  DCCACK::ackLimitmA = 50;
+     int DCCACK::ackMaxCurrent;
+      unsigned int DCCACK::ackCheckDuration; // millis       
+    
+    
+CALLBACK_STATE DCCACK::callbackState=READY;
+
+ACK_CALLBACK DCCACK::ackManagerCallback;
+
+void  DCCACK::Setup(int cv, byte byteValueOrBitnum, ackOp const program[], ACK_CALLBACK callback) {
+  ackManagerRejoin=TrackManager::isJoined();
+  if (ackManagerRejoin) {
+    // Change from JOIN must zero resets packet.
+    TrackManager::setJoin(false);
+    DCCWaveform::progTrack.clearResets();
+  }
+
+  progDriver=TrackManager::getProgDriver();
+  if (progDriver==NULL) {
+    TrackManager::setJoin(ackManagerRejoin);
+    callback(-3); // we dont have a prog track!
+    return;
+  }
+  if (!progDriver->canMeasureCurrent()) {
+    TrackManager::setJoin(ackManagerRejoin);
+    callback(-2); // our prog track cant measure current
+    return;
+  }
+
+   autoPowerOff=false;
+   if (progDriver->getPower() == POWERMODE::OFF) {
+        autoPowerOff=true;  // power off afterwards
+        if (Diag::ACK) DIAG(F("Auto Prog power on"));
+        progDriver->setPower(POWERMODE::ON);
+	
+    /* TODO !!! in MotorDriver surely!
+    if (MotorDriver::commonFaultPin)
+	  DCCWaveform::mainTrack.setPowerMode(POWERMODE::ON);
+        DCCWaveform::progTrack.clearResets();
+   **/
+      }
+
+
+  ackManagerCv = cv;
+  ackManagerProg = program;
+  ackManagerProgStart = program;
+  ackManagerRetry = ackRetry;
+  ackManagerByte = byteValueOrBitnum;
+  ackManagerByteVerify = byteValueOrBitnum;
+  ackManagerBitNum=byteValueOrBitnum;
+  ackManagerCallback = callback;
+}
+
+void  DCCACK::Setup(int wordval, ackOp const program[], ACK_CALLBACK callback) {
+  ackManagerWord=wordval;
+  Setup(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 DCCACK::checkResets(uint8_t numResets) {
+  return DCCWaveform::progTrack.getResets() < numResets;
+}
+// Operations applicable to PROG track ONLY.
+// (yes I know I could have subclassed the main track but...) 
+
+void DCCACK::setAckBaseline() {
+      int baseline=progDriver->getCurrentRaw();
+      ackThreshold= baseline + progDriver->mA2raw(ackLimitmA);
+      if (Diag::ACK) DIAG(F("ACK baseline=%d/%dmA Threshold=%d/%dmA Duration between %uus and %uus"),
+			  baseline,progDriver->raw2mA(baseline),
+			  ackThreshold,progDriver->raw2mA(ackThreshold),
+                          minAckPulseDuration, maxAckPulseDuration);
+}
+
+void DCCACK::setAckPending() {
+      ackMaxCurrent=0;
+      ackPulseStart=0;
+      ackPulseDuration=0;
+      ackDetected=false;
+      ackCheckStart=millis();
+      numAckSamples=0;
+      numAckGaps=0;
+      ackPending=true;  // interrupt routines will now take note
+}
+
+byte DCCACK::getAck() {
+      if (ackPending) return (2);  // still waiting
+      if (Diag::ACK) DIAG(F("%S after %dmS max=%d/%dmA pulse=%uuS samples=%d gaps=%d"),ackDetected?F("ACK"):F("NO-ACK"), ackCheckDuration,
+			  ackMaxCurrent,progDriver->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 DCCACK::loop() {
+  while (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.)
+    switch (opcode) {
+      case BASELINE:
+          if (progDriver->getPower()==POWERMODE::OVERLOAD) return;
+      	  if (checkResets(autoPowerOff || ackManagerRejoin  ? 20 : 3)) return;
+          setAckBaseline();
+          callbackState=AFTER_READ;
+          break;
+      case W0:    // write 0 bit
+      case W1:    // write 1 bit
+            {
+	      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[] = {DCC::cv1(BIT_MANIPULATE, ackManagerCv), DCC::cv2(ackManagerCv), instruction };
+              DCCWaveform::progTrack.schedulePacket(message, sizeof(message), PROG_REPEATS);
+              setAckPending();
+             callbackState=AFTER_WRITE;
+         }
+            break;
+
+      case WB:   // write byte
+            {
+	      if (checkResets( RESET_MIN)) return;
+              if (Diag::ACK) DIAG(F("WB cv=%d value=%d"),ackManagerCv,ackManagerByte);
+              byte message[] = {DCC::cv1(WRITE_BYTE, ackManagerCv), DCC::cv2(ackManagerCv), ackManagerByte};
+              DCCWaveform::progTrack.schedulePacket(message, sizeof(message), PROG_REPEATS);
+              setAckPending();
+              callbackState=AFTER_WRITE;
+            }
+            break;
+
+      case   VB:     // Issue validate Byte packet
+        {
+	  if (checkResets( RESET_MIN)) return;
+          if (Diag::ACK) DIAG(F("VB cv=%d value=%d"),ackManagerCv,ackManagerByte);
+          byte message[] = { DCC::cv1(VERIFY_BYTE, ackManagerCv), DCC::cv2(ackManagerCv), ackManagerByte};
+          DCCWaveform::progTrack.schedulePacket(message, sizeof(message), PROG_REPEATS);
+          setAckPending();
+        }
+        break;
+
+      case V0:
+      case V1:      // Issue validate bit=0 or bit=1  packet
+        {
+	  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[] = {DCC::cv1(BIT_MANIPULATE, ackManagerCv), DCC::cv2(ackManagerCv), instruction };
+          DCCWaveform::progTrack.schedulePacket(message, sizeof(message), PROG_REPEATS);
+          setAckPending();
+        }
+        break;
+
+      case WACK:   // wait for ack (or absence of ack)
+         {
+          byte ackState=2; // keep polling
+
+          ackState=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) {
+            callback(opcode==ITC0?0:1);
+            return;
+          }
+        break;
+
+      case ITCB:   // If True callback(byte)
+          if (ackReceived) {
+            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) {
+            callback(-1);
+            return;
+          }
+        break;
+
+      case CALLFAIL:  // callback(-1)
+           callback(-1);
+           return;
+
+      case BIV:     // ackManagerByte initial value
+           ackManagerByte = ackManagerByteVerify;
+           break;
+
+      case STARTMERGE:
+           ackManagerBitNum=7;
+           ackManagerByte=0;
+          break;
+
+      case MERGE:  // Merge previous Validate zero wack response with byte value and update bit number (use for reading CV bytes)
+          ackManagerByte <<= 1;
+          // ackReceived means bit is zero.
+          if (!ackReceived) ackManagerByte |= 1;
+          ackManagerBitNum--;
+          break;
+
+      case SETBIT:
+          ackManagerProg++;
+          ackManagerBitNum=GETFLASH(ackManagerProg);
+          break;
+
+     case SETCV:
+          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:
+          ackManagerStash=ackManagerByte;  // stash value from CV17
+          break;
+
+     case COMBINELOCOID:
+          // ackManagerStash is  cv17, ackManagerByte is CV 18
+          callback( LONG_ADDR_MARKER | ( ackManagerByte + ((ackManagerStash - 192) << 8)));
+          return;
+
+     case ITSKIP:
+          if (!ackReceived) break;
+          // SKIP opcodes until SKIPTARGET found
+          while (opcode!=SKIPTARGET) {
+            ackManagerProg++;
+            opcode=GETFLASH(ackManagerProg);
+          }
+          break;
+     case SKIPTARGET:
+          break;
+     default:
+          DIAG(F("!! ackOp %d FAULT!!"),opcode);
+          callback( -1);
+          return;
+
+      }  // end of switch
+    ackManagerProg++;
+  }
+}
+
+void DCCACK::callback(int value) {
+    // 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_READ:
+         if (ackManagerRejoin && autoPowerOff) {
+                progDriver->setPower(POWERMODE::OFF);
+                callbackStart=millis();
+                callbackState=WAITING_30;
+                if (Diag::ACK) DIAG(F("OFF 30mS"));
+        } else {
+               callbackState=READY;
+        }
+        break;
+
+      case AFTER_WRITE:  // first attempt to callback after a write operation
+	    if (!ackManagerRejoin && !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 (autoPowerOff) callbackState=READY;
+            else { // Need to cycle power off and on
+                progDriver->setPower(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
+            progDriver->setPower(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 (autoPowerOff) {
+              if (Diag::ACK) DIAG(F("Auto Prog power off"));
+              progDriver->setPower(POWERMODE::OFF);
+              /* TODO 
+	      if (MotorDriver::commonFaultPin)
+		DCCWaveform::mainTrack.setPowerMode(POWERMODE::OFF);
+        **/
+           }
+          // Restore <1 JOIN> to state before BASELINE
+          if (ackManagerRejoin) {
+              TrackManager::setJoin(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);
+    }
+}
+
+
+void DCCACK::checkAck(byte sentResetsSincePacket) {
+    if (!ackPending) return; 
+    // 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; 
+    }
+      
+    int current=progDriver->getCurrentRaw(true); // true means "from interrupt"
+    numAckSamples++;
+    if (current > ackMaxCurrent) ackMaxCurrent=current;
+    // An ACK is a pulse lasting between minAckPulseDuration and maxAckPulseDuration uSecs (refer @haba)
+        
+    if (current>ackThreshold) {
+       if (trailingEdgeCounter > 0) {
+	 numAckGaps++;
+	 trailingEdgeCounter = 0;
+       }
+       if (ackPulseStart==0) ackPulseStart=micros();    // leading edge of pulse detected
+       return;
+    }
+    
+    // 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
+    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;
+        DCCWaveform::progTrack.clearRepeats();  // shortcut remaining repeat packets 
+        return;  // we have a genuine ACK result
+    }      
+    ackPulseStart=0;  // We have detected a too-short or too-long pulse so ignore and wait for next leading edge 
+}
+

DCCACK.h

@@ -0,0 +1,156 @@
+/*
+ *  © 2021 M Steve Todd
+ *  © 2021 Mike S
+ *  © 2021 Fred Decker
+ *  © 2020-2021 Harald Barth
+ *  © 2020-2022 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 DCCACK_h
+#define DCCACK_h
+
+#include "MotorDriver.h"
+
+typedef void (*ACK_CALLBACK)(int16_t result);
+
+enum ackOp : byte
+{           // Program opcodes for the ack Manager
+  BASELINE, // ensure enough resets sent before starting and obtain baseline current
+  W0,
+  W1,               // issue write bit (0..1) packet
+  WB,               // issue write byte packet
+  VB,               // Issue validate Byte packet
+  V0,               // Issue validate bit=0 packet
+  V1,               // issue validate bit=1 packlet
+  WACK,             // wait for ack (or absence of ack)
+  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)
+  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_READ,   // Start callback sequence after something was read from the decoder  
+  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  
+  }; 
+
+
+
+class DCCACK {
+  public:
+    static byte getAck();               //prog track only 0=NACK, 1=ACK 2=keep waiting
+    static void checkAck(byte sentResetsSincePacket); // Interrupt time ack checker
+    static inline void setAckLimit(int mA) {
+	ackLimitmA = mA;
+    }
+    static inline void setMinAckPulseDuration(unsigned int i) {
+	minAckPulseDuration = i;
+    }
+    static inline void setMaxAckPulseDuration(unsigned int i) {
+	maxAckPulseDuration = i;
+    }
+
+    static void  Setup(int cv, byte byteValueOrBitnum, ackOp const program[], ACK_CALLBACK callback);
+    static void  Setup(int wordval, ackOp const program[], ACK_CALLBACK callback);
+    static void loop();
+    static bool isActive() { return ackManagerProg!=NULL;}
+  static inline int16_t setAckRetry(byte retry) {
+    ackRetry = retry;
+    ackRetryPSum = ackRetrySum;
+    ackRetrySum = 0;  // reset running total
+    return ackRetryPSum;
+  };
+
+
+  private:
+    static const byte SET_SPEED = 0x3f;
+    static const byte WRITE_BYTE = 0x7C;
+    static const byte VERIFY_BYTE = 0x74;
+    static const byte BIT_MANIPULATE = 0x78;
+    static const byte WRITE_BIT = 0xF0;
+    static const byte VERIFY_BIT = 0xE0;
+    static const byte BIT_ON = 0x08;
+    static const byte BIT_OFF = 0x00;
+ 
+    static void setAckBaseline();
+    static void setAckPending();  
+    static void callback(int value);
+    
+    static const int PROG_REPEATS = 8; // repeats of programming commands (some decoders need at least 8 to be reliable)
+    
+    // ACK management (Prog track only)  
+    static void checkAck();
+    static bool checkResets(uint8_t numResets);
+
+    static volatile bool ackPending;
+    static volatile bool ackDetected;
+    static int  ackThreshold; 
+    static int  ackLimitmA;
+    static int ackMaxCurrent;
+    static unsigned long ackCheckStart; // millis
+    static unsigned int ackCheckDuration; // millis       
+    
+    static unsigned int ackPulseDuration;  // micros
+    static unsigned long ackPulseStart; // micros
+
+    static unsigned int minAckPulseDuration ; // micros
+    static unsigned int maxAckPulseDuration ; // micros
+    static MotorDriver* progDriver;
+    static volatile uint8_t numAckGaps;
+    static volatile uint8_t numAckSamples;
+    static uint8_t trailingEdgeCounter;
+    static ackOp  const *  ackManagerProg;
+static ackOp  const *  ackManagerProgStart;
+static byte   ackManagerByte;
+static byte   ackManagerByteVerify;
+static byte   ackManagerStash;
+static int    ackManagerWord;
+static byte   ackManagerRetry;
+static byte   ackRetry;
+static int16_t ackRetrySum;
+static int16_t  ackRetryPSum;
+static int    ackManagerCv;
+static byte   ackManagerBitNum;
+static bool   ackReceived;
+static bool   ackManagerRejoin;
+static bool   autoPowerOff;
+static CALLBACK_STATE callbackState;
+static ACK_CALLBACK ackManagerCallback;
+
+
+};
+#endif

DCCEX.h

@@ -1,3 +1,25 @@
+/*
+ *  © 2021 Fred Decker
+ *  © 2020-2021 Harald Barth
+ *  © 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/>.
+ */
+
 // 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.  
 
@@ -8,11 +30,25 @@
 #include "DCC.h"
 #include "DIAG.h"
 #include "DCCEXParser.h"
+#include "SerialManager.h"
 #include "version.h"
+#ifndef ARDUINO_ARCH_ESP32
 #include "WifiInterface.h"
-#include "EthernetInterface.h"
-#include "LCD_Implementation.h"
-#include "freeMemory.h"
-#include <Arduino.h>
-
+#else
+#include "WifiESP32.h"
+#endif
+#if ETHERNET_ON == true
+#include "EthernetInterface.h"
+#endif
+#include "LCD_Implementation.h"
+#include "LCN.h"
+#include "IODevice.h"
+#include "Turnouts.h"
+#include "Sensors.h"
+#include "Outputs.h"
+#include "CommandDistributor.h"
+#include "TrackManager.h"
+#include "DCCTimer.h"    
+#include "EXRAIL.h"
+    
 #endif

DCCEXParser.h

@@ -1,5 +1,8 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2021 Mike S
+ *  © 2021 Fred Decker
+ *  © 2020-2021 Chris Harlow
+ *  All rights reserved.
  *  
  *  This file is part of Asbelos DCC API
  *
@@ -19,49 +22,57 @@
 #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 (*AT_COMMAND_CALLBACK)(const byte * command);
+typedef void (*FILTER_CALLBACK)(Print * stream, byte & opcode, byte & paramCount, int16_t p[]);
+typedef void (*AT_COMMAND_CALLBACK)(HardwareSerial * stream,const byte * command);
 
 struct DCCEXParser
 {
-   DCCEXParser();
-   void loop(Stream & stream);
-   void parse(Print * stream,  byte * command, bool blocking);
-   void flush();
+   
+   static void parse(Print * stream,  byte * command,  RingStream * ringStream);
+   static void parse(const FSH * cmd);
+   static void parseOne(Print * stream,  byte * command,  RingStream * ringStream);
    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
-     byte  bufferLength=0;
-     bool  inCommandPayload=false;
-     byte  buffer[MAX_BUFFER+2]; 
-    int splitValues( int result[MAX_PARAMS], const byte * command);
+    static const int16_t MAX_BUFFER=50;  // longest command sent in
+    static int16_t splitValues( int16_t result[MAX_COMMAND_PARAMS], const byte * command, bool usehex);
      
-     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[]);
+    static bool parseT(Print * stream, int16_t params, int16_t p[]);
+     static bool parseZ(Print * stream, int16_t params, int16_t p[]);
+     static bool parseS(Print * stream,  int16_t params, int16_t p[]);
+     static bool parsef(Print * stream,  int16_t params, int16_t p[]);
+     static 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];
+    static bool stashCallback(Print * stream, int16_t p[MAX_COMMAND_PARAMS], RingStream * ringStream);
+    static void callback_W(int16_t result);
+    static void callback_W4(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 bool funcmap(int16_t cab, byte value, byte fstart, byte fstop);
+    static void sendFlashList(Print * stream,const int16_t flashList[]);
 
 };
 

DCCRMT.cpp

@@ -0,0 +1,235 @@
+/*
+ *  © 2021-2022, 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/>.
+ */
+
+#if defined(ARDUINO_ARCH_ESP32)
+#include "defines.h"
+#include "DIAG.h"
+#include "DCCRMT.h"
+#include "DCCTimer.h"
+#include "DCCWaveform.h" // for MAX_PACKET_SIZE
+#include "soc/gpio_sig_map.h"
+
+// Number of bits resulting out of X bytes of DCC payload data
+// Each byte has one bit extra and at the end we have one EOF marker
+#define DATA_LEN(X) ((X)*9+1)
+
+#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;
+}
+
+// This is an array that contains the this pointers
+// to all uses channel objects. This is used to determine
+// which of the channels was triggering the ISR as there
+// is only ONE common ISR routine for all channels.
+RMTChannel *channelHandle[8] = { 0 };
+
+void IRAM_ATTR interrupt(rmt_channel_t channel, void *t) {
+  RMTChannel *tt = channelHandle[channel];
+  if (tt) tt->RMTinterrupt();
+  if (channel == 0)
+    DCCTimer::updateMinimumFreeMemoryISR(0);
+}
+
+RMTChannel::RMTChannel(pinpair pins, bool isMain) {
+  byte ch;
+  byte plen;
+  if (isMain) {
+    ch = 0;
+    plen = PREAMBLE_BITS_MAIN;
+  } else {
+    ch = 2;
+    plen = PREAMBLE_BITS_PROG;
+  }
+    
+  // 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));
+  if (isMain) {
+    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);
+  } else {
+    for (byte n=0; n<26; n++)  // all zero
+      setDCCBit0(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+1);  // plus checksum
+  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)pins.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));
+  addPin(pins.invpin, true);
+  /*
+  // test: config another gpio pin
+  gpio_num_t gpioNum = (gpio_num_t)(pin-1);
+  PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[gpioNum], PIN_FUNC_GPIO);
+  gpio_set_direction(gpioNum, GPIO_MODE_OUTPUT);
+  gpio_matrix_out(gpioNum, RMT_SIG_OUT0_IDX, 0, 0);
+  */
+  
+  // 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));
+  channelHandle[channel] = this; // used by interrupt
+  rmt_register_tx_end_callback(interrupt, 0);
+  rmt_set_tx_intr_en(channel, true);
+
+  DIAG(F("Channel %d DCC signal for %s start"), config.channel, isMain ? "MAIN" : "PROG");
+
+  // 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();
+  dataReady = false;
+}
+
+void RMTChannel::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};
+
+int RMTChannel::RMTfillData(const byte buffer[], byte byteCount, byte repeatCount=0) {
+  //int RMTChannel::RMTfillData(dccPacket packet) {
+  // dataReady: Signals to then interrupt routine. It is set when
+  // we have data in the channel buffer which can be copied out
+  // to the HW. dataRepeat on the other hand signals back to
+  // the caller of this function if the data has been sent enough
+  // times (0 to 3 means 1 to 4 times in total).
+  if (dataRepeat > 0) // we have still old work to do
+    return dataRepeat;
+  if (dataReady == true) // the packet is not copied out yet
+    return 1000;
+  if (DATA_LEN(byteCount) > maxDataLen) {  // this would overun our allocated memory for data
+    DIAG(F("Can not convert DCC bytes # %d to DCC bits %d, buffer too small"), byteCount, maxDataLen);
+    return -1;                          // 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+1;         // repeatCount of 0 means send once
+  return 0;
+}
+
+void IRAM_ATTR RMTChannel::RMTinterrupt() {
+  //no rmt_tx_start(channel,true) as we run in loop mode
+  //preamble is always loaded at beginning of buffer
+  packetCounter++;
+  if (!dataReady && dataRepeat == 0) { // we did run empty
+    rmt_fill_tx_items(channel, idle, idleLen, preambleLen-1);
+    return; // nothing to do about that
+  }
+
+  // take care of incoming data
+  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--;
+}
+
+bool RMTChannel::addPin(byte pin, bool inverted) {
+  if (pin == UNUSED_PIN)
+    return true;
+  gpio_num_t gpioNum = (gpio_num_t)(pin);
+  esp_err_t err;
+  PIN_FUNC_SELECT(GPIO_PIN_MUX_REG[gpioNum], PIN_FUNC_GPIO);
+  err = gpio_set_direction(gpioNum, GPIO_MODE_OUTPUT);
+  if (err != ESP_OK) return false;
+  gpio_matrix_out(gpioNum, RMT_SIG_OUT0_IDX+channel, inverted, 0);
+  if (err != ESP_OK) return false;
+  return true;
+}
+bool RMTChannel::addPin(pinpair pins) {
+  return addPin(pins.pin) && addPin(pins.invpin, true);
+}
+#endif //ESP32

DCCRMT.h

@@ -0,0 +1,66 @@
+/*
+ *  © 2021-2022, 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/>.
+ */
+
+#if defined(ARDUINO_ARCH_ESP32)
+#pragma once
+#include <Arduino.h>
+#include "driver/rmt.h"
+#include "soc/rmt_reg.h"
+#include "soc/rmt_struct.h"
+#include "MotorDriver.h" // for class pinpair
+
+// 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 RMTChannel {
+ public:
+  RMTChannel(pinpair pins, bool isMain);
+  bool addPin(byte pin, bool inverted=0);
+  bool addPin(pinpair pins);
+  void IRAM_ATTR RMTinterrupt();
+  void RMTprefill();
+  //int RMTfillData(dccPacket packet);
+  int RMTfillData(const byte buffer[], byte byteCount, byte repeatCount);
+  inline bool busy() {
+    if (dataRepeat > 0) // we have still old work to do
+      return true;
+    return dataReady;
+  };
+  inline uint32_t packetCount() { return packetCounter; };
+  
+ 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;
+  uint32_t packetCounter = 0;
+  // flags 
+  volatile bool dataReady = false;    // do we have real data available or send idle
+  volatile byte dataRepeat = 0;
+};
+#endif //ESP32

DCCTimer.h

@@ -0,0 +1,132 @@
+/*
+ *  © 2022 Paul M. Antoine
+ *  © 2021 Mike S
+ *  © 2021-2022 Harald Barth
+ *  © 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/>.
+ */
+
+/* There are several different implementations of this class which the compiler will select 
+   according to the hardware.
+   */
+
+/* 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.
+ *  
+ */
+
+#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);
+  static void clearPWM();
+// Update low ram level.  Allow for extra bytes to be specified
+// by estimation or inspection, that may be used by other 
+// called subroutines.  Must be called with interrupts disabled.
+// 
+// Although __brkval may go up and down as heap memory is allocated
+// and freed, this function records only the worst case encountered.
+// So even if all of the heap is freed, the reported minimum free 
+// memory will not increase.
+//
+  static void inline updateMinimumFreeMemoryISR(unsigned char extraBytes=0)
+    __attribute__((always_inline)) {
+    int spare = freeMemory()-extraBytes;
+    if (spare < 0) spare = 0;
+    if (spare < minimum_free_memory) minimum_free_memory = spare;
+  };
+
+  static int  getMinimumFreeMemory();
+  static void reset();
+  
+private:
+  static int freeMemory();
+  static volatile int minimum_free_memory;
+  static const int DCC_SIGNAL_TIME=58;  // this is the 58uS DCC 1-bit waveform half-cycle 
+#if defined(ARDUINO_ARCH_STM32)  // TODO: PMA temporary hack - assumes 100Mhz F_CPU as STM32 can change frequency
+  static const long CLOCK_CYCLES=(100000000L / 1000000 * DCC_SIGNAL_TIME) >>1;
+#else
+  static const long CLOCK_CYCLES=(F_CPU / 1000000 * DCC_SIGNAL_TIME) >>1;
+#endif
+
+};
+
+// Class ADCee implements caching of the ADC value for platforms which
+// have a too slow ADC read to wait for. On these platforms the ADC is
+// scanned continiously in the background from an ISR. On such
+// architectures that use the analog read during DCC waveform with
+// specially configured ADC, for example AVR, init must be called
+// PRIOR to the start of the waveform. It returns the current value so
+// that an offset can be initialized.
+class ADCee {
+public:
+  // init does add the pin to the list of scanned pins (if this
+  // platform's implementation scans pins) and returns the first
+  // read value. It is called before the regular scan is started.
+  static int init(uint8_t pin);
+  // read does read the pin value from the scanned cache or directly
+  // if this is a platform that does not scan. fromISR is a hint if
+  // it was called from ISR because for some implementations that
+  // makes a difference.
+  static int read(uint8_t pin, bool fromISR=false);
+  // returns possible max value that the ADC can return
+  static int16_t ADCmax();
+private:
+  // On platforms that scan, it is called from waveform ISR
+  // only on a regular basis.
+  static void scan();
+  // begin is called for any setup that must be done before
+  // scan can be called.
+  static void begin();
+  // bit array of used pins (max 16)
+  static uint16_t usedpins;
+  // cached analog values (malloc:ed to actual number of ADC channels)
+  static int *analogvals;
+  // ids to scan (new way)
+  static byte *idarr;
+  // friend so that we can call scan() and begin()
+  friend class DCCWaveform;
+  };
+#endif

DCCTimerAVR.cpp

@@ -0,0 +1,231 @@
+/*
+ *  © 2021 Mike S
+ *  © 2021-2022 Harald Barth
+ *  © 2021 Fred Decker
+ *  © 2021 Chris Harlow
+ *  © 2021 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/>.
+ */
+
+// ATTENTION: this file only compiles on a UNO or MEGA
+// Please refer to DCCTimer.h for general comments about how this class works
+// This is to avoid repetition and duplication.
+#ifdef ARDUINO_ARCH_AVR
+#include <avr/boot.h> 
+#include <avr/wdt.h>
+#include "DCCTimer.h"
+INTERRUPT_CALLBACK interruptHandler=0;
+
+  // 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();
+    TCCR1A = 0;
+    ICR1 = CLOCK_CYCLES;
+    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       
+ }
+
+void DCCTimer::clearPWM() {
+  TCCR1A= 0;
+}
+
+  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;
+  }
+
+
+volatile int DCCTimer::minimum_free_memory=__INT_MAX__;
+
+// Return low memory value... 
+int DCCTimer::getMinimumFreeMemory() {
+  noInterrupts(); // Disable interrupts to get volatile value 
+  int retval = minimum_free_memory;
+  interrupts();
+  return retval;
+}
+
+extern char *__brkval;
+extern char *__malloc_heap_start;
+
+int DCCTimer::freeMemory() {
+  char top;
+  return __brkval ? &top - __brkval : &top - __malloc_heap_start;
+}
+
+void DCCTimer::reset() {
+  wdt_enable( WDTO_15MS); // set Arduino watchdog timer for 15ms 
+  delay(50);            // wait for the prescaller time to expire
+
+}
+
+#if defined(ARDUINO_AVR_MEGA) || defined(ARDUINO_AVR_MEGA2560)
+#define NUM_ADC_INPUTS 16
+#else
+#define NUM_ADC_INPUTS 8
+#endif
+uint16_t ADCee::usedpins = 0;
+int * ADCee::analogvals = NULL;
+byte *ADCee::idarr = NULL;
+static bool ADCusesHighPort = false;
+
+/*
+ * Register a new pin to be scanned
+ * Returns current reading of pin and
+ * stores that as well
+ */
+int ADCee::init(uint8_t pin) {
+  uint8_t id = pin - A0;
+  byte n;
+  if (id >= NUM_ADC_INPUTS)
+    return -1023;
+  if (id > 7)
+    ADCusesHighPort = true;
+  pinMode(pin, INPUT);
+  int value = analogRead(pin);
+  if (analogvals == NULL) {
+    analogvals = (int *)calloc(NUM_ADC_INPUTS, sizeof(int));
+    for (n=0 ; n < NUM_ADC_INPUTS; n++) // set unreasonable value at startup as marker
+      analogvals[n] = -32768;           // 16 bit int min value
+    idarr = (byte *)calloc(NUM_ADC_INPUTS+1, sizeof(byte));  // +1 for terminator value
+    for (n=0 ; n <= NUM_ADC_INPUTS; n++)
+      idarr[n] = 255;                   // set 255 as end of array marker
+  }
+  analogvals[id] = value; // store before enable by idarr[n]
+  for (n=0 ; n <= NUM_ADC_INPUTS; n++) {
+    if (idarr[n] == 255) {
+      idarr[n] = id;
+      break;
+    }
+  }
+  return value;
+}
+int16_t ADCee::ADCmax() {
+  return 1023;
+}
+/*
+ * Read function ADCee::read(pin) to get value instead of analogRead(pin)
+ */
+int ADCee::read(uint8_t pin, bool fromISR) {
+  (void)fromISR; // AVR does ignore this arg
+  uint8_t id = pin - A0;
+  int a;
+  // we do not need to check (analogvals == NULL)
+  // because usedpins would still be 0 in that case
+  noInterrupts();
+  a = analogvals[id];
+  interrupts();
+  return a;
+}
+/*
+ * Scan function that is called from interrupt
+ */
+#pragma GCC push_options
+#pragma GCC optimize ("-O3")
+void ADCee::scan() {
+  static byte num = 0;       // index into id array
+  static bool waiting = false;
+
+  if (waiting) {
+    // look if we have a result
+    byte low, high;
+    if (bit_is_set(ADCSRA, ADSC))
+      return; // no result, continue to wait
+    // found value
+    low = ADCL; //must read low before high
+    high = ADCH;
+    bitSet(ADCSRA, ADIF);
+    analogvals[idarr[num]] = (high << 8) | low;
+    waiting = false;
+  }
+  if (!waiting) {
+    // cycle around in-use analogue pins
+    num++;
+    if (idarr[num] == 255)
+      num = 0;
+    // start new ADC aquire on id
+#if defined(ADCSRB) && defined(MUX5)
+    if (ADCusesHighPort) {     // if we ever have started to use high pins)
+      if (idarr[num] > 7)              // if we use a high ADC pin
+	bitSet(ADCSRB, MUX5);  // set MUX5 bit
+      else
+	bitClear(ADCSRB, MUX5);
+    }
+#endif
+    ADMUX = (1 << REFS0) | (idarr[num] & 0x07); // select AVCC as reference and set MUX
+    bitSet(ADCSRA, ADSC);               // start conversion
+    waiting = true;
+  }
+}
+#pragma GCC pop_options
+
+void ADCee::begin() {
+  noInterrupts();
+  // ADCSRA = (ADCSRA & 0b11111000) | 0b00000100;   // speed up analogRead sample time
+  // Set up ADC for free running mode
+  ADMUX=(1<<REFS0); //select AVCC as reference. We set MUX later
+  ADCSRA = (1<<ADEN)|(1 << ADPS2); // ADPS2 means divisor 32 and 16Mhz/32=500kHz.
+  //bitSet(ADCSRA, ADSC); //do not start the ADC yet. Done when we have set the MUX
+  interrupts();
+}
+#endif

DCCTimerESP.cpp

@@ -0,0 +1,178 @@
+/*
+ *  © 2020-2022 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/>.
+ */
+
+// ATTENTION: this file only compiles on an ESP8266 and ESP32
+// On ESP32 we do not even use the functions but they are here for completeness sake
+// Please refer to DCCTimer.h for general comments about how this class works
+// This is to avoid repetition and duplication.
+
+#ifdef ARDUINO_ARCH_ESP8266
+
+#include "DCCTimer.h"
+INTERRUPT_CALLBACK interruptHandler=0;
+
+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) {
+}
+void IRAM_ATTR DCCTimer::clearPWM() {
+}
+
+// Fake this as it should not be used
+void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+  mac[0] = 0xFE;
+  mac[1] = 0xBE;
+  mac[2] = 0xEF;
+  mac[3] = 0xC0;
+  mac[4] = 0xFF;
+  mac[5] = 0xEE;
+}
+
+volatile int DCCTimer::minimum_free_memory=__INT_MAX__;
+
+// Return low memory value... 
+int DCCTimer::getMinimumFreeMemory() {
+  noInterrupts(); // Disable interrupts to get volatile value 
+  int retval = minimum_free_memory;
+  interrupts();
+  return retval;
+}
+
+int DCCTimer::freeMemory() {
+  return ESP.getFreeHeap();
+}
+#endif
+
+////////////////////////////////////////////////////////////////////////
+
+#ifdef ARDUINO_ARCH_ESP32
+#include <driver/adc.h>
+#include <soc/sens_reg.h>
+#include <soc/sens_struct.h>
+#undef ADC_INPUT_MAX_VALUE
+#define ADC_INPUT_MAX_VALUE 4095 // 12 bit ADC
+#define pinToADC1Channel(X) (adc1_channel_t)(((X) > 35) ? (X)-36 : (X)-28)
+
+int IRAM_ATTR local_adc1_get_raw(int channel) {
+  uint16_t adc_value;
+  SENS.sar_meas_start1.sar1_en_pad = (1 << channel); // only one channel is selected
+  while (SENS.sar_slave_addr1.meas_status != 0);
+  SENS.sar_meas_start1.meas1_start_sar = 0;
+  SENS.sar_meas_start1.meas1_start_sar = 1;
+  while (SENS.sar_meas_start1.meas1_done_sar == 0);
+  adc_value = SENS.sar_meas_start1.meas1_data_sar;
+  return adc_value;
+}
+
+#include "DCCTimer.h"
+INTERRUPT_CALLBACK interruptHandler=0;
+
+// https://www.visualmicro.com/page/Timer-Interrupts-Explained.aspx
+
+portMUX_TYPE timerMux = portMUX_INITIALIZER_UNLOCKED;
+
+void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
+  // This should not be called on ESP32 so disable it
+  return;
+  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) {
+}
+void IRAM_ATTR DCCTimer::clearPWM() {
+}
+
+// Fake this as it should not be used
+void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+  mac[0] = 0xFE;
+  mac[1] = 0xBE;
+  mac[2] = 0xEF;
+  mac[3] = 0xC0;
+  mac[4] = 0xFF;
+  mac[5] = 0xEE;
+}
+
+volatile int DCCTimer::minimum_free_memory=__INT_MAX__;
+
+// Return low memory value... 
+int DCCTimer::getMinimumFreeMemory() {
+  noInterrupts(); // Disable interrupts to get volatile value 
+  int retval = minimum_free_memory;
+  interrupts();
+  return retval;
+}
+
+int DCCTimer::freeMemory() {
+  return ESP.getFreeHeap();
+}
+
+void DCCTimer::reset() {
+   ESP.restart();
+}
+int ADCee::init(uint8_t pin) {
+  pinMode(pin, ANALOG);
+  adc1_config_width(ADC_WIDTH_BIT_12);
+  adc1_config_channel_atten(pinToADC1Channel(pin),ADC_ATTEN_DB_11);
+  return adc1_get_raw(pinToADC1Channel(pin));
+}
+int16_t ADCee::ADCmax() {
+  return 4095;
+}
+/*
+ * Read function ADCee::read(pin) to get value instead of analogRead(pin)
+ */
+int ADCee::read(uint8_t pin, bool fromISR) {
+  return local_adc1_get_raw(pinToADC1Channel(pin));
+}
+/*
+ * Scan function that is called from interrupt
+ */
+void ADCee::scan() {
+}
+
+void ADCee::begin() {
+}
+
+#endif //ESP32
+

DCCTimerMEGAAVR.cpp

@@ -0,0 +1,155 @@
+/*
+ *  © 2022 Paul M. Antoine
+ *  © 2021 Mike S
+ *  © 2021 Harald Barth
+ *  © 2021 Fred Decker
+ *  © 2021 Chris Harlow
+ *  © 2021 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.
+ *  
+ */
+
+// ATTENTION: this file only compiles on a UnoWifiRev3 or NanoEvery
+// Please refer to DCCTimer.h for general comments about how this class works
+// This is to avoid repetition and duplication.
+#ifdef ARDUINO_ARCH_MEGAAVR
+
+#include "DCCTimer.h"
+
+INTERRUPT_CALLBACK interruptHandler=0;
+extern char *__brkval;
+extern char *__malloc_heap_start;
+
+  
+  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 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; // Clear interrupt request flag
+    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::clearPWM() {
+    // Do nothing unless we implent HA
+}
+
+  void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+    memcpy(mac,(void *) &SIGROW.SERNUM0,6);  // serial number
+    mac[0] &= 0xFE;
+    mac[0] |= 0x02;
+  }
+
+volatile int DCCTimer::minimum_free_memory=__INT_MAX__;
+
+// Return low memory value... 
+int DCCTimer::getMinimumFreeMemory() {
+  noInterrupts(); // Disable interrupts to get volatile value 
+  int retval = minimum_free_memory;
+  interrupts();
+  return retval;
+}
+
+extern char *__brkval;
+extern char *__malloc_heap_start;
+
+int DCCTimer::freeMemory() {
+  char top;
+  return __brkval ? &top - __brkval : &top - __malloc_heap_start;
+}
+
+void DCCTimer::reset() {
+  CPU_CCP=0xD8;
+  WDT.CTRLA=0x4;
+  while(true){}
+}
+
+int16_t ADCee::ADCmax() {
+  return 4095;
+}
+
+int ADCee::init(uint8_t pin) {
+  return analogRead(pin);
+}
+/*
+ * Read function ADCee::read(pin) to get value instead of analogRead(pin)
+ */
+int ADCee::read(uint8_t pin, bool fromISR) {
+  int current;
+  if (!fromISR) noInterrupts();
+  current = analogRead(pin);
+  if (!fromISR) interrupts();
+  return current;
+}
+/*
+ * Scan function that is called from interrupt
+ */
+void ADCee::scan() {
+}
+
+void ADCee::begin() {
+  noInterrupts();
+  interrupts();
+}
+#endif

DCCTimerSAMD.cpp

@@ -0,0 +1,292 @@
+/*
+ *  © 2022 Paul M. Antoine
+ *  © 2021 Mike S
+ *  © 2021-2022 Harald Barth
+ *  © 2021 Fred Decker
+ *  © 2021 Chris Harlow
+ *  © 2021 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/>.
+ */
+
+// ATTENTION: this file only compiles on a SAMD21 based board
+// Please refer to DCCTimer.h for general comments about how this class works
+// This is to avoid repetition and duplication.
+#ifdef ARDUINO_ARCH_SAMD
+
+#include "DCCTimer.h"
+#include <wiring_private.h>
+
+INTERRUPT_CALLBACK interruptHandler=0;
+
+void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
+  interruptHandler=callback;
+  noInterrupts();
+  // Timer setup - setup clock sources first
+  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);
+
+  // Assume we're using TCC0... as we're bit-bashing the DCC waveform output pins anyway
+  // for "normal accuracy" DCC waveform generation. For high accuracy we're going to need
+  // to a good deal more. The TCC waveform output pins are mux'd on the SAMD, and output
+  // pins for each TCC are only available on certain pins
+  TCC0->WAVE.reg = TCC_WAVE_WAVEGEN_NPWM;     // Select NPWM as waveform
+  while (TCC0->SYNCBUSY.bit.WAVE);            // Wait for sync
+
+  // Set the frequency
+  TCC0->CTRLA.reg |= TCC_CTRLA_PRESCALER(TCC_CTRLA_PRESCALER_DIV1_Val);
+  TCC0->PER.reg = CLOCK_CYCLES * 2;
+  while (TCC0->SYNCBUSY.bit.PER);
+
+  // Start the timer
+  TCC0->CTRLA.bit.ENABLE = 1;
+  while (TCC0->SYNCBUSY.bit.ENABLE);
+
+  // Set the interrupt condition, priority and enable it in the NVIC
+  TCC0->INTENSET.reg = TCC_INTENSET_OVF;      // Only interrupt on overflow
+  int USBprio = NVIC_GetPriority((IRQn_Type) USB_IRQn);  // Fetch the USB priority
+  NVIC_SetPriority((IRQn_Type)TCC0_IRQn, USBprio);  // Match the USB priority
+//  NVIC_SetPriority((IRQn_Type)TCC0_IRQn, 0);  // Make this highest priority
+  NVIC_EnableIRQ((IRQn_Type)TCC0_IRQn);       // Enable the interrupt
+  interrupts();
+}
+
+// Timer IRQ handlers replace the dummy handlers (in cortex_handlers)
+// copied from rf24 branch
+void TCC0_Handler() {
+    if(TCC0->INTFLAG.bit.OVF) {
+        TCC0->INTFLAG.bit.OVF = 1; // writing a 1 clears the flag
+        interruptHandler();
+    }
+}
+
+void TCC1_Handler() {
+    if(TCC1->INTFLAG.bit.OVF) {
+        TCC1->INTFLAG.bit.OVF = 1; // writing a 1 clears the flag
+        interruptHandler();
+    }
+}
+
+void TCC2_Handler() {
+    if(TCC2->INTFLAG.bit.OVF) {
+        TCC2->INTFLAG.bit.OVF = 1; // writing a 1 clears the flag
+        interruptHandler();
+    }
+}
+
+
+bool DCCTimer::isPWMPin(byte pin) {
+  //TODO: SAMD whilst this call to digitalPinHasPWM will reveal which pins can do PWM,
+  //      there's no support yet for High Accuracy, so for now return false
+  //  return digitalPinHasPWM(pin);
+  return false;
+}
+
+void DCCTimer::setPWM(byte pin, bool high) {
+    // TODO: High Accuracy mode is not supported as yet, and may never need to be
+    (void) pin;
+    (void) high;
+}
+
+void DCCTimer::clearPWM() {
+  return;
+}
+
+void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+  volatile uint32_t *serno1 = (volatile uint32_t *)0x0080A00C;
+  volatile uint32_t *serno2 = (volatile uint32_t *)0x0080A040;
+//  volatile uint32_t *serno3 = (volatile uint32_t *)0x0080A044;
+//  volatile uint32_t *serno4 = (volatile uint32_t *)0x0080A048;
+
+  volatile uint32_t m1 = *serno1;
+  volatile uint32_t m2 = *serno2;
+  mac[0] = m1 >> 8;
+  mac[1] = m1 >> 0;
+  mac[2] = m2 >> 24;
+  mac[3] = m2 >> 16;
+  mac[4] = m2 >> 8;
+  mac[5] = m2 >> 0;
+}
+
+volatile int DCCTimer::minimum_free_memory=__INT_MAX__;
+
+// Return low memory value... 
+int DCCTimer::getMinimumFreeMemory() {
+  noInterrupts(); // Disable interrupts to get volatile value 
+  int retval = freeMemory();
+  interrupts();
+  return retval;
+}
+
+extern "C" char* sbrk(int incr);
+
+int DCCTimer::freeMemory() {
+  char top;
+  return (int)(&top - reinterpret_cast<char *>(sbrk(0)));
+}
+
+void DCCTimer::reset() {
+   __disable_irq();
+    NVIC_SystemReset();
+    while(true) {};
+}
+
+#define NUM_ADC_INPUTS NUM_ANALOG_INPUTS
+
+uint16_t ADCee::usedpins = 0;
+int * ADCee::analogvals = NULL;
+
+int ADCee::init(uint8_t pin) {
+  uint id = pin - A0;
+  int value = 0;
+
+  if (id > NUM_ADC_INPUTS)
+    return -1023;
+
+  // Dummy read using Arduino library
+  analogReadResolution(12);
+  value = analogRead(pin);
+
+  // Reconfigure ADC
+  ADC->CTRLA.bit.ENABLE = 0;                      // disable ADC
+  while( ADC->STATUS.bit.SYNCBUSY == 1 );         // wait for synchronization
+
+  ADC->CTRLB.reg &= 0b1111100011001111;           // mask PRESCALER and RESSEL bits
+  ADC->CTRLB.reg |= ADC_CTRLB_PRESCALER_DIV64 |   // divide Clock by 16
+                    ADC_CTRLB_RESSEL_12BIT;       // Result 12 bits, 10 bits possible
+  ADC->AVGCTRL.reg = ADC_AVGCTRL_SAMPLENUM_1 |    // take 1 sample at a time
+                     ADC_AVGCTRL_ADJRES(0x00ul);  // adjusting result by 0
+  ADC->SAMPCTRL.reg = 0x00ul;                     // sampling Time Length = 0
+  ADC->CTRLA.bit.ENABLE = 1;                      // enable ADC
+  while( ADC->STATUS.bit.SYNCBUSY == 1 );         // wait for synchronization
+
+  // Permanently configure SAMD IO MUX for that pin
+  pinPeripheral(pin, PIO_ANALOG);
+  ADC->INPUTCTRL.bit.MUXPOS = g_APinDescription[pin].ulADCChannelNumber; // Selection for the positive ADC input
+
+  // Start conversion
+  ADC->SWTRIG.bit.START = 1;
+
+  // Wait for the conversion to be ready
+  while (ADC->INTFLAG.bit.RESRDY == 0);   // Waiting for conversion to complete
+
+  // Read the value
+  value = ADC->RESULT.reg;
+
+  if (analogvals == NULL)
+    analogvals = (int *)calloc(NUM_ADC_INPUTS+1, sizeof(int));
+  analogvals[id] = value;
+  usedpins |= (1<<id);
+
+  return value;
+}
+int16_t ADCee::ADCmax() {
+  return 4095;
+}
+/*
+ * Read function ADCee::read(pin) to get value instead of analogRead(pin)
+ */
+int ADCee::read(uint8_t pin, bool fromISR) {
+  uint8_t id = pin - A0;
+  if ((usedpins & (1<<id) ) == 0)
+    return -1023;
+  // we do not need to check (analogvals == NULL)
+  // because usedpins would still be 0 in that case
+  return analogvals[id];
+}
+/*
+ * Scan function that is called from interrupt
+ */
+#pragma GCC push_options
+#pragma GCC optimize ("-O3")
+void ADCee::scan() {
+  static uint id = 0;        // id and mask are the same thing but it is faster to 
+  static uint16_t mask = 1;  // increment and shift instead to calculate mask from id
+  static bool waiting = false;
+
+  if (waiting) {
+    // look if we have a result
+    if (ADC->INTFLAG.bit.RESRDY == 0)
+      return; // no result, continue to wait
+    // found value
+    analogvals[id] = ADC->RESULT.reg;
+    // advance at least one track
+    // for scope debug TrackManager::track[1]->setBrake(0);
+    waiting = false;
+    id++;
+    mask = mask << 1;
+    if (id == NUM_ADC_INPUTS+1) {
+      id = 0;
+      mask = 1;
+    }
+  }
+  if (!waiting) {
+    if (usedpins == 0) // otherwise we would loop forever
+      return;
+    // look for a valid track to sample or until we are around
+    while (true) {
+      if (mask  & usedpins) {
+    	  // start new ADC aquire on id
+        ADC->INPUTCTRL.bit.MUXPOS = g_APinDescription[id + A0].ulADCChannelNumber; // Selection for the positive ADC input
+          // Start conversion
+        ADC->SWTRIG.bit.START = 1;
+	      // for scope debug TrackManager::track[1]->setBrake(1);
+	      waiting = true;
+	      return;
+      }
+      id++;
+      mask = mask << 1;
+      if (id == NUM_ADC_INPUTS+1) {
+	      id = 0;
+	      mask = 1;
+      }
+    }
+  }
+}
+#pragma GCC pop_options
+
+void ADCee::begin() {
+  noInterrupts();
+  // Set up ADC to do faster reads... default for Arduino Zero platform configs is 436uS,
+  // and we need sub-58uS. This code sets it to a read speed of around 5-6uS, and enables
+  // 12-bit mode
+  // Reconfigure ADC
+  ADC->CTRLA.bit.ENABLE = 0;                      // disable ADC
+  while( ADC->STATUS.bit.SYNCBUSY == 1 );         // wait for synchronization
+
+  ADC->CTRLB.reg &= 0b1111100011001111;           // mask PRESCALER and RESSEL bits
+  ADC->CTRLB.reg |= ADC_CTRLB_PRESCALER_DIV64 |   // divide Clock by 16
+                    ADC_CTRLB_RESSEL_12BIT;       // Result 12 bits, 10 bits possible
+  ADC->AVGCTRL.reg = ADC_AVGCTRL_SAMPLENUM_1 |    // take 1 sample at a time
+                     ADC_AVGCTRL_ADJRES(0x00ul);  // adjusting result by 0
+  ADC->SAMPCTRL.reg = 0x00ul;                     // sampling Time Length = 0
+  ADC->CTRLA.bit.ENABLE = 1;                      // enable ADC
+  while( ADC->STATUS.bit.SYNCBUSY == 1 );         // wait for synchronization
+  interrupts();
+}
+#endif

DCCTimerSTM32.cpp

@@ -0,0 +1,162 @@
+/*
+ *  © 2022 Paul M. Antoine
+ *  © 2021 Mike S
+ *  © 2021 Harald Barth
+ *  © 2021 Fred Decker
+ *  © 2021 Chris Harlow
+ *  © 2021 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/>.
+ */
+
+// ATTENTION: this file only compiles on a STM32 based boards
+// Please refer to DCCTimer.h for general comments about how this class works
+// This is to avoid repetition and duplication.
+#ifdef ARDUINO_ARCH_STM32
+
+#include "FSH.h" //PMA temp debug
+#include "DIAG.h" //PMA temp debug
+#include "DCCTimer.h"
+
+#define STM32F411RE   // PMA - ideally this ought to be derived from within the STM32 support somehow
+
+#if defined(STM32F411RE)
+// STM32F411RE doesn't have Serial1 defined by default
+HardwareSerial Serial1(PB7, PA15);  // Rx=PB7, Tx=PA15 -- CN7 pins 17 and 21 - F411RE
+// Serial2 is defined to use USART2 by default, but is in fact used as the diag console
+// via the debugger on the Nucleo-64 STM32F411RE. It is therefore unavailable
+// for other DCC-EX uses like WiFi, DFPlayer, etc.
+// Let's define Serial6 as an additional serial port (the only other option for the F411RE)
+HardwareSerial Serial6(PA12, PA11);  // Rx=PA12, Tx=PA11 -- CN10 pins 12 and 14 - F411RE
+#elif defined(STM32F446ZE)
+// STM32F446ZE doesn't have Serial1 defined by default
+HardwareSerial Serial1(PG9, PG14);  // Rx=PG9, Tx=PG14 -- D0, D1 - F446ZE
+#else
+#warning Serial1 not defined
+#endif
+
+INTERRUPT_CALLBACK interruptHandler=0;
+// Let's use STM32's timer #11 until disabused of this notion
+// Timer #11 is used for "servo" library, but as DCC-EX is not using
+// this libary, we should be free and clear.
+HardwareTimer timer(TIM11);
+
+// Timer IRQ handler
+void Timer11_Handler() {
+  interruptHandler();
+}
+
+void DCCTimer::begin(INTERRUPT_CALLBACK callback) {
+  interruptHandler=callback;
+  noInterrupts();
+
+  // adc_set_sample_rate(ADC_SAMPLETIME_480CYCLES);
+  timer.pause();
+  timer.setPrescaleFactor(1);
+//  timer.setOverflow(CLOCK_CYCLES * 2);
+  timer.setOverflow(DCC_SIGNAL_TIME, MICROSEC_FORMAT);
+  timer.attachInterrupt(Timer11_Handler);
+  timer.refresh();
+  timer.resume();
+
+  interrupts();
+}
+
+bool DCCTimer::isPWMPin(byte pin) {
+  //TODO: SAMD whilst this call to digitalPinHasPWM will reveal which pins can do PWM,
+  //      there's no support yet for High Accuracy, so for now return false
+  //  return digitalPinHasPWM(pin);
+  return false;
+}
+
+void DCCTimer::setPWM(byte pin, bool high) {
+    // TODO: High Accuracy mode is not supported as yet, and may never need to be
+    (void) pin;
+    (void) high;
+}
+
+void DCCTimer::clearPWM() {
+  return;
+}
+
+void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+  volatile uint32_t *serno1 = (volatile uint32_t *)0x0080A00C;
+  volatile uint32_t *serno2 = (volatile uint32_t *)0x0080A040;
+//  volatile uint32_t *serno3 = (volatile uint32_t *)0x0080A044;
+//  volatile uint32_t *serno4 = (volatile uint32_t *)0x0080A048;
+
+  volatile uint32_t m1 = *serno1;
+  volatile uint32_t m2 = *serno2;
+  mac[0] = m1 >> 8;
+  mac[1] = m1 >> 0;
+  mac[2] = m2 >> 24;
+  mac[3] = m2 >> 16;
+  mac[4] = m2 >> 8;
+  mac[5] = m2 >> 0;
+}
+
+volatile int DCCTimer::minimum_free_memory=__INT_MAX__;
+
+// Return low memory value... 
+int DCCTimer::getMinimumFreeMemory() {
+  noInterrupts(); // Disable interrupts to get volatile value 
+  int retval = freeMemory();
+  interrupts();
+  return retval;
+}
+
+extern "C" char* sbrk(int incr);
+
+int DCCTimer::freeMemory() {
+  char top;
+  return (int)(&top - reinterpret_cast<char *>(sbrk(0)));
+}
+
+void DCCTimer::reset() {
+   __disable_irq();
+    NVIC_SystemReset();
+    while(true) {};
+}
+
+int16_t ADCee::ADCmax() {
+  return 4095;
+}
+
+int ADCee::init(uint8_t pin) {
+  return analogRead(pin);
+}
+/*
+ * Read function ADCee::read(pin) to get value instead of analogRead(pin)
+ */
+int ADCee::read(uint8_t pin, bool fromISR) {
+  int current;
+  if (!fromISR) noInterrupts();
+  current = analogRead(pin);
+  if (!fromISR) interrupts();
+  return current;
+}
+/*
+ * Scan function that is called from interrupt
+ */
+void ADCee::scan() {
+}
+
+void ADCee::begin() {
+  noInterrupts();
+  interrupts();
+}
+#endif

DCCTimerTEENSY.cpp

@@ -0,0 +1,171 @@
+/*
+ *  © 2022 Paul M Antoine
+ *  © 2021 Mike S
+ *  © 2021 Harald Barth
+ *  © 2021 Fred Decker
+ *  © 2021 Chris Harlow
+ *  © 2021 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/>.
+ */
+
+// ATTENTION: this file only compiles on a TEENSY
+// Please refer to DCCTimer.h for general comments about how this class works
+// This is to avoid repetition and duplication.
+#ifdef TEENSYDUINO
+
+#include "DCCTimer.h"
+
+INTERRUPT_CALLBACK interruptHandler=0;
+
+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::clearPWM() {
+    // Do nothing unless we implent HA
+}
+
+#if defined(__IMXRT1062__)  //Teensy 4.0 and Teensy 4.1
+void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+    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
+
+// http://forum.pjrc.com/threads/91-teensy-3-MAC-address
+void teensyRead(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.
+}
+
+void   DCCTimer::getSimulatedMacAddress(byte mac[6]) {
+    teensyRead(0xe,mac,0);
+    teensyRead(0xf,mac,3);
+  }
+#endif 
+
+volatile int DCCTimer::minimum_free_memory=__INT_MAX__;
+
+// Return low memory value... 
+int DCCTimer::getMinimumFreeMemory() {
+  noInterrupts(); // Disable interrupts to get volatile value 
+  int retval = freeMemory();
+  interrupts();
+  return retval;
+}
+
+extern "C" char* sbrk(int incr);
+
+#if !defined(__IMXRT1062__)
+int DCCTimer::freeMemory() {
+  char top;
+  return &top - reinterpret_cast<char*>(sbrk(0));
+}
+
+#else
+#if defined(ARDUINO_TEENSY40)
+  static const unsigned DTCM_START = 0x20000000UL;
+  static const unsigned OCRAM_START = 0x20200000UL;
+  static const unsigned OCRAM_SIZE = 512;
+  static const unsigned FLASH_SIZE = 1984;
+#elif defined(ARDUINO_TEENSY41)
+  static const unsigned DTCM_START = 0x20000000UL;
+  static const unsigned OCRAM_START = 0x20200000UL;
+  static const unsigned OCRAM_SIZE = 512;
+  static const unsigned FLASH_SIZE = 7936;
+#if TEENSYDUINO>151
+  extern "C" uint8_t external_psram_size;
+#endif
+#endif
+
+int DCCTimer::freeMemory() {
+  extern unsigned long _ebss;
+  extern unsigned long _sdata;
+  extern unsigned long _estack;
+  const unsigned DTCM_START = 0x20000000UL;
+  unsigned dtcm = (unsigned)&_estack - DTCM_START;
+  unsigned stackinuse = (unsigned) &_estack -  (unsigned) __builtin_frame_address(0);
+  unsigned varsinuse = (unsigned)&_ebss - (unsigned)&_sdata;
+  unsigned freemem = dtcm - (stackinuse + varsinuse);
+  return freemem;
+}
+
+#endif
+void DCCTimer::reset() {
+  // found at https://forum.pjrc.com/threads/59935-Reboot-Teensy-programmatically
+  SCB_AIRCR = 0x05FA0004;
+}
+
+int16_t ADCee::ADCmax() {
+  return 4095;
+}
+
+int ADCee::init(uint8_t pin) {
+  return analogRead(pin);
+}
+/*
+ * Read function ADCee::read(pin) to get value instead of analogRead(pin)
+ */
+int ADCee::read(uint8_t pin, bool fromISR) {
+  int current;
+  if (!fromISR) noInterrupts();
+  current = analogRead(pin);
+  if (!fromISR) interrupts();
+  return current;
+}
+/*
+ * Scan function that is called from interrupt
+ */
+void ADCee::scan() {
+}
+
+void ADCee::begin() {
+  noInterrupts();
+  interrupts();
+}
+#endif

DCCWaveform.cpp

@@ -1,8 +1,12 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
- *  © 2020, Harald Barth.
+ *  © 2021 Neil McKechnie
+ *  © 2021 Mike S
+ *  © 2021 Fred Decker
+ *  © 2020-2022 Harald Barth
+ *  © 2020-2021 Chris Harlow
+ *  All rights reserved.
  *  
- *  This file is part of Asbelos DCC API
+ *  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
@@ -17,69 +21,81 @@
  *  You should have received a copy of the GNU General Public License
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
+#ifndef ARDUINO_ARCH_ESP32
+  // This code is replaced entirely on an ESP32
 #include <Arduino.h>
 
 #include "DCCWaveform.h"
+#include "TrackManager.h"
+#include "DCCTimer.h"
+#include "DCCACK.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;
+
 
 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) {
-  mainTrack.motorDriver=mainDriver;
-  progTrack.motorDriver=progDriver;
+// This bitmask has 9 entries as each byte is trasmitted as a zero + 8 bits.
+const byte bitMask[] = {0x00, 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01};
 
-  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;
-  }
-  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")); 
+const byte idlePacket[] = {0xFF, 0x00, 0xFF};
+const byte resetPacket[] = {0x00, 0x00, 0x00};
+
+
+// For each state of the wave  nextState=stateTransform[currentState] 
+const WAVE_STATE 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};
+
+// For each state of the wave, signal pin is HIGH or LOW   
+const bool 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};
+
+void DCCWaveform::begin() {
+  ADCee::begin();
+  DCCTimer::begin(DCCWaveform::interruptHandler);     
 }
 
 void DCCWaveform::loop() {
-  mainTrack.checkPowerOverload();
-  progTrack.checkPowerOverload();
+ // empty placemarker in case ESP32 needs something here 
 }
 
-
-// static //
+#pragma GCC push_options
+#pragma GCC optimize ("-O3")
 void DCCWaveform::interruptHandler() {
   // call the timer edge sensitive actions for progtrack and maintrack
-  bool mainCall2 = mainTrack.interrupt1();
-  bool progCall2 = progTrack.interrupt1();
+  // member functions would be cleaner but have more overhead
+  byte sigMain=signalTransform[mainTrack.state];
+  byte sigProg=TrackManager::progTrackSyncMain? sigMain : signalTransform[progTrack.state];
+  
+  // Set the signal state for both tracks
+  TrackManager::setDCCSignal(sigMain);
+  TrackManager::setPROGSignal(sigProg);
+
+  // Refresh the values in the ADCee object buffering the values of the ADC HW
+  ADCee::scan();
+
+  // 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();
+  else DCCACK::checkAck(progTrack.getResets());
 
-  // 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();
 }
-
+#pragma GCC pop_options
 
 // An instance of this class handles the DCC transmissions for one track. (main or prog)
 // Interrupts are marshalled via the statics.
@@ -87,148 +103,40 @@ void DCCWaveform::interruptHandler() {
 // When the current buffer is exhausted, either the pending buffer (if there is one waiting) or an idle buffer.
 
 
-// This bitmask has 9 entries as each byte is trasmitted as a zero + 8 bits.
-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;
   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;
-  sampleDelay = 0;
-  lastSampleTaken = millis();
-  ackPending=false;
-}
-
-POWERMODE DCCWaveform::getPowerMode() {
-  return powerMode;
-}
-
-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);
-}
-
-
-void DCCWaveform::checkPowerOverload() {
-  
-  static int progTripValue = motorDriver->mA2raw(TRIP_CURRENT_PROG); // need only calculate once, hence static
-
-  if (millis() - lastSampleTaken  < sampleDelay) return;
-  lastSampleTaken = millis();
-  int tripValue= motorDriver->getRawCurrentTripValue();
-  if (!isMainTrack && !ackPending && !progTrackSyncMain && !progTrackBoosted)
-    tripValue=progTripValue;
-  
-  switch (powerMode) {
-    case POWERMODE::OFF:
-      sampleDelay = POWER_SAMPLE_OFF_WAIT;
-      break;
-    case POWERMODE::ON:
-      // Check current
-      lastCurrent = motorDriver->getCurrentRaw();
-      if (lastCurrent <= tripValue) {
-        sampleDelay = POWER_SAMPLE_ON_WAIT;
-	if(power_good_counter<100)
-	  power_good_counter++;
-	else
-	  if (power_sample_overload_wait>POWER_SAMPLE_OVERLOAD_WAIT) power_sample_overload_wait=POWER_SAMPLE_OVERLOAD_WAIT;
-      } else {
-        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;
-	if (power_sample_overload_wait >= 10000)
-	    power_sample_overload_wait = 10000;
-	else
-	    power_sample_overload_wait *= 2;
-      }
-      break;
-    case POWERMODE::OVERLOAD:
-      // Try setting it back on after the OVERLOAD_WAIT
-      setPowerMode(POWERMODE::ON);
-      sampleDelay = POWER_SAMPLE_ON_WAIT;
-      break;
-    default:
-      sampleDelay = 999; // cant get here..meaningless statement to avoid compiler warning.
-  }
 }
 
 
 
-
-
-// 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);
-}
-      
+#pragma GCC push_options
+#pragma GCC optimize ("-O3")
 void DCCWaveform::interrupt2() {
-  // set currentBit to be the next bit to be sent.
+  // 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.
+    DCCTimer::updateMinimumFreeMemoryISR(22); 
     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
@@ -248,106 +156,126 @@ void DCCWaveform::interrupt2() {
       }
       else if (packetPending) {
         // Copy pending packet to transmit packet
-        for (int b = 0; b < pendingLength; b++) transmitPacket[b] = pendingPacket[b];
+        // 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;
+        clearResets();
       }
       else {
         // Fortunately reset and idle packets are the same length
         memcpy( transmitPacket, isMainTrack ? idlePacket : resetPacket, sizeof(idlePacket));
         transmitLength = sizeof(idlePacket);
         transmitRepeats = 0;
-        if (sentResetsSincePacket<250) sentResetsSincePacket++;
+        if (getResets() < 250) sentResetsSincePacket++; // only place to increment (private!)
       }
     }
   }  
 }
-
-
+#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);
 
   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;
-  sentResetsSincePacket=0;
+  clearResets();
 }
-
-int DCCWaveform::getLastCurrent() {
-   return lastCurrent;
+bool DCCWaveform::getPacketPending() {
+  return packetPending;
 }
+#endif
 
-// Operations applicable to PROG track ONLY.
-// (yes I know I could have subclassed the main track but...) 
+#ifdef ARDUINO_ARCH_ESP32
+#include "DCCWaveform.h"
+#include "DCCACK.h"
 
-void DCCWaveform::setAckBaseline() {
-      if (isMainTrack) return;
-      int baseline = motorDriver->getCurrentRaw();
-      ackThreshold= baseline + motorDriver->mA2raw(ackLimitmA);
-      if (Diag::ACK) DIAG(F("\nACK baseline=%d/%dmA threshold=%d/%dmA"),
-			  baseline,motorDriver->raw2mA(baseline),
-			  ackThreshold,motorDriver->raw2mA(ackThreshold));
+DCCWaveform  DCCWaveform::mainTrack(PREAMBLE_BITS_MAIN, true);
+DCCWaveform  DCCWaveform::progTrack(PREAMBLE_BITS_PROG, false);
+RMTChannel *DCCWaveform::rmtMainChannel = NULL;
+RMTChannel *DCCWaveform::rmtProgChannel = NULL;
+
+DCCWaveform::DCCWaveform(byte preambleBits, bool isMain) {
+  isMainTrack = isMain;
+  requiredPreambles = preambleBits;
 }
-
-void DCCWaveform::setAckPending() {
-      if (isMainTrack) return; 
-      ackMaxCurrent=0;
-      ackPulseStart=0;
-      ackPulseDuration=0;
-      ackDetected=false;
-      ackCheckStart=millis();
-      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 (ackDetected) return (1); // Yes we had an ack
-      return(0);  // pending set off but not detected means no ACK.   
-}
-
-void 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; 
+void DCCWaveform::begin() {
+  for(const auto& md: TrackManager::getMainDrivers()) {
+    pinpair p = md->getSignalPin();
+    if(rmtMainChannel) {
+      //DIAG(F("added pins %d %d to MAIN channel"), p.pin, p.invpin);
+      rmtMainChannel->addPin(p); // add pin to existing main channel
+    } else {
+      //DIAG(F("new MAIN channel with pins %d %d"), p.pin, p.invpin);
+      rmtMainChannel = new RMTChannel(p, true); /* create new main channel */
     }
-      
-    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)
-        
-    if (lastCurrent>ackThreshold) {
-       if (ackPulseStart==0) ackPulseStart=micros();    // leading edge of pulse detected
-       return;
+  }
+  MotorDriver *md = TrackManager::getProgDriver();
+  if (md) {
+    pinpair p = md->getSignalPin();
+    if (rmtProgChannel) {
+      //DIAG(F("added pins %d %d to PROG channel"), p.pin, p.invpin);
+      rmtProgChannel->addPin(p); // add pin to existing prog channel
+    } else {
+      //DIAG(F("new PROGchannel with pins %d %d"), p.pin, p.invpin);
+      rmtProgChannel = new RMTChannel(p, false);
     }
-    
-    // not in pulse
-    if (ackPulseStart==0) return; // keep waiting for leading edge 
-    
-    // detected trailing edge of pulse
-    ackPulseDuration=micros()-ackPulseStart;
-               
-    if (ackPulseDuration>=MIN_ACK_PULSE_DURATION && ackPulseDuration<=MAX_ACK_PULSE_DURATION) {
-        ackCheckDuration=millis()-ackCheckStart;
-        ackDetected=true;
-        ackPending=false;
-        transmitRepeats=0;  // shortcut remaining repeat packets 
-        return;  // we have a genuine ACK result
-    }      
-    ackPulseStart=0;  // We have detected a too-short or too-long pulse so ignore and wait for next leading edge 
+  }
 }
+
+void DCCWaveform::schedulePacket(const byte buffer[], byte byteCount, byte repeats) {
+  if (byteCount > MAX_PACKET_SIZE) return; // allow for chksum
+  
+  byte checksum = 0;
+  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;
+  // The resets will be zero not only now but as well repeats packets into the future
+  clearResets(repeats+1);
+  {
+    int ret;
+    do {
+      if(isMainTrack) {
+	if (rmtMainChannel != NULL)
+	  ret = rmtMainChannel->RMTfillData(pendingPacket, pendingLength, pendingRepeats);
+      } else {
+	if (rmtProgChannel != NULL)
+	  ret = rmtProgChannel->RMTfillData(pendingPacket, pendingLength, pendingRepeats);
+      }
+    } while(ret > 0);
+  }
+}
+
+bool DCCWaveform::getPacketPending() {
+  if(isMainTrack) {
+    if (rmtMainChannel == NULL)
+      return true;
+    return rmtMainChannel->busy();
+  } else {
+    if (rmtProgChannel == NULL)
+      return true;
+    return rmtProgChannel->busy();
+  }
+}
+void IRAM_ATTR DCCWaveform::loop() {
+  DCCACK::checkAck(progTrack.getResets());
+}
+#endif

DCCWaveform.h

@@ -1,8 +1,12 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
- *  © 2020, Harald Barth.
+ *  © 2021 M Steve Todd
+ *  © 2021 Mike S
+ *  © 2021 Fred Decker
+ *  © 2020-2021 Harald Barth
+ *  © 2020-2021 Chris Harlow
+ *  All rights reserved.
  *  
- *  This file is part of Asbelos DCC API
+ *  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
@@ -19,115 +23,87 @@
  */
 #ifndef DCCWaveform_h
 #define DCCWaveform_h
+
 #include "MotorDriver.h"
-#include "ArduinoTimers.h"
+#ifdef ARDUINO_ARCH_ESP32
+#include "DCCRMT.h"
+#include "TrackManager.h"
+#endif
+
 
-// 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 };
-
-const byte idlePacket[] = {0xFF, 0x00, 0xFF};
-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 begin();
     static void loop();
     static DCCWaveform  mainTrack;
     static DCCWaveform  progTrack;
-
-    void beginTrack();
-    void setPowerMode(POWERMODE);
-    POWERMODE getPowerMode();
-    void checkPowerOverload();
-    int  getLastCurrent();
+    inline void clearRepeats() { transmitRepeats=0; }
+#ifndef ARDUINO_ARCH_ESP32
+    inline void clearResets() { sentResetsSincePacket=0; }
+    inline byte getResets() { return sentResetsSincePacket; }
+#else
+  // extrafudge is added when we know that the resets will first come extrafudge  packets in the future
+    inline void clearResets(byte extrafudge=0) {
+      if ((isMainTrack ? rmtMainChannel : rmtProgChannel) == NULL) return;
+      resetPacketBase = isMainTrack ? rmtMainChannel->packetCount() : rmtProgChannel->packetCount();
+      resetPacketBase += extrafudge;
+    };
+    inline byte getResets() {
+      if ((isMainTrack ? rmtMainChannel : rmtProgChannel) == NULL) return 0;
+      uint32_t packetcount = isMainTrack ?
+	rmtMainChannel->packetCount() : rmtProgChannel->packetCount();
+      uint32_t count = packetcount - resetPacketBase; // Beware of unsigned interger arithmetic.
+      if (count > UINT32_MAX/2)                       // we are in the extrafudge area
+	return 0;
+      if (count > 255)                                // cap to 255
+	return 255;
+      return count;                                   // all special cases handled above
+    };
+#endif
     void schedulePacket(const byte buffer[], byte byteCount, byte repeats);
+    bool getPacketPending();
+    
+  private:
+#ifndef ARDUINO_ARCH_ESP32
     volatile bool packetPending;
     volatile byte sentResetsSincePacket;
-    volatile bool autoPowerOff=false;
-    void setAckBaseline();  //prog track only
-    void setAckPending();  //prog track only
-    byte getAck();               //prog track only 0=NACK, 1=ACK 2=keep waiting
-    static bool progTrackSyncMain;  // true when prog track is a siding switched to main
-    static bool progTrackBoosted;   // true when prog track is not current limited
-    inline void doAutoPowerOff() {
-	if (autoPowerOff) {
-	    setPowerMode(POWERMODE::OFF);
-	    autoPowerOff=false;
-	}
-    };
-    inline void setAckLimit(int mA) {
-	ackLimitmA = mA;
-    }
-     
-  private:
-    static VirtualTimer * interruptTimer;      
+#else
+    volatile uint32_t resetPacketBase;
+#endif
     static void interruptHandler();
-    bool interrupt1();
     void interrupt2();
-    void checkAck();
-    void setSignal(bool high);
     
     bool isMainTrack;
-    MotorDriver*  motorDriver;
     // 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;
-
-    
-    // current sampling
-    POWERMODE powerMode;
-    unsigned long lastSampleTaken;
-    unsigned int sampleDelay;
-    // Trip current for programming track, 250mA. Change only if you really
-    // need to be non-NMRA-compliant because of decoders that are not either.
-    static const int TRIP_CURRENT_PROG=250;
-    unsigned long power_sample_overload_wait = POWER_SAMPLE_OVERLOAD_WAIT;
-    unsigned int power_good_counter = 0;
-
-    // ACK management (Prog track only)  
-    volatile bool ackPending;
-    volatile bool ackDetected;
-    int  ackThreshold; 
-    int  ackLimitmA = 60;
-    int ackMaxCurrent;
-    unsigned long ackCheckStart; // millis
-    unsigned int ackCheckDuration; // millis       
-    
-    unsigned int ackPulseDuration;  // micros
-    unsigned long ackPulseStart; // micros
-           
+#ifdef ARDUINO_ARCH_ESP32
+  static RMTChannel *rmtMainChannel;
+  static RMTChannel *rmtProgChannel;
+#endif
 };
 #endif

DIAG.h

@@ -1,7 +1,9 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2021 Fred Decker
+ *  © 2020 Chris Harlow
+ *  All rights reserved.
  *  
- *  This file is part of Asbelos DCC API
+ *  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
@@ -18,6 +20,7 @@
  */
 #ifndef DIAG_h
 #define DIAG_h
+
 #include "StringFormatter.h"
 #define DIAG  StringFormatter::diag
 #define LCD   StringFormatter::lcd

DisplayInterface.cpp

@@ -1,7 +1,9 @@
 /*
- *  © 2020, Harald Barth
- *  
- *  This file is part of DCC-EX
+ *  © 2021 Neil McKechnie
+ *  © 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
@@ -17,7 +19,6 @@
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  */
 
-#ifndef freeMemory_h
-#define freeMemory_h
-int freeMemory();
-#endif
+#include "DisplayInterface.h"
+
+DisplayInterface *DisplayInterface::lcdDisplay = 0;

DisplayInterface.h

@@ -0,0 +1,37 @@
+/*
+ *  © 2021 Neil McKechnie
+ *  © 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 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

@@ -1,86 +1,112 @@
-#include "EEStore.h"
-#include "Turnouts.h"
-#include "Sensors.h"
-#include "Outputs.h"
-#include "DIAG.h"
+/*
+ *  © 2021 Neil McKechnie
+ *  © 2021 Fred Decker
+ *  © 2020-2022 Harald Barth
+ *  © 2020-2021 Chris Harlow
+ *  © 2013-2016 Gregg E. Berman
+ *  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/>.
+ */
 
-#if defined(ARDUINO_ARCH_SAMD)
+#include "defines.h"
+#ifndef DISABLE_EEPROM
+#include "EEStore.h"
+
+#include "DIAG.h"
+#include "Outputs.h"
+#include "Sensors.h"
+#include "Turnouts.h"
+
+#if defined(ARDUINO_ARCH_SAMC)
 ExternalEEPROM EEPROM;
 #endif
 
-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)
+void EEStore::init() {
+#if defined(ARDUINO_ARCH_SAMC)
+  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)+0);  
+    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,isascii(b) ? b : ' ');
-    }
+  byte b = 0;
+  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;
+#endif

EEStore.h

@@ -1,22 +1,45 @@
+/*
+ *  © 2021 Neil McKechnie
+ *  © 2021 Fred Decker
+ *  © 2020-2021 Harald Barth
+ *  © 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 DISABLE_EEPROM
 #ifndef EEStore_h
 #define EEStore_h
 
 #include <Arduino.h>
 
-#if defined(ARDUINO_ARCH_SAMD)
+#if defined(ARDUINO_ARCH_SAMC)
 #include <SparkFun_External_EEPROM.h>
 extern ExternalEEPROM EEPROM;
 #else
 #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{
@@ -33,3 +56,4 @@ struct EEStore{
 };
 
 #endif
+#endif // DISABLE_EEPROM

ESP32-fixes.cpp

@@ -0,0 +1,61 @@
+/*
+ *  © 2022 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/>.
+ */
+#ifdef ARDUINO_ARCH_ESP32
+#include <Arduino.h>
+#include "ESP32-fixes.h"
+
+#include "esp32-hal.h"
+#include "soc/soc_caps.h"
+
+
+#ifdef SOC_LEDC_SUPPORT_HS_MODE
+#define LEDC_CHANNELS           (SOC_LEDC_CHANNEL_NUM<<1)
+#else
+#define LEDC_CHANNELS           (SOC_LEDC_CHANNEL_NUM)
+#endif
+
+static int8_t pin_to_channel[SOC_GPIO_PIN_COUNT] = { 0 };
+static int cnt_channel = LEDC_CHANNELS;
+
+void DCCEXanalogWriteFrequency(uint8_t pin, uint32_t frequency) {
+  if (pin < SOC_GPIO_PIN_COUNT) {
+    if (pin_to_channel[pin] != 0) {
+      ledcSetup(pin_to_channel[pin], frequency, 8);
+    }
+  }
+}
+
+void DCCEXanalogWrite(uint8_t pin, int value) {
+  if (pin < SOC_GPIO_PIN_COUNT) {
+    if (pin_to_channel[pin] == 0) {
+      if (!cnt_channel) {
+          log_e("No more PWM channels available! All %u already used", LEDC_CHANNELS);
+          return;
+      }
+      pin_to_channel[pin] = --cnt_channel;
+      ledcAttachPin(pin, cnt_channel);
+      ledcSetup(cnt_channel, 1000, 8);
+    } else {
+      ledcAttachPin(pin, pin_to_channel[pin]);
+    }
+    ledcWrite(pin_to_channel[pin], value);
+  }
+}
+#endif

ESP32-fixes.h

@@ -1,5 +1,6 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2022 Harald Barth
+ *  All rights reserved.
  *  
  *  This file is part of CommandStation-EX
  *
@@ -16,12 +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/>.
  */
+#ifdef ARDUINO_ARCH_ESP32
+#pragma once
+#include <Arduino.h>
+void DCCEXanalogWriteFrequency(uint8_t pin, uint32_t frequency);
+void DCCEXanalogWrite(uint8_t pin, int value);
+#endif
 
-// 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(){}
-  

EXRAIL.h

@@ -0,0 +1,23 @@
+#ifndef EXRAIL_H
+#define EXRAIL_H
+
+#if defined(EXRAIL_ACTIVE)
+ #include "EXRAIL2.h"
+
+  class RMFT {
+    public:
+      static void inline begin() {RMFT2::begin();}
+      static void inline loop() {RMFT2::loop();}
+  };
+
+  #include "EXRAILMacros.h"
+  
+#else 
+  // Dummy RMFT 
+  class RMFT {
+    public:
+      static void inline begin() {}
+      static void inline loop() {}
+  };
+#endif
+#endif

EXRAIL2.h

@@ -0,0 +1,186 @@
+/*
+ *  © 2021 Neil McKechnie
+ *  © 2020-2022 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 EXRAIL2_H
+#define EXRAIL2_H
+#include "FSH.h"
+#include "IODevice.h"
+#include "Turnouts.h"
+   
+// The following are the operation codes (or instructions) for a kind of virtual machine.
+// Each instruction is normally 3 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_AUTOSTART,
+             OPCODE_ATGTE,OPCODE_ATLT,
+             OPCODE_ATTIMEOUT1,OPCODE_ATTIMEOUT2,
+             OPCODE_LATCH,OPCODE_UNLATCH,OPCODE_SET,OPCODE_RESET,
+             OPCODE_ENDIF,OPCODE_ELSE,
+             OPCODE_DELAY,OPCODE_DELAYMINS,OPCODE_DELAYMS,OPCODE_RANDWAIT,
+             OPCODE_FON,OPCODE_FOFF,OPCODE_XFON,OPCODE_XFOFF,
+             OPCODE_RED,OPCODE_GREEN,OPCODE_AMBER,OPCODE_DRIVE,
+             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_FORGET,
+             OPCODE_PAUSE, OPCODE_RESUME,OPCODE_POWEROFF,OPCODE_POWERON,
+             OPCODE_ONCLOSE, OPCODE_ONTHROW, OPCODE_SERVOTURNOUT, OPCODE_PINTURNOUT,
+             OPCODE_PRINT,OPCODE_DCCACTIVATE,
+             OPCODE_ONACTIVATE,OPCODE_ONDEACTIVATE,
+             OPCODE_ROSTER,OPCODE_KILLALL,
+             OPCODE_ROUTE,OPCODE_AUTOMATION,OPCODE_SEQUENCE,
+             OPCODE_ENDTASK,OPCODE_ENDEXRAIL,
+             OPCODE_SET_TRACK,
+             OPCODE_ONRED,OPCODE_ONAMBER,OPCODE_ONGREEN,
+
+             // OPcodes below this point are skip-nesting IF operations
+             // placed here so that they may be skipped as a group
+             // see skipIfBlock()
+            IF_TYPE_OPCODES, // do not move this... 
+             OPCODE_IFRED,OPCODE_IFAMBER,OPCODE_IFGREEN,
+             OPCODE_IFGTE,OPCODE_IFLT,
+             OPCODE_IFTIMEOUT,
+             OPCODE_IF,OPCODE_IFNOT,
+             OPCODE_IFRANDOM,OPCODE_IFRESERVE,
+             OPCODE_IFCLOSED,OPCODE_IFTHROWN
+             };
+
+
+ 
+  // Flag bits for status of hardware and TPL
+  static const byte SECTION_FLAG = 0x80;
+  static const byte LATCH_FLAG   = 0x40;
+  static const byte TASK_FLAG    = 0x20;
+  static const byte SPARE_FLAG   = 0x10;
+  static const byte SIGNAL_MASK  = 0x0C;
+  static const byte SIGNAL_RED   = 0x08;
+  static const byte SIGNAL_AMBER = 0x0C;
+  static const byte SIGNAL_GREEN = 0x04;
+
+  static const byte  MAX_STACK_DEPTH=4;
+ 
+   static const short MAX_FLAGS=256;
+  #define FLAGOVERFLOW(x) x>=MAX_FLAGS
+
+class LookList {
+  public: 
+    LookList(int16_t size);
+    void add(int16_t lookup, int16_t result);
+    int16_t find(int16_t value);
+  private:
+     int16_t m_size;
+     int16_t m_loaded;
+     int16_t * m_lookupArray;
+     int16_t * m_resultArray;     
+};
+
+ 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 createNewTask(int route, uint16_t cab);
+    static void turnoutEvent(int16_t id, bool closed);  
+    static void activateEvent(int16_t addr, bool active);
+    static const int16_t SERVO_SIGNAL_FLAG=0x4000;
+    static const int16_t ACTIVE_HIGH_SIGNAL_FLAG=0x2000;
+    static const int16_t DCC_SIGNAL_FLAG=0x1000;
+    static const int16_t SIGNAL_ID_MASK=0x0FFF;
+ 
+ // Throttle Info Access functions built by exrail macros 
+  static const byte rosterNameCount;
+  static const int16_t FLASH routeIdList[];
+  static const int16_t FLASH automationIdList[];
+  static const int16_t FLASH rosterIdList[];
+  static const FSH *  getRouteDescription(int16_t id);
+  static char   getRouteType(int16_t id);
+  static const FSH *  getTurnoutDescription(int16_t id);
+  static const FSH *  getRosterName(int16_t id);
+  static const FSH *  getRosterFunctions(int16_t id);
+    
+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 bool setFlag(VPIN id,byte onMask, byte OffMask=0);
+    static bool getFlag(VPIN id,byte mask); 
+    static int16_t progtrackLocoId;
+    static void doSignal(int16_t id,char rag); 
+    static bool isSignal(int16_t id,char rag); 
+    static int16_t getSignalSlot(int16_t id);
+    static void setTurnoutHiddenState(Turnout * t);
+    static LookList* LookListLoader(OPCODE op1,
+                      OPCODE op2=OPCODE_ENDEXRAIL,OPCODE op3=OPCODE_ENDEXRAIL);
+    static void handleEvent(const FSH* reason,LookList* handlers, int16_t id);
+    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 const  FLASH  int16_t SignalDefinitions[];
+   static byte flags[MAX_FLAGS];
+   static LookList * sequenceLookup;
+   static LookList * onThrowLookup;
+   static LookList * onCloseLookup;
+   static LookList * onActivateLookup;
+   static LookList * onDeactivateLookup;
+   static LookList * onRedLookup;
+   static LookList * onAmberLookup;
+   static LookList * onGreenLookup;
+  
+    
+  // 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  delayTime;
+    union {
+      unsigned long waitAfter; // Used by OPCODE_AFTER
+      unsigned long timeoutStart; // Used by OPCODE_ATTIMEOUT
+    };
+    bool timeoutFlag;
+    byte  taskId;
+    
+    uint16_t loco;
+    bool forward;
+    bool invert;
+    byte speedo;
+    int onEventStartPosition;
+    byte stackDepth;
+    int callStack[MAX_STACK_DEPTH];
+};
+#endif

EXRAIL2MacroReset.h

@@ -0,0 +1,244 @@
+/*
+ *  © 2021-2022 Chris Harlow
+ *  © 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/>.
+ */
+
+// This file cleans and resets the RMFT2 Macros.
+// It is used between passes to reduce complexity in RMFT2Macros.h
+// DO NOT add an include guard to this file.
+
+// Undefine all RMFT macros
+#undef ACTIVATE
+#undef ACTIVATEL
+#undef AFTER
+#undef ALIAS
+#undef AMBER
+#undef AT
+#undef ATGTE
+#undef ATLT
+#undef ATTIMEOUT
+#undef AUTOMATION 
+#undef AUTOSTART
+#undef BROADCAST
+#undef CALL 
+#undef CLOSE 
+#undef DCC_SIGNAL
+#undef DEACTIVATE
+#undef DEACTIVATEL
+#undef DELAY
+#undef DELAYMINS
+#undef DELAYRANDOM 
+#undef DONE
+#undef DRIVE
+#undef ELSE
+#undef ENDEXRAIL 
+#undef ENDIF  
+#undef ENDTASK
+#undef ESTOP 
+#undef EXRAIL  
+#undef FADE
+#undef FOFF
+#undef FOLLOW 
+#undef FON 
+#undef FORGET
+#undef FREE 
+#undef FWD 
+#undef GREEN
+#undef HAL
+#undef IF 
+#undef IFAMBER
+#undef IFCLOSED
+#undef IFGREEN
+#undef IFGTE
+#undef IFLT
+#undef IFNOT
+#undef IFRANDOM 
+#undef IFRED
+#undef IFRESERVE
+#undef IFTHROWN
+#undef IFTIMEOUT
+#undef INVERT_DIRECTION 
+#undef JOIN 
+#undef KILLALL
+#undef LATCH 
+#undef LCD 
+#undef LCN 
+#undef MOVETT
+#undef ONACTIVATE
+#undef ONACTIVATEL
+#undef ONAMBER
+#undef ONDEACTIVATE
+#undef ONDEACTIVATEL 
+#undef ONCLOSE
+#undef ONGREEN
+#undef ONRED
+#undef ONTHROW 
+#undef PARSE
+#undef PAUSE
+#undef PIN_TURNOUT 
+#undef PRINT
+#undef POM
+#undef POWEROFF
+#undef POWERON
+#undef READ_LOCO 
+#undef RED 
+#undef RESERVE 
+#undef RESET 
+#undef RESUME 
+#undef RETURN 
+#undef REV
+#undef ROSTER 
+#undef ROUTE
+#undef SENDLOCO 
+#undef SEQUENCE 
+#undef SERIAL 
+#undef SERIAL1 
+#undef SERIAL2 
+#undef SERIAL3 
+#undef SERVO 
+#undef SERVO2 
+#undef SERVO_TURNOUT 
+#undef SERVO_SIGNAL
+#undef SET
+#undef SET_TRACK
+#undef SETLOCO 
+#undef SIGNAL 
+#undef SIGNALH 
+#undef SPEED 
+#undef START 
+#undef STOP 
+#undef THROW  
+#undef TURNOUT 
+#undef UNJOIN
+#undef UNLATCH 
+#undef VIRTUAL_SIGNAL
+#undef VIRTUAL_TURNOUT
+#undef WAITFOR
+#undef XFOFF
+#undef XFON
+
+#ifndef RMFT2_UNDEF_ONLY
+#define ACTIVATE(addr,subaddr)
+#define ACTIVATEL(addr)
+#define AFTER(sensor_id)
+#define ALIAS(name,value...)
+#define AMBER(signal_id)
+#define AT(sensor_id)
+#define ATGTE(sensor_id,value) 
+#define ATLT(sensor_id,value) 
+#define ATTIMEOUT(sensor_id,timeout_ms)
+#define AUTOMATION(id,description) 
+#define AUTOSTART
+#define BROADCAST(msg)
+#define CALL(route) 
+#define CLOSE(id) 
+#define DCC_SIGNAL(id,add,subaddr)
+#define DEACTIVATE(addr,subaddr)
+#define DEACTIVATEL(addr)
+#define DELAY(mindelay)
+#define DELAYMINS(mindelay)
+#define DELAYRANDOM(mindelay,maxdelay) 
+#define DONE
+#define DRIVE(analogpin)
+#define ELSE
+#define ENDEXRAIL 
+#define ENDIF  
+#define ENDTASK
+#define ESTOP 
+#define EXRAIL  
+#define FADE(pin,value,ms)
+#define FOFF(func)
+#define FOLLOW(route) 
+#define FON(func)
+#define FORGET
+#define FREE(blockid) 
+#define FWD(speed) 
+#define GREEN(signal_id)
+#define HAL(haltype,params...)
+#define IF(sensor_id) 
+#define IFAMBER(signal_id)
+#define IFCLOSED(turnout_id) 
+#define IFGREEN(signal_id)
+#define IFGTE(sensor_id,value) 
+#define IFLT(sensor_id,value) 
+#define IFNOT(sensor_id)
+#define IFRANDOM(percent)
+#define IFRED(signal_id)
+#define IFTHROWN(turnout_id) 
+#define IFRESERVE(block)
+#define IFTIMEOUT
+#define INVERT_DIRECTION 
+#define JOIN 
+#define KILLALL
+#define LATCH(sensor_id) 
+#define LCD(row,msg) 
+#define LCN(msg) 
+#define MOVETT(id,steps,activity)
+#define ONACTIVATE(addr,subaddr)
+#define ONACTIVATEL(linear)
+#define ONAMBER(signal_id) 
+#define ONDEACTIVATE(addr,subaddr)
+#define ONDEACTIVATEL(linear) 
+#define ONCLOSE(turnout_id)
+#define ONGREEN(signal_id) 
+#define ONRED(signal_id) 
+#define ONTHROW(turnout_id) 
+#define PAUSE
+#define PIN_TURNOUT(id,pin,description...) 
+#define PRINT(msg) 
+#define PARSE(msg)
+#define POM(cv,value)
+#define POWEROFF
+#define POWERON
+#define READ_LOCO 
+#define RED(signal_id) 
+#define RESERVE(blockid) 
+#define RESET(pin) 
+#define RESUME 
+#define RETURN 
+#define REV(speed) 
+#define ROUTE(id,description)
+#define ROSTER(cab,name,funcmap...)
+#define SENDLOCO(cab,route) 
+#define SEQUENCE(id) 
+#define SERIAL(msg) 
+#define SERIAL1(msg) 
+#define SERIAL2(msg) 
+#define SERIAL3(msg) 
+#define SERVO(id,position,profile) 
+#define SERVO2(id,position,duration) 
+#define SERVO_SIGNAL(vpin,redpos,amberpos,greenpos)
+#define SERVO_TURNOUT(id,pin,activeAngle,inactiveAngle,profile,description...) 
+#define SET(pin) 
+#define SET_TRACK(track,mode)
+#define SETLOCO(loco) 
+#define SIGNAL(redpin,amberpin,greenpin) 
+#define SIGNALH(redpin,amberpin,greenpin) 
+#define SPEED(speed) 
+#define START(route) 
+#define STOP 
+#define THROW(id)  
+#define TURNOUT(id,addr,subaddr,description...) 
+#define UNJOIN 
+#define UNLATCH(sensor_id) 
+#define VIRTUAL_SIGNAL(id) 
+#define VIRTUAL_TURNOUT(id,description...) 
+#define WAITFOR(pin)
+#define XFOFF(cab,func)
+#define XFON(cab,func)
+#endif

EXRAILMacros.h

@@ -0,0 +1,335 @@
+/*
+ *  © 2021 Neil McKechnie
+ *  © 2020-2022 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 EXRAILMacros_H
+#define EXRAILMacros_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 including 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
+
+
+// helper macro for turnout descriptions, creates NULL for missing description
+#define O_DESC(id, desc) case id: return ("" desc)[0]?F("" desc):NULL;
+// helper macro for turnout description as HIDDEN 
+#define HIDDEN "\x01"
+
+// Pass 1 Implements aliases 
+#include "EXRAIL2MacroReset.h"
+#undef ALIAS
+#define ALIAS(name,value...) const int name= 1##value##0 ==10 ? -__COUNTER__  : value##0/10; 
+#include "myAutomation.h"
+
+// Pass 1h Implements HAL macro by creating exrailHalSetup function 
+#include "EXRAIL2MacroReset.h"
+#undef HAL
+#define HAL(haltype,params...)  haltype::create(params);
+void exrailHalSetup() {
+   #include "myAutomation.h"
+}
+
+// Pass 2 create throttle route list 
+#include "EXRAIL2MacroReset.h"
+#undef ROUTE
+#define ROUTE(id, description) id,
+const int16_t FLASH RMFT2::routeIdList[]= {
+    #include "myAutomation.h"
+    0}; 
+// Pass 2a create throttle automation list 
+#include "EXRAIL2MacroReset.h"
+#undef AUTOMATION
+#define AUTOMATION(id, description) id,
+const int16_t FLASH RMFT2::automationIdList[]= {
+    #include "myAutomation.h"
+    0}; 
+
+// Pass 3 Create route descriptions:
+#undef ROUTE
+#define ROUTE(id, description) case id: return F(description);
+#undef AUTOMATION
+#define AUTOMATION(id, description) case id: return F(description);
+const FSH * RMFT2::getRouteDescription(int16_t id) {
+   switch(id) {
+    #include "myAutomation.h"
+    default: break;
+   }
+   return F("");
+}
+
+// Pass 4... Create Text sending functions
+#include "EXRAIL2MacroReset.h"
+const int StringMacroTracker1=__COUNTER__;
+#undef BROADCAST
+#define BROADCAST(msg) case (__COUNTER__ - StringMacroTracker1) : CommandDistributor::broadcastText(F(msg));break;
+#undef PARSE
+#define PARSE(msg) case (__COUNTER__ - StringMacroTracker1) : DCCEXParser::parse(F(msg));break;
+#undef PRINT
+#define PRINT(msg)    case (__COUNTER__ - StringMacroTracker1) : printMessage2(F(msg));break;
+#undef LCN
+#define LCN(msg)      case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&LCN_SERIAL,F(msg));break;
+#undef SERIAL
+#define SERIAL(msg)   case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&Serial,F(msg));break;
+#undef SERIAL1
+#define SERIAL1(msg)  case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&Serial1,F(msg));break;
+#undef SERIAL2
+#define SERIAL2(msg)  case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&Serial2,F(msg));break;
+#undef SERIAL3
+#define SERIAL3(msg)  case (__COUNTER__ - StringMacroTracker1) : StringFormatter::send(&Serial3,F(msg));break;
+#undef LCD
+#define LCD(id,msg)   case (__COUNTER__ - StringMacroTracker1) : StringFormatter::lcd(id,F(msg));break;
+
+void  RMFT2::printMessage(uint16_t id) { 
+  switch(id) {
+    #include "myAutomation.h"
+    default: break ; 
+  }
+}
+
+
+// Pass 5: Turnout descriptions (optional)
+#include "EXRAIL2MacroReset.h"
+#undef TURNOUT
+#define TURNOUT(id,addr,subaddr,description...) O_DESC(id,description)
+#undef PIN_TURNOUT
+#define PIN_TURNOUT(id,pin,description...) O_DESC(id,description)
+#undef SERVO_TURNOUT
+#define SERVO_TURNOUT(id,pin,activeAngle,inactiveAngle,profile,description...) O_DESC(id,description)
+#undef VIRTUAL_TURNOUT
+#define VIRTUAL_TURNOUT(id,description...) O_DESC(id,description)
+
+const FSH * RMFT2::getTurnoutDescription(int16_t turnoutid) {
+     switch (turnoutid) {
+        #include "myAutomation.h"
+     default:break;
+     }
+     return NULL;
+}
+
+// Pass 6: Roster IDs (count)
+#include "EXRAIL2MacroReset.h"
+#undef ROSTER
+#define ROSTER(cabid,name,funcmap...) +1
+const byte RMFT2::rosterNameCount=0
+   #include "myAutomation.h"
+   ;
+   
+// Pass 6: Roster IDs 
+#include "EXRAIL2MacroReset.h"
+#undef ROSTER
+#define ROSTER(cabid,name,funcmap...) cabid,
+const int16_t FLASH  RMFT2::rosterIdList[]={
+   #include "myAutomation.h"
+   0};
+
+// Pass 7: Roster names getter
+#include "EXRAIL2MacroReset.h"
+#undef ROSTER
+#define ROSTER(cabid,name,funcmap...) case cabid: return F(name);
+const FSH * RMFT2::getRosterName(int16_t id) {
+   switch(id) {
+      #include "myAutomation.h"
+   default: break;
+   }
+   return F("");   
+} 
+
+// Pass to get roster functions 
+#undef ROSTER
+#define ROSTER(cabid,name,funcmap...) case cabid: return F("" funcmap);
+const FSH * RMFT2::getRosterFunctions(int16_t id) {
+   switch(id) {
+      #include "myAutomation.h"
+   default: break; 
+   }   
+   return F("");
+} 
+
+// Pass 8 Signal definitions
+#include "EXRAIL2MacroReset.h"
+#undef SIGNAL
+#define SIGNAL(redpin,amberpin,greenpin) redpin,redpin,amberpin,greenpin, 
+#undef SIGNALH
+#define SIGNALH(redpin,amberpin,greenpin) redpin | RMFT2::ACTIVE_HIGH_SIGNAL_FLAG,redpin,amberpin,greenpin, 
+#undef SERVO_SIGNAL
+#define SERVO_SIGNAL(vpin,redval,amberval,greenval) vpin | RMFT2::SERVO_SIGNAL_FLAG,redval,amberval,greenval, 
+#undef DCC_SIGNAL
+#define DCC_SIGNAL(id,addr,subaddr) id | RMFT2::DCC_SIGNAL_FLAG,addr,subaddr,0,
+#undef VIRTUAL_SIGNAL
+#define VIRTUAL_SIGNAL(id) id,0,0,0,
+
+const  FLASH  int16_t RMFT2::SignalDefinitions[] = {
+    #include "myAutomation.h"
+    0,0,0,0 };
+
+// Last Pass : create main routes table
+// Only undef the macros, not dummy them.  
+#define  RMFT2_UNDEF_ONLY
+#include "EXRAIL2MacroReset.h"
+// Define internal helper macros.
+// Everything we generate here has to be compile-time evaluated to 
+// a constant.  
+#define V(val) (byte)(((int16_t)(val))&0x00FF),(byte)(((int16_t)(val)>>8)&0x00FF)
+// Define macros for route code creation 
+
+#define ACTIVATE(addr,subaddr) OPCODE_DCCACTIVATE,V(addr<<3 | subaddr<<1 | 1),
+#define ACTIVATEL(addr) OPCODE_DCCACTIVATE,V((addr+3)<<1 | 1),
+#define AFTER(sensor_id) OPCODE_AT,V(sensor_id),OPCODE_AFTER,V(sensor_id),
+#define ALIAS(name,value...) 
+#define AMBER(signal_id) OPCODE_AMBER,V(signal_id),
+#define AT(sensor_id) OPCODE_AT,V(sensor_id),
+#define ATGTE(sensor_id,value) OPCODE_ATGTE,V(sensor_id),OPCODE_PAD,V(value),  
+#define ATLT(sensor_id,value) OPCODE_ATLT,V(sensor_id),OPCODE_PAD,V(value),  
+#define ATTIMEOUT(sensor_id,timeout) OPCODE_ATTIMEOUT1,0,0,OPCODE_ATTIMEOUT2,V(sensor_id),OPCODE_PAD,V(timeout/100L),
+#define AUTOMATION(id, description)  OPCODE_AUTOMATION, V(id), 
+#define AUTOSTART OPCODE_AUTOSTART,0,0,
+#define BROADCAST(msg) PRINT(msg)
+#define CALL(route) OPCODE_CALL,V(route),
+#define CLOSE(id)  OPCODE_CLOSE,V(id),
+#define DEACTIVATE(addr,subaddr) OPCODE_DCCACTIVATE,V(addr<<3 | subaddr<<1),
+#define DEACTIVATEL(addr) OPCODE_DCCACTIVATE,V((addr+3)<<1),
+#define DELAY(ms) ms<30000?OPCODE_DELAYMS:OPCODE_DELAY,V(ms/(ms<30000?1L:100L)),
+#define DELAYMINS(mindelay) OPCODE_DELAYMINS,V(mindelay),
+#define DELAYRANDOM(mindelay,maxdelay) DELAY(mindelay) OPCODE_RANDWAIT,V((maxdelay-mindelay)/100L),
+#define DCC_SIGNAL(id,add,subaddr)
+#define DONE OPCODE_ENDTASK,0,0,
+#define DRIVE(analogpin) OPCODE_DRIVE,V(analogpin),
+#define ELSE OPCODE_ELSE,0,0,
+#define ENDEXRAIL 
+#define ENDIF  OPCODE_ENDIF,0,0,
+#define ENDTASK OPCODE_ENDTASK,0,0,
+#define ESTOP OPCODE_SPEED,V(1), 
+#define EXRAIL 
+#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 FORGET OPCODE_FORGET,0,0,
+#define FREE(blockid) OPCODE_FREE,V(blockid),
+#define FWD(speed) OPCODE_FWD,V(speed),
+#define GREEN(signal_id) OPCODE_GREEN,V(signal_id),
+#define HAL(haltype,params...)
+#define IF(sensor_id) OPCODE_IF,V(sensor_id),
+#define IFAMBER(signal_id) OPCODE_IFAMBER,V(signal_id),
+#define IFCLOSED(turnout_id) OPCODE_IFCLOSED,V(turnout_id),
+#define IFGREEN(signal_id) OPCODE_IFGREEN,V(signal_id),
+#define IFGTE(sensor_id,value) OPCODE_IFGTE,V(sensor_id),OPCODE_PAD,V(value),
+#define IFLT(sensor_id,value) OPCODE_IFLT,V(sensor_id),OPCODE_PAD,V(value),
+#define IFNOT(sensor_id) OPCODE_IFNOT,V(sensor_id),
+#define IFRANDOM(percent) OPCODE_IFRANDOM,V(percent*255/100),
+#define IFRED(signal_id) OPCODE_IFRED,V(signal_id),
+#define IFRESERVE(block) OPCODE_IFRESERVE,V(block),
+#define IFTHROWN(turnout_id) OPCODE_IFTHROWN,V(turnout_id),
+#define IFTIMEOUT OPCODE_IFTIMEOUT,0,0,
+#define INVERT_DIRECTION OPCODE_INVERT_DIRECTION,0,0,
+#define JOIN OPCODE_JOIN,0,0,
+#define KILLALL OPCODE_KILLALL,0,0,
+#define LATCH(sensor_id) OPCODE_LATCH,V(sensor_id),
+#define LCD(id,msg) PRINT(msg)
+#define LCN(msg) PRINT(msg)
+#define MOVETT(id,steps,activity) OPCODE_SERVO,V(id),OPCODE_PAD,V(steps),OPCODE_PAD,V(EXTurntable::activity),OPCODE_PAD,V(0),
+#define ONACTIVATE(addr,subaddr) OPCODE_ONACTIVATE,V(addr<<2|subaddr),
+#define ONACTIVATEL(linear) OPCODE_ONACTIVATE,V(linear+3),
+#define ONAMBER(signal_id) OPCODE_ONAMBER,V(signal_id),
+#define ONCLOSE(turnout_id) OPCODE_ONCLOSE,V(turnout_id),
+#define ONDEACTIVATE(addr,subaddr) OPCODE_ONDEACTIVATE,V(addr<<2|subaddr),
+#define ONDEACTIVATEL(linear) OPCODE_ONDEACTIVATE,V(linear+3),
+#define ONGREEN(signal_id) OPCODE_ONGREEN,V(signal_id),
+#define ONRED(signal_id) OPCODE_ONRED,V(signal_id),
+#define ONTHROW(turnout_id) OPCODE_ONTHROW,V(turnout_id),
+#define PAUSE OPCODE_PAUSE,0,0,
+#define PIN_TURNOUT(id,pin,description...) OPCODE_PINTURNOUT,V(id),OPCODE_PAD,V(pin), 
+#define POM(cv,value) OPCODE_POM,V(cv),OPCODE_PAD,V(value),
+#define POWEROFF OPCODE_POWEROFF,0,0,
+#define POWERON OPCODE_POWERON,0,0,
+#define PRINT(msg) OPCODE_PRINT,V(__COUNTER__ - StringMacroTracker2),
+#define PARSE(msg) PRINT(msg)
+#define READ_LOCO OPCODE_READ_LOCO1,0,0,OPCODE_READ_LOCO2,0,0,
+#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,0,0,
+#define RETURN OPCODE_RETURN,0,0,
+#define REV(speed) OPCODE_REV,V(speed),
+#define ROSTER(cabid,name,funcmap...)
+#define ROUTE(id, description)  OPCODE_ROUTE, V(id), 
+#define SENDLOCO(cab,route) OPCODE_SENDLOCO,V(cab),OPCODE_PAD,V(route),
+#define SEQUENCE(id)  OPCODE_SEQUENCE, V(id), 
+#define SERIAL(msg) PRINT(msg)
+#define SERIAL1(msg) PRINT(msg)
+#define SERIAL2(msg) PRINT(msg)
+#define SERIAL3(msg) PRINT(msg)
+#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 SERVO_SIGNAL(vpin,redpos,amberpos,greenpos)
+#define SERVO_TURNOUT(id,pin,activeAngle,inactiveAngle,profile,description...) OPCODE_SERVOTURNOUT,V(id),OPCODE_PAD,V(pin),OPCODE_PAD,V(activeAngle),OPCODE_PAD,V(inactiveAngle),OPCODE_PAD,V(PCA9685::ProfileType::profile),
+#define SET(pin) OPCODE_SET,V(pin),
+#define SET_TRACK(track,mode)  OPCODE_SET_TRACK,V(TRACK_MODE_##mode  <<8 | TRACK_NUMBER_##track),
+#define SETLOCO(loco) OPCODE_SETLOCO,V(loco),
+#define SIGNAL(redpin,amberpin,greenpin) 
+#define SIGNALH(redpin,amberpin,greenpin) 
+#define SPEED(speed) OPCODE_SPEED,V(speed),
+#define START(route) OPCODE_START,V(route),
+#define STOP OPCODE_SPEED,V(0), 
+#define THROW(id)  OPCODE_THROW,V(id),
+#define TURNOUT(id,addr,subaddr,description...) OPCODE_TURNOUT,V(id),OPCODE_PAD,V(addr),OPCODE_PAD,V(subaddr),
+#define UNJOIN OPCODE_UNJOIN,0,0,
+#define UNLATCH(sensor_id) OPCODE_UNLATCH,V(sensor_id),
+#define VIRTUAL_SIGNAL(id) 
+#define VIRTUAL_TURNOUT(id,description...) OPCODE_PINTURNOUT,V(id),OPCODE_PAD,V(0), 
+#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),
+
+// Build RouteCode
+const int StringMacroTracker2=__COUNTER__;
+const  FLASH  byte RMFT2::RouteCode[] = {
+    #include "myAutomation.h"
+    OPCODE_ENDTASK,0,0,OPCODE_ENDEXRAIL,0,0 };
+
+// Restore normal code LCD & SERIAL  macro
+#undef LCD
+#define LCD   StringFormatter::lcd
+#undef SERIAL
+#define SERIAL  0x0
+#endif

EthernetInterface.cpp

@@ -1,5 +1,10 @@
 /*
- *  © 2020,Gregor Baues,  Chris Harlow. All rights reserved.
+ *  © 2022 Bruno Sanches
+ *  © 2021 Fred Decker
+ *  © 2020-2022 Harald Barth
+ *  © 2020-2021 Chris Harlow
+ *  © 2020 Gregor Baues
+ *  All rights reserved.
  *  
  *  This file is part of DCC-EX/CommandStation-EX
  *
@@ -16,252 +21,80 @@
  *  You should have received a copy of the GNU General Public License
  *  along with CommandStation.  If not, see <https://www.gnu.org/licenses/>.
  * 
- *  Ethernet Interface added by Gregor Baues
  */
-
+#include "defines.h" 
+#if ETHERNET_ON == true
 #include "EthernetInterface.h"
 #include "DIAG.h"
-#include "StringFormatter.h"
+#include "CommandDistributor.h"
+#include "WiThrottle.h"
+#include "DCCTimer.h"
 
-//#include <SPI.h>
-#include <Ethernet.h>
-#include <EthernetUdp.h>
-
-
-// Support Functions
-/**
- * @brief Aquire IP Address from DHCP; if that fails try a statically configured address
- * 
- * @return true 
- * @return false 
- */
-bool EthernetInterface::setupConnection()
-{
-
-    singleton=this;
-    
-    DIAG(F("\nInitialize Ethernet with DHCP:"));
-    server = EthernetServer(LISTEN_PORT); // Ethernet Server listening on default port LISTEN_PORT
-    ip = IPAddress(IP_ADDRESS);                // init with fixed IP address needed to get to the server
-    connected = false;                              // Connection status
-    streamer= new MemStream(buffer, MAX_ETH_BUFFER, MAX_ETH_BUFFER, true);       // streamer who writes the results to the buffer
-
-    if (Ethernet.begin(EthernetInterface::mac) == 0)
-    {
-        DIAG(F("\nFailed to configure Ethernet using DHCP ... Trying with fixed IP"));
-        Ethernet.begin(EthernetInterface::mac, EthernetInterface::ip); // default ip address
-
-        if (Ethernet.hardwareStatus() == EthernetNoHardware)
-        {
-            DIAG(F("\nEthernet shield was not found. Sorry, can't run without hardware. :("));
-            return false;
-        };
-        if (Ethernet.linkStatus() == LinkOFF)
-        {
-            DIAG(F("\nEthernet cable is not connected."));
-            return false;
-        }
-    }
-
-    ip = Ethernet.localIP(); // reassign the obtained ip address
-
-    DIAG(F("\nLocal IP address:      [%d.%d.%d.%d]"), ip[0], ip[1], ip[2], ip[3]);
-    DIAG(F("\nListening on port:     [%d]"), port);
-    dnsip = Ethernet.dnsServerIP();
-    DIAG(F("\nDNS server IP address: [%d.%d.%d.%d] "), ip[0], ip[1], ip[2], ip[3]);
-    return true;
-}
-
-/**
- * @brief Handles command requests recieved via UDP. UDP is a connection less, unreliable protocol as it doesn't maintain state but fast.
- * 
- */
- void EthernetInterface::udpHandler() {
-  singleton->udpHandler2();
- }
- void EthernetInterface::udpHandler2()
-{
-
-    int packetSize = Udp.parsePacket();
-    if (packetSize)
-    {
-        DIAG(F("\nReceived packet of size:[%d]\n"), packetSize);
-        IPAddress remote = Udp.remoteIP();
-        DIAG(F("From:                   [%d.%d.%d.%d:"), remote[0], remote[1], remote[2], remote[3]);
-        char portBuffer[6];
-        DIAG(F("%s]\n"), utoa(Udp.remotePort(), portBuffer, 10)); // DIAG has issues with unsigend int's so go through utoa
-
-        // read the packet into packetBufffer
-        Udp.read(packetBuffer, UDP_TX_PACKET_MAX_SIZE);
-
-        DIAG(F("Command:                [%s]\n"), packetBuffer);
-
-        streamer->flush();
-
-        Udp.beginPacket(Udp.remoteIP(), Udp.remotePort());
-
-        ethParser.parse(streamer, (byte *)packetBuffer, true); // set to true so it is sync cf. WifiInterface
-
-        if (streamer->available() == 0)
-        {
-            DIAG(F("\nNo response\n"));
-        }
-        else
-        {
-            // send the reply
-            DIAG(F("Response: %s\n"), (char *)buffer);
-            Udp.write((char *)buffer);
-            Udp.endPacket();
-        }
-
-        memset(packetBuffer, 0, UDP_TX_PACKET_MAX_SIZE); // reset PacktBuffer
-        return;
-    }
-}
-
-/**
- * @brief Handles command requests recieved via TCP. Supports up to the max# of simultaneous requests which is 8. The connection gets closed as soon as we finished processing
- * 
- */
- void EthernetInterface::tcpHandler()
-{
-  singleton->tcpHandler2();
-}
- void EthernetInterface::tcpHandler2()
-{
-    // get client from the server
-    EthernetClient client = getServer().accept();
-
-    // check for new client
-    if (client)
-    {
-        for (byte i = 0; i < MAX_SOCK_NUM; i++)
-        {
-            if (!clients[i])
-            {
-                // On accept() the EthernetServer doesn't track the client anymore
-                // so we store it in our client array
-                clients[i] = client;
-                break;
-            }
-        }
-    }
-
-    // check for incoming data from all possible clients
-    for (byte i = 0; i < MAX_SOCK_NUM; i++)
-    {
-        if (clients[i] && clients[i].available() > 0)
-        {
-            // read bytes from a client
-            int count = clients[i].read(buffer, MAX_ETH_BUFFER);
-            buffer[count] = '\0'; // terminate the string properly
-            DIAG(F("\nReceived packet of size:[%d]\n"), count);
-            DIAG(F("From Client #:          [%d]\n"), i);
-            DIAG(F("Command:                [%s]\n"), buffer);
-
-            // as we use buffer for recv and send we have to reset the write position
-            streamer->setBufferContentPosition(0, 0);
-
-            ethParser.parse(streamer, buffer, true); // set to true to that the execution in DCC is sync
-
-            if (streamer->available() == 0)
-            {
-                DIAG(F("No response\n"));
-            }
-            else
-            {
-                buffer[streamer->available()] = '\0'; // mark end of buffer, so it can be used as a string later
-                DIAG(F("Response: %s\n"), (char *)buffer);
-                if (clients[i].connected())
-                {
-                    clients[i].write(buffer, streamer->available());
-                }
-            }
-        }
-        // stop any clients which disconnect
-        for (byte i = 0; i < MAX_SOCK_NUM; i++)
-        {
-            if (clients[i] && !clients[i].connected())
-            {
-                DIAG(F("Disconnect client #%d \n"), i);
-                clients[i].stop();
-            }
-        }
-    }
-}
-
-// Class Functions
+EthernetInterface * EthernetInterface::singleton=NULL;
 /**
  * @brief Setup Ethernet Connection
  * 
- * @param pt         Protocol used
- * @param localPort  Port number for the connection
- */
-void EthernetInterface::setup(protocolType pt, uint16_t localPort)
-{
-    DIAG(F("\n++++++ Ethernet Setup In Progress ++++++++\n"));
-    port = localPort;
-    if (setupConnection())
-    {
-        DIAG(F("\nProtocol:              [%s]\n"), pt ? "UDP" : "TCP");
-        switch (pt)
-        {
-        case UDP:
-        {
-            if (Udp.begin(localPort))
-            {
-                connected = true;
-                protocolHandler = udpHandler;
-            }
-            else
-            {
-                DIAG(F("\nUDP client failed to start"));
-                connected = false;
-            }
-            break;
-        };
-        case TCP:
-        {
-            Ethernet.begin(mac, ip);
-            EthernetServer server(localPort);
-            setServer(server);
-            server.begin();
-            connected = true;
-            protocolHandler = tcpHandler;
-            break;
-        };
-        default:
-        {
-            DIAG(F("Unkown Ethernet protocol; Setup failed"));
-            connected = false;
-            return;
-        }
-        }
-    }
-    else
-    {
-        connected = false;
-    };
-    DIAG(F("\n++++++ Ethernet Setup %S ++++++++\n"), connected ? F("OK") : F("FAILED"));
-};
-
-/**
- * @brief Setup Ethernet on default port and user choosen protocol
- * 
- * @param pt Protocol UDP or TCP
- */
-void EthernetInterface::setup(protocolType pt)
-{
-    setup(pt, LISTEN_PORT);
-};
-
-/**
- * @brief Ethernet setup  with defaults TCP / Listen Port
- * 
  */
 void EthernetInterface::setup()
 {
-    setup(TCP, LISTEN_PORT);
+  if (singleton!=NULL) {
+    DIAG(F("Prog Error!"));
+    return;
+  }
+  if ((singleton=new EthernetInterface()))
+    return;
+  DIAG(F("Ethernet not initialized"));
+};
+
+
+/**
+ * @brief Aquire IP Address from DHCP and start server
+ * 
+ * @return true 
+ * @return false 
+ */
+EthernetInterface::EthernetInterface()
+{
+    byte mac[6];
+    DCCTimer::getSimulatedMacAddress(mac);
+    connected=false;
+   
+    #ifdef IP_ADDRESS
+    if (Ethernet.begin(mac, IP_ADDRESS) == 0)
+    #else
+    if (Ethernet.begin(mac) == 0)
+    #endif
+    {
+        DIAG(F("Ethernet.begin FAILED"));
+        return;
+    } 
+    if (Ethernet.hardwareStatus() == EthernetNoHardware) {
+      DIAG(F("Ethernet shield not found or W5100"));
+    }
+  
+    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);
+    }
+    // now we either do have link of we have a W5100
+    // where we do not know if we have link. That's
+    // the reason to now run checkLink.
+    // CheckLinks sets up outboundRing if it does
+    // not exist yet as well.
+    checkLink();
+}
+
+/**
+ * @brief Cleanup any resources
+ * 
+ * @return none
+ */
+EthernetInterface::~EthernetInterface() {
+  delete server;
+  delete outboundRing;
 }
 
 /**
@@ -270,35 +103,131 @@ void EthernetInterface::setup()
  */
 void EthernetInterface::loop()
 {
-    switch (Ethernet.maintain())
-    {
+    if (!singleton || (!singleton->checkLink()))
+      return;
+    
+    switch (Ethernet.maintain()) {
     case 1:
         //renewed fail
-        DIAG(F("\nError: renewed fail"));
-        break;
-
-    case 2:
-        //renewed success
-        DIAG(F("\nRenewed success: "));
-        ip = Ethernet.localIP(); // reassign the obtained ip address
-        DIAG(F("\nLocal IP address:      [%d.%d.%d.%d]"),ip[0], ip[1], ip[2], ip[3]);
-        break;
-
+        DIAG(F("Ethernet Error: renewed fail"));
+        singleton=NULL;
+        return;
     case 3:
         //rebind fail
-        DIAG(F("Error: rebind fail"));
-        break;
-
-    case 4:
-        //rebind success
-        DIAG(F("Rebind success"));
-        ip = Ethernet.localIP(); // reassign the obtained ip address
-        DIAG(F("\nLocal IP address:      [%d.%d.%d.%d]"), ip[0], ip[1], ip[2], ip[3]);
-        break;
-
+        DIAG(F("Ethernet Error: rebind fail"));
+        singleton=NULL;
+        return;
     default:
         //nothing happened
         break;
     }
-    protocolHandler();
+   singleton->loop2();
 }
+
+/**
+ * @brief Checks ethernet link cable status and detects when it connects / disconnects
+ * 
+ * @return true when cable is connected, false otherwise
+ */
+bool EthernetInterface::checkLink() {
+  if (Ethernet.linkStatus() != LinkOFF) { // check for not linkOFF instead of linkON as the W5100 does return LinkUnknown
+    //if we are not connected yet, setup a new server
+    if(!connected) {
+      DIAG(F("Ethernet cable connected"));
+      connected=true;
+      IPAddress ip = Ethernet.localIP(); // reassign the obtained ip address
+      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"), IP_PORT);
+      // only create a outboundRing it none exists, this may happen if the cable
+      // gets disconnected and connected again
+      if(!outboundRing)
+	outboundRing=new RingStream(OUTBOUND_RING_SIZE);
+    }
+    return true;
+  } else { // connected
+    DIAG(F("Ethernet cable disconnected"));
+    connected=false;
+    //clean up any client
+    for (byte socket = 0; socket < MAX_SOCK_NUM; socket++) {
+      if(clients[socket].connected())
+	clients[socket].stop();
+    }
+    // tear down server
+    delete server;
+    server = nullptr;
+    LCD(4,F("IP: None"));
+  }
+  return false;
+}
+
+void EthernetInterface::loop2() {
+    if (!outboundRing) { // no idea to call loop2() if we can't handle outgoing data in it
+      if (Diag::ETHERNET) DIAG(F("No outboundRing"));
+      return;
+    }
+    // get client from the server
+    EthernetClient client = server->accept();
+
+    // check for new client
+    if (client)
+    {
+        if (Diag::ETHERNET) DIAG(F("Ethernet: New client "));
+        byte socket;
+        for (socket = 0; socket < MAX_SOCK_NUM; socket++)
+        {
+            if (!clients[socket])
+            {
+                // On accept() the EthernetServer doesn't track the client anymore
+                // so we store it in our client array
+                if (Diag::ETHERNET) DIAG(F("Socket %d"),socket);
+                clients[socket] = client;
+                break;
+            }
+        }
+        if (socket==MAX_SOCK_NUM) DIAG(F("new Ethernet OVERFLOW")); 
+    }
+
+    // check for incoming data from all possible clients
+    for (byte socket = 0; socket < MAX_SOCK_NUM; socket++)
+    {
+        if (clients[socket]) {
+        
+        int available=clients[socket].available();
+        if (available > 0) {
+            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(",count=%d:%e"), socket,buffer);
+            // execute with data going directly back
+            CommandDistributor::parse(socket,buffer,outboundRing);
+            return; // limit the amount of processing that takes place within 1 loop() cycle. 
+          }
+        }
+    }
+
+    // stop any clients which disconnect
+   for (int socket = 0; socket<MAX_SOCK_NUM; socket++) {
+     if (clients[socket] && !clients[socket].connected()) {
+      clients[socket].stop();
+      CommandDistributor::forget(socket);          
+      if (Diag::ETHERNET)  DIAG(F("Ethernet: disconnect %d "), socket);             
+     }
+    }
+
+    WiThrottle::loop(outboundRing);
+    
+    // handle at most 1 outbound transmission 
+    int socketOut=outboundRing->read();
+    if (socketOut >= MAX_SOCK_NUM) {
+      DIAG(F("Ethernet outboundRing socket=%d error"), socketOut);
+    } else if (socketOut >= 0) {
+      int count=outboundRing->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

@@ -1,5 +1,10 @@
 /*
- *  © 2020,Gregor Baues,  Chris Harlow. All rights reserved.
+ *  © 2021 Neil McKechnie
+ *  © 2021 Mike S
+ *  © 2021 Fred Decker
+ *  © 2020-2021 Chris Harlow
+ *  © 2020 Gregor Baues
+ *  All rights reserved.
  *  
  *  This file is part of DCC-EX/CommandStation-EX
  *
@@ -23,85 +28,44 @@
 #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>
-
-/* 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
- */
+//#include <avr/pgmspace.h>
+#if defined (ARDUINO_TEENSY41)
+ #include <NativeEthernet.h>         //TEENSY Ethernet Treiber
+ #include <NativeEthernetUdp.h>   
+#else
+ #include "Ethernet.h"
+#endif
+#include "RingStream.h"
 
 /**
  * @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
-#define IP_ADDRESS 10, 0, 0, 101                                // Just in case we don't get an adress from DHCP try a static one; make sure 
-                                                                // this one is not used elsewhere and corresponds to your network layout
-#define LISTEN_PORT 3366                                        // default listen port for the server 
-#define MAX_ETH_BUFFER 250
 
-typedef void (*HTTP_CALLBACK)(Print * stream, byte * cmd);
-
-enum protocolType {
-    TCP,
-    UDP
-};
-
-typedef void (*protocolCallback)();
+#define MAX_ETH_BUFFER 512
+#define OUTBOUND_RING_SIZE 2048
 
 class EthernetInterface {
 
-private:
-     EthernetServer server;
-
  public:
-     DCCEXParser  ethParser;
-     bool         connected;
-     byte         mac[6];
-     IPAddress    ip;
-     uint16_t     port;
-     IPAddress    dnsip;
-
-     void setup(protocolType pt, uint16_t lp);        // specific port nummber
-     void setup(protocolType pt);                     // uses default port number
-     void setup();                                    // all defaults (protocol/port)
-
-     protocolCallback protocolHandler;
-
-     void loop();
-
-  private:
-     static EthernetInterface * singleton;
      
-     char packetBuffer[UDP_TX_PACKET_MAX_SIZE];                              // buffer to hold incoming UDP packet,
-     uint8_t buffer[MAX_ETH_BUFFER];                                         // buffer provided to the streamer to be filled with the reply (used by TCP also for the recv)
-     MemStream * streamer;                                                     // streamer who writes the results to the buffer
-     EthernetClient clients[MAX_SOCK_NUM];                                   // accept up to MAX_SOCK_NUM client connections at the same time; This depends on the chipset used on the Shield
-
-     bool setupConnection();
-     static void udpHandler();
-     static void tcpHandler();
-     void udpHandler2();
-     void tcpHandler2();
-     EthernetUDP Udp; 
-    
-     EthernetServer getServer() {
-        return server;
-    };
-     void setServer(EthernetServer s) {
-        server = s;
-    };
+     static void setup();       
+     static void loop();
+   
+ private:
+    static EthernetInterface * singleton;
+    bool connected;
+    EthernetInterface();
+    ~EthernetInterface();
+    void loop2();
+    bool checkLink();
+    EthernetServer * server = NULL;
+    EthernetClient clients[MAX_SOCK_NUM];                // accept up to MAX_SOCK_NUM client connections at the same time; This depends on the chipset used on the Shield
+    uint8_t buffer[MAX_ETH_BUFFER+1];                    // buffer used by TCP for the recv
+    RingStream * outboundRing = NULL;
 };
 
 #endif

FSH.h

@@ -0,0 +1,75 @@
+/*
+ *  © 2022 Paul M. Antoine
+ *  © 2021 Neil McKechnie
+ *  © 2021 Harald Barth
+ *  © 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
+
+#elif defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_ARCH_STM32)
+
+typedef __FlashStringHelper FSH;
+#define GETFLASH(addr) pgm_read_byte(addr)
+// pgm_read_word is buggy if addr is odd but here
+// we do only read well aligned addrs, the others are
+// taken care about in the GET_OPERAND(n) macro in EXRAIL2.cpp.
+#define GETFLASHW(addr) pgm_read_word(addr)
+#ifdef FLASH
+  #undef FLASH
+#endif
+#define FLASH PROGMEM
+
+#else // AVR and AVR compat here
+
+typedef __FlashStringHelper FSH;
+#define GETFLASH(addr) pgm_read_byte_near(addr)
+#define GETFLASHW(addr) pgm_read_word_near(addr)
+#define FLASH PROGMEM
+
+#endif // flash stuff
+#endif // FSH

GITHUB_SHA.h

@@ -1 +1 @@
-#define GITHUB_SHA "9db6d36"
+#define GITHUB_SHA "devel-202211242012Z"

I2CManager.cpp

@@ -0,0 +1,246 @@
+/*
+ *  © 2022 Paul M Antoine
+ *  © 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
+#elif defined(ARDUINO_ARCH_SAMD)
+#include "I2CManager_NonBlocking.h"
+#include "I2CManager_SAMD.h"      // SAMD21 for now... SAMD51 as well later
+#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 +1,293 @@
+/*
+ *  © 2022 Paul M Antoine
+ *  © 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.
+ * 
+ */
+
+// Add following line to config.h to enable Wire library instead of native I2C drivers
+//#define I2C_USE_WIRE
+
+// Add following line to config.h 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;
+#if defined(__arm__)
+  uint32_t _clockSpeed = 32000000L;  // 3.2MHz max on SAMD and STM32
+#else
+  uint32_t _clockSpeed = 400000L;  // 400kHz max on Arduino.
+#endif
+
+  // 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 +1,265 @@
+/*
+ *  © 2022 Paul M Antoine
+ *  © 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)
+// atomic.h isn't available on SAMD, and likely others too...
+#if defined(__AVR__)
+#include <util/atomic.h>
+#elif defined(__arm__)
+// Helper assembly language functions
+static __inline__ uint8_t my_iSeiRetVal(void)
+{
+    __asm__ __volatile__ ("cpsie i" ::);
+    return 1;
+}
+
+static __inline__ uint8_t my_iCliRetVal(void)
+{
+    __asm__ __volatile__ ("cpsid i" ::);
+    return 1;
+}
+
+static __inline__ void my_iRestore(const  uint32_t *__s)
+{
+    uint32_t res = *__s;
+    __asm__ __volatile__ ("MSR primask, %0" : : "r" (res) );
+}
+
+static __inline__ uint32_t my_iGetIReg( void )
+{
+        uint32_t reg;
+        __asm__ __volatile__ ("MRS %0, primask" : "=r" (reg) );
+        return reg;
+}
+// Macros for atomic isolation
+#define MY_ATOMIC_RESTORESTATE uint32_t _sa_saved                           \
+    __attribute__((__cleanup__(my_iRestore))) = my_iGetIReg()
+
+#define ATOMIC()                                                         \
+for ( MY_ATOMIC_RESTORESTATE, _done =  my_iCliRetVal();                   \
+    _done; _done = 0 )
+
+#define ATOMIC_BLOCK(x) ATOMIC()
+#define ATOMIC_RESTORESTATE
+#endif
+#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_SAMD.h

@@ -0,0 +1,244 @@
+/*
+ *  © 2022 Paul M Antoine
+ *  © 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_SAMD_H
+#define I2CMANAGER_SAMD_H
+
+#include <Arduino.h>
+#include "I2CManager.h"
+
+//#include <avr/io.h>
+//#include <avr/interrupt.h>
+#include <wiring_private.h>
+
+/***************************************************************************
+ *  Interrupt handler.
+ *  IRQ handler for SERCOM3 which is the default I2C definition for Arduino Zero
+ *  compatible variants such as the Sparkfun SAMD21 Dev Breakout etc.
+ *  Later we may wish to allow use of an alternate I2C bus, or more than one I2C
+ *  bus on the SAMD architecture 
+ ***************************************************************************/
+#if defined(I2C_USE_INTERRUPTS) && defined(ARDUINO_SAMD_ZERO)
+void SERCOM3_Handler() {
+  I2CManagerClass::handleInterrupt();
+}
+#endif
+
+// Assume SERCOM3 for now - default I2C bus on Arduino Zero and variants of same
+Sercom *s = SERCOM3;
+
+/***************************************************************************
+ *  Set I2C clock speed register.
+ ***************************************************************************/
+void I2CManagerClass::I2C_setClock(uint32_t i2cClockSpeed) {
+
+  // Calculate a rise time appropriate to the requested bus speed
+  int t_rise;
+  if (i2cClockSpeed < 200000L) {
+    i2cClockSpeed = 100000L;
+    t_rise = 1000;
+  } else if (i2cClockSpeed < 800000L) {
+    i2cClockSpeed = 400000L;
+    t_rise = 300;
+  } else if (i2cClockSpeed < 1200000L) {
+    i2cClockSpeed = 1000000L;
+    t_rise = 120;
+  } else {
+    i2cClockSpeed = 100000L;
+    t_rise = 1000;
+  }
+
+  // Disable the I2C master mode and wait for sync
+  s->I2CM.CTRLA.bit.ENABLE = 0 ;
+  while (s->I2CM.SYNCBUSY.bit.ENABLE != 0);
+
+  // Calculate baudrate - using a rise time appropriate for the speed
+  s->I2CM.BAUD.bit.BAUD = SystemCoreClock / (2 * i2cClockSpeed) - 5 - (((SystemCoreClock / 1000000) * t_rise) / (2 * 1000));
+
+  // Enable the I2C master mode and wait for sync
+  s->I2CM.CTRLA.bit.ENABLE = 1 ;
+  while (s->I2CM.SYNCBUSY.bit.ENABLE != 0);
+
+  // Setting bus idle mode and wait for sync
+  s->I2CM.STATUS.bit.BUSSTATE = 1 ;
+  while (s->I2CM.SYNCBUSY.bit.SYSOP != 0);
+
+  return;
+}
+
+/***************************************************************************
+ *  Initialise I2C registers.
+ ***************************************************************************/
+void I2CManagerClass::I2C_init()
+{
+  //Setting clock
+  GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID(GCM_SERCOM3_CORE) | // Generic Clock 0 (SERCOM3)
+                      GCLK_CLKCTRL_GEN_GCLK0 | // Generic Clock Generator 0 is source
+                      GCLK_CLKCTRL_CLKEN ;
+
+  /* Wait for peripheral clock synchronization */
+  while ( GCLK->STATUS.reg & GCLK_STATUS_SYNCBUSY );
+
+  // Software reset the SERCOM
+  s->I2CM.CTRLA.bit.SWRST = 1;
+
+  //Wait both bits Software Reset from CTRLA and SYNCBUSY are equal to 0
+  while(s->I2CM.CTRLA.bit.SWRST || s->I2CM.SYNCBUSY.bit.SWRST);
+
+  // Set master mode and enable SCL Clock Stretch mode (stretch after ACK bit)
+  s->I2CM.CTRLA.reg =  SERCOM_I2CM_CTRLA_MODE( I2C_MASTER_OPERATION )/* |
+                            SERCOM_I2CM_CTRLA_SCLSM*/ ;
+
+  // Enable Smart mode and Quick Command
+  s->I2CM.CTRLB.reg =  SERCOM_I2CM_CTRLB_SMEN | SERCOM_I2CM_CTRLB_QCEN;
+
+#if defined(I2C_USE_INTERRUPTS)
+  // Setting NVIC
+  NVIC_EnableIRQ(SERCOM3_IRQn);
+  NVIC_SetPriority (SERCOM3_IRQn, SERCOM_NVIC_PRIORITY);  // Match default SERCOM priorities
+//  NVIC_SetPriority (SERCOM3_IRQn, 0);  // Set highest priority
+
+  // Enable all interrupts
+  s->I2CM.INTENSET.reg = SERCOM_I2CM_INTENSET_MB | SERCOM_I2CM_INTENSET_SB | SERCOM_I2CM_INTENSET_ERROR;
+#endif
+
+  // Calculate baudrate and set default rate for now
+  s->I2CM.BAUD.bit.BAUD = SystemCoreClock / ( 2 * I2C_FREQ) - 7 / (2 * 1000);
+
+  // Enable the I2C master mode and wait for sync
+  s->I2CM.CTRLA.bit.ENABLE = 1 ;
+  while (s->I2CM.SYNCBUSY.bit.ENABLE != 0);
+
+  // Setting bus idle mode and wait for sync
+  s->I2CM.STATUS.bit.BUSSTATE = 1 ;
+  while (s->I2CM.SYNCBUSY.bit.SYSOP != 0);
+
+  // Set SDA/SCL pins as outputs and enable pullups, at present we assume these are
+  // the default ones for SERCOM3 (see assumption above)
+  pinPeripheral(PIN_WIRE_SDA, g_APinDescription[PIN_WIRE_SDA].ulPinType);
+  pinPeripheral(PIN_WIRE_SCL, g_APinDescription[PIN_WIRE_SCL].ulPinType);
+
+  // Enable the SCL and SDA pins on the sercom: includes increased driver strength,
+  // pull-up resistors and pin multiplexer
+	PORT->Group[g_APinDescription[PIN_WIRE_SCL].ulPort].PINCFG[g_APinDescription[PIN_WIRE_SCL].ulPin].reg =  
+		PORT_PINCFG_DRVSTR | PORT_PINCFG_PULLEN | PORT_PINCFG_PMUXEN;  
+  PORT->Group[g_APinDescription[PIN_WIRE_SDA].ulPort].PINCFG[g_APinDescription[PIN_WIRE_SDA].ulPin].reg = 
+		PORT_PINCFG_DRVSTR | PORT_PINCFG_PULLEN | PORT_PINCFG_PMUXEN;
+}
+
+/***************************************************************************
+ *  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 (s->I2CM.STATUS.bit.BUSSTATE == 0x2);
+
+  // If anything to send, initiate write.  Otherwise initiate read.
+  if (operation == OPERATION_READ || ((operation == OPERATION_REQUEST) && !bytesToSend))
+  {
+    // Send start and address with read/write flag or'd in
+    s->I2CM.ADDR.bit.ADDR = (currentRequest->i2cAddress << 1) | 1;
+  }
+  else {
+    // Wait while the I2C bus is BUSY
+    while (s->I2CM.STATUS.bit.BUSSTATE != 0x1);
+    s->I2CM.ADDR.bit.ADDR = (currentRequest->i2cAddress << 1ul) | 0;
+  }
+}
+
+/***************************************************************************
+ *  Initiate a stop bit for transmission (does not interrupt)
+ ***************************************************************************/
+void I2CManagerClass::I2C_sendStop() {
+  s->I2CM.CTRLB.bit.CMD = 3; // Stop condition
+}
+
+/***************************************************************************
+ *  Close I2C down
+ ***************************************************************************/
+void I2CManagerClass::I2C_close() {
+  I2C_sendStop();
+}
+
+/***************************************************************************
+ *  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 (s->I2CM.STATUS.bit.ARBLOST) {
+    // Arbitration lost, restart
+    I2C_sendStart();   // Reinitiate request
+  } else if (s->I2CM.STATUS.bit.BUSERR) {
+    // Bus error
+    state = I2C_STATUS_BUS_ERROR;
+  } else if (s->I2CM.INTFLAG.bit.MB) {
+    // Master write completed
+    if (s->I2CM.STATUS.bit.RXNACK) {
+      // Nacked, send stop.
+      I2C_sendStop();
+      state = I2C_STATUS_NEGATIVE_ACKNOWLEDGE;
+    } else if (bytesToSend) {
+      // Acked, so send next byte
+      if (currentRequest->operation == OPERATION_SEND_P)
+        s->I2CM.DATA.bit.DATA = GETFLASH(currentRequest->writeBuffer + (txCount++));
+      else
+        s->I2CM.DATA.bit.DATA = currentRequest->writeBuffer[txCount++];
+      bytesToSend--;
+    } else if (bytesToReceive) {
+      // Last sent byte acked and no more to send.  Send repeated start, address and read bit.
+        s->I2CM.ADDR.bit.ADDR = (currentRequest->i2cAddress << 1) | 1;
+    } else {
+      // No more data to send/receive. Initiate a STOP condition.
+      I2C_sendStop();
+      state = I2C_STATUS_OK; // Done
+    }
+  } else if (s->I2CM.INTFLAG.bit.SB) {
+    // Master read completed without errors
+    if (bytesToReceive) {
+      currentRequest->readBuffer[rxCount++] = s->I2CM.DATA.bit.DATA;  // Store received byte
+      bytesToReceive--;
+    } else { 
+      // Buffer full, issue nack/stop
+      s->I2CM.CTRLB.bit.ACKACT = 1;
+      I2C_sendStop();
+      state = I2C_STATUS_OK;
+    }
+    if (bytesToReceive) {
+      // PMA - I think Smart Mode means we have nothing to do...
+      // More bytes to receive, issue ack and start another read
+    }
+    else
+    {
+      // Transaction finished, issue NACK and STOP.
+      s->I2CM.CTRLB.bit.ACKACT = 1;
+      I2C_sendStop();
+      state = I2C_STATUS_OK;
+    }
+  }
+}
+
+#endif /* I2CMANAGER_SAMD_H */

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.
+ * The read/write/write_P functions return I2C_STATUS_OK always, and the 
+ * completion status of the operation is in the request block, as for
+ * the non-blocking version.
+ ***************************************************************************/
+void I2CManagerClass::queueRequest(I2CRB *req) {
+  switch (req->operation) {
+    case OPERATION_READ:
+      read(req->i2cAddress, req->readBuffer, req->readLen, NULL, 0, req);
+      break;
+    case OPERATION_SEND:
+      write(req->i2cAddress, req->writeBuffer, req->writeLen, req);
+      break;
+    case OPERATION_SEND_P:
+      write_P(req->i2cAddress, req->writeBuffer, req->writeLen, req);
+      break;
+    case OPERATION_REQUEST:
+      read(req->i2cAddress, req->readBuffer, req->readLen, req->writeBuffer, req->writeLen, req);
+      break;
+  }
+}
+
+/***************************************************************************
+ *  Loop function, for general background work
+ ***************************************************************************/
+void I2CManagerClass::loop() {}
+
+// Loop function
+void I2CManagerClass::checkForTimeout() {}
+
+
+#endif

IODevice.cpp

@@ -0,0 +1,547 @@
+/*
+ *  © 2021 Neil McKechnie
+ *  © 2021 Harald Barth
+ *  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"
+#include "DCCTimer.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 exrailHalSetup();
+
+//==================================================================================================================
+// 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() {
+  // 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.
+  
+  // This is done first so that the following defaults will detect an overlap and not
+  // create something that conflicts with the users vpin definitions. 
+  if (halSetup)
+    halSetup();
+
+  // include any HAL devices defined in exrail. 
+  if (exrailHalSetup)
+    exrailHalSetup();
+
+  // Initialise the IO subsystem defaults
+  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;
+}
+
+// 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 -1023;
+}
+int IODevice::configureAnalogIn(VPIN vpin) {
+  for (IODevice *dev = _firstDevice; dev != 0; dev = dev->_nextDevice) {
+    if (dev->owns(vpin)) 
+      return dev->_configureAnalogIn(vpin);
+  }
+#ifdef DIAG_IO
+  DIAG(F("IODevice::configureAnalogIn(): Vpin %d not found!"), (int)vpin);
+#endif
+  return -1023;
+}
+
+// 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;
+}
+
+// Private helper function to check for vpin overlap. Run during setup only.
+// returns true if pins DONT overlap with existing device
+bool IODevice::checkNoOverlap(VPIN firstPin, uint8_t nPins, uint8_t i2cAddress) {
+#ifdef DIAG_IO
+  DIAG(F("Check no overlap %d %d 0x%x"), firstPin,nPins,i2cAddress);
+#endif
+  VPIN lastPin=firstPin+nPins-1;
+  for (IODevice *dev = _firstDevice; dev != 0; dev = dev->_nextDevice) {
+    
+    // check for pin range overlaps (verbose but compiler will fix that)  
+    VPIN firstDevPin=dev->_firstVpin;
+    VPIN lastDevPin=firstDevPin+dev->_nPins-1;
+    bool noOverlap= firstPin>lastDevPin || lastPin<firstDevPin;
+    if (!noOverlap) {
+        DIAG(F("WARNING HAL Overlap definition of pins  %d to %d ignored."),
+            firstPin, lastPin);
+        return false;
+    } 
+  
+    // Check for overlapping I2C address
+    if (i2cAddress && dev->_I2CAddress==i2cAddress) {
+      DIAG(F("WARNING HAL Overlap. i2c Addr 0x%x ignored."),i2cAddress);
+      return false;
+    } 
+  }
+  return true;  // no overlaps... OK to go on with constructor
+}
+  
+
+//==================================================================================================================
+// 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) {
+  return ADCee::read(vpin);
+}
+int IODevice::configureAnalogIn(VPIN vpin) {
+  return ADCee::init(vpin);
+}
+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) {
+  if (vpin > 255) return -1023;
+  uint8_t pin = vpin;
+  int value = ADCee::read(pin);
+
+  #ifdef DIAG_IO
+  DIAG(F("Arduino Read Pin:%d Value:%d"), pin, value);
+  #endif
+  return value;
+}
+int ArduinoPins::_configureAnalogIn(VPIN vpin) {
+  if (vpin > 255) return -1023;
+  uint8_t 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);
+  }
+  int value = ADCee::init(pin);
+  #ifdef DIAG_IO
+  DIAG(F("configureAnalogIn 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 +1,412 @@
+/*
+ *  © 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);
+  static int configureAnalogIn(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;
+    _I2CAddress=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;
+  };
+  virtual int _configureAnalogIn(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;
+  uint8_t _I2CAddress;
+  // 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;
+    
+  // Method to check if pins will overlap before creating new device. 
+  static bool checkNoOverlap(VPIN firstPin, uint8_t nPins=1, uint8_t i2cAddress=0);
+
+  // 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);
+  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:
+  // Constructor
+  PCA9685(VPIN vpin, int nPins, uint8_t I2CAddress);
+  // 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;
+  
+
+  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);
+
+private:
+  // Constructor
+  DCCAccessoryDecoder(VPIN firstVpin, int nPins, int DCCAddress, int DCCSubaddress);
+  // 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));
+  }
+  
+  static void fastWriteDigital(uint8_t pin, uint8_t value);
+  static bool fastReadDigital(uint8_t pin);
+
+private:
+  // Constructor
+  ArduinoPins(VPIN firstVpin, int nPins);
+
+  // 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;
+  int _configureAnalogIn(VPIN vpin) override;
+  void _display() override;
+
+
+  uint8_t *_pinPullups;
+  uint8_t *_pinModes; // each bit is 1 for output, 0 for input
+  uint8_t *_pinInUse; 
+};
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////
+/*
+ * IODevice subclass for EX-Turntable.
+ */
+ 
+class EXTurntable : public IODevice {
+public:
+  static void create(VPIN firstVpin, int nPins, uint8_t I2CAddress);
+  // Constructor
+  EXTurntable(VPIN firstVpin, int nPins, uint8_t I2CAddress);
+  enum ActivityNumber : uint8_t {
+    Turn = 0,             // Rotate turntable, maintain phase
+    Turn_PInvert = 1,     // Rotate turntable, invert phase
+    Home = 2,             // Initiate homing
+    Calibrate = 3,        // Initiate calibration sequence
+    LED_On = 4,           // Turn LED on
+    LED_Slow = 5,         // Set LED to a slow blink
+    LED_Fast = 6,         // Set LED to a fast blink
+    LED_Off = 7,          // Turn LED off
+    Acc_On = 8,           // Turn accessory pin on
+    Acc_Off = 9,          // Turn accessory pin off
+  };
+
+private:
+  // Device-specific write function.
+  void _begin() override;
+  void _loop(unsigned long currentMicros) override;
+  int _read(VPIN vpin) override;
+  void _writeAnalogue(VPIN vpin, int value, uint8_t activity, uint16_t duration) override;
+  void _display() override;
+  uint8_t _stepperStatus;
+};
+
+/////////////////////////////////////////////////////////////////////////////////////////////////////
+
+#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:
+  static void create(VPIN firstVpin, int nPins, uint8_t i2cAddress) {
+    if (checkNoOverlap(firstVpin,nPins,i2cAddress)) new ADS111x(firstVpin, nPins, i2cAddress);
+  }
+private:
+  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);
+  }
+  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 +1,68 @@
+/*
+ *  © 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 firstVpin, int nPins, int DCCAddress, int DCCSubaddress) {
+  if (checkNoOverlap(firstVpin,nPins)) new DCCAccessoryDecoder(firstVpin, 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;
+#if defined(HAL_ACCESSORY_COMMAND_REVERSE)
+  state = !state;
+#ifdef DIAG_IO
+  DIAG(F("DCC Write Linear Address:%d State:%d (inverted)"), packedAddress, state);
+#endif
+#else
+#ifdef DIAG_IO
+  DIAG(F("DCC Write Linear Address:%d State:%d"), packedAddress, state);
+#endif
+#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 +1,291 @@
+/*
+ *  © 2022, 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 1-2999 to the first pin (3500) will play the numbered file from the SD card;
+ * Writing an analogue value 0 to the first pin (3500) will stop the file playing;
+ * Writing an analogue value 0-30 to the second pin (3501) will set the volume;
+ * Writing a digital value of 1 to a pin will play the file corresponding to that pin, e.g.
+   the first file will be played by setting pin 3500, the second by setting pin 3501 etc.;
+ * Writing a digital value of 0 to any pin will stop the player;
+ * 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 (file 1) on the SD card
+ *   SET(3501)      -- starts playing the second file (file 2) 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(3500,2,Instant)  -- plays file 2 at current volume
+ *   SERVO(3501,20,Instant)   -- 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.
+ * 
+ * Files on the SD card are numbered according to their order in the directory on the 
+ * card (as listed by the DIR command in Windows).  This may not match the order of the files 
+ * as displayed by Windows File Manager, which sorts the file names.  It is suggested that
+ * files be copied into an empty SDcard in the desired order, one at a time.
+ */
+
+#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
+
+  // When two commands are sent in quick succession, the device sometimes 
+  // fails to execute one.  A delay is required between successive commands.
+  // This could be implemented by buffering commands and outputting them
+  // from the loop() function, but it would somewhat complicate the 
+  // driver.  A simpler solution is to output a number of NUL pad characters
+  // between successive command strings if there isn't sufficient elapsed time
+  // between them.  At 9600 baud, each pad character takes approximately
+  // 1ms to complete.  Experiments indicate that the minimum number of pads
+  // for reliable operation is 17.  This gives 17.7ms between the end of one
+  // command and the beginning of the next, or 28ms between successive commands
+  // being completed.  I've allowed 20 characters, which is almost 21ms.
+  const int numPadCharacters = 20;  // Number of pad characters between commands
+  
+public:
+ 
+  static void create(VPIN firstVpin, int nPins, HardwareSerial &serial) {
+    if (checkNoOverlap(firstVpin,nPins)) new DFPlayer(firstVpin, nPins, serial);
+  }
+
+protected:
+  // Constructor
+  DFPlayer(VPIN firstVpin, int nPins, HardwareSerial &serial) :
+    IODevice(firstVpin, nPins),
+    _serial(&serial) 
+  {
+    addDevice(this);
+  }
+
+  void _begin() override {
+    _serial->begin(9600, SERIAL_8N1); // 9600baud, no parity, 1 stop bit
+    // Flush any data in input queue
+    while (_serial->available()) _serial->read();
+    _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 "7E FF 06 3D xx xx xx xx xx EF"
+    while (_serial->available()) {
+      int c = _serial->read();
+      if (c == 0x7E && _inputIndex == 0) 
+        _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 5 seconds
+    if (_deviceState == DEVSTATE_INITIALISING && currentMicros - _commandSendTime > 5000000UL) {
+      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((uint8_t)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)
+  {
+    unsigned long currentMillis = millis();
+    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);
+
+    // Check how long since the last command was sent.
+    // Each character takes approx 1ms at 9600 baud
+    unsigned long minimumGap = numPadCharacters + sizeof(out);
+    if (currentMillis - _commandSendTime < minimumGap) {
+      // Output some pad characters to add an
+      // artificial delay between commands
+      for (int i=0; i<numPadCharacters; i++) 
+        _serial->write(0);
+    }
+
+    // Now output the command
+    _serial->write(out, sizeof(out));
+    _commandSendTime = currentMillis;
+  }
+
+  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_EXTurntable.h

@@ -0,0 +1,121 @@
+/*
+ *  © 2021, Peter Cole. 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/>.
+*/
+
+/*
+* The IO_EXTurntable device driver is used to control a turntable via an Arduino with a stepper motor over I2C.
+*
+* The EX-Turntable code lives in a separate repo (https://github.com/DCC-EX/Turntable-EX) and contains the stepper motor logic.
+*
+* This device driver sends a step position to Turntable-EX to indicate the step position to move to using either of these commands:
+* <D TT vpin steps activity> in the serial console
+* MOVETT(vpin, steps, activity) in EX-RAIL
+* Refer to the documentation for further information including the valid activities.
+*/
+
+#ifndef IO_EXTurntable_h
+#define IO_EXTurntable_h
+
+#include "IODevice.h"
+#include "I2CManager.h"
+#include "DIAG.h"
+
+void EXTurntable::create(VPIN firstVpin, int nPins, uint8_t I2CAddress) {
+  new EXTurntable(firstVpin, nPins, I2CAddress);
+}
+
+// Constructor
+EXTurntable::EXTurntable(VPIN firstVpin, int nPins, uint8_t I2CAddress) {
+  _firstVpin = firstVpin;
+  _nPins = nPins;
+  _I2CAddress = I2CAddress;
+  addDevice(this);
+}
+
+// Initialisation of TurntableEX
+void EXTurntable::_begin() {
+  I2CManager.begin();
+  I2CManager.setClock(1000000);
+  if (I2CManager.exists(_I2CAddress)) {
+#ifdef DIAG_IO
+    _display();
+#endif
+  } else {
+    _deviceState = DEVSTATE_FAILED;
+  }
+}
+
+// Processing loop to obtain status of stepper
+// 0 = finished moving and in correct position
+// 1 = still moving
+void EXTurntable::_loop(unsigned long currentMicros) {
+  uint8_t readBuffer[1];
+  I2CManager.read(_I2CAddress, readBuffer, 1);
+  _stepperStatus = readBuffer[0];
+  // DIAG(F("Turntable-EX returned status: %d"), _stepperStatus);
+  delayUntil(currentMicros + 500000);  // Wait 500ms before checking again, turntables turn slowly
+}
+
+// Read returns status as obtained in our loop.
+// Return false if our status value is invalid.
+int EXTurntable::_read(VPIN vpin) {
+  if (_deviceState == DEVSTATE_FAILED) return 0;
+  // DIAG(F("_read status: %d"), _stepperStatus);
+  if (_stepperStatus > 1) {
+    return false;
+  } else {
+    return _stepperStatus;
+  }
+}
+
+// writeAnalogue to send the steps and activity to Turntable-EX.
+// Sends 3 bytes containing the MSB and LSB of the step count, and activity.
+// value contains the steps, bit shifted to MSB + LSB.
+// activity contains the activity flag as per this list:
+// 
+// Turn = 0,             // Rotate turntable, maintain phase
+// Turn_PInvert = 1,     // Rotate turntable, invert phase
+// Home = 2,             // Initiate homing
+// Calibrate = 3,        // Initiate calibration sequence
+// LED_On = 4,           // Turn LED on
+// LED_Slow = 5,         // Set LED to a slow blink
+// LED_Fast = 6,         // Set LED to a fast blink
+// LED_Off = 7,          // Turn LED off
+// Acc_On = 8,           // Turn accessory pin on
+// Acc_Off = 9           // Turn accessory pin off
+void EXTurntable::_writeAnalogue(VPIN vpin, int value, uint8_t activity, uint16_t duration) {
+  if (_deviceState == DEVSTATE_FAILED) return;
+  uint8_t stepsMSB = value >> 8;
+  uint8_t stepsLSB = value & 0xFF;
+#ifdef DIAG_IO
+  DIAG(F("TurntableEX WriteAnalogue Vpin:%d Value:%d Activity:%d Duration:%d"),
+    vpin, value, activity, duration);
+  DIAG(F("I2CManager write I2C Address:%d stepsMSB:%d stepsLSB:%d activity:%d"),
+    _I2CAddress, stepsMSB, stepsLSB, activity);
+#endif
+  _stepperStatus = 1;     // Tell the device driver Turntable-EX is busy
+  I2CManager.write(_I2CAddress, 3, stepsMSB, stepsLSB, activity);
+}
+
+// Display Turnetable-EX device driver info.
+void EXTurntable::_display() {
+  DIAG(F("TurntableEX I2C:x%x Configured on Vpins:%d-%d %S"), _I2CAddress, (int)_firstVpin, 
+    (int)_firstVpin+_nPins-1, (_deviceState==DEVSTATE_FAILED) ? F("OFFLINE") : F(""));
+}
+
+#endif

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) {
+  if (checkNoOverlap(firstVpin,nPins)) 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:
+  static void create(VPIN firstVpin, int nPins, HardwareSerial *serial, unsigned long baud);  
+
+protected:
+  IO_ExampleSerial(VPIN firstVpin, int nPins, HardwareSerial *serial, unsigned long baud);
+  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 +1,253 @@
+/*
+ *  © 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
+ 
+  // 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;
+#if defined(ARDUINO_ARCH_ESP32)
+  // workaround: Has somehow no min function for all types
+  static inline T min(T a, int b) { return a < b ? a : b; };
+#endif
+};
+
+// 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 +1,189 @@
+/*
+ *  © 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:
+ 
+  // Static create function provides alternative way to create object
+  static void create(VPIN vpin, int trigPin, int echoPin, uint16_t onThreshold, uint16_t offThreshold) {
+    if (checkNoOverlap(vpin))
+        new HCSR04(vpin, trigPin, echoPin, onThreshold, offThreshold);
+  }
+
+protected:
+  // 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);
+  }
+ // _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 = 0, 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 +1,101 @@
+/*
+ *  © 2022 Paul M Antoine
+ *  © 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"
+
+class MCP23008 : public GPIOBase<uint8_t> {
+public:
+  static void create(VPIN firstVpin, uint8_t nPins, uint8_t I2CAddress, int interruptPin=-1) {
+    if (checkNoOverlap(firstVpin, nPins,I2CAddress)) new MCP23008(firstVpin, nPins, I2CAddress, interruptPin);
+  }
+
+private:
+  // Constructor
+  MCP23008(VPIN firstVpin, uint8_t nPins, uint8_t I2CAddress, int interruptPin=-1)
+    : GPIOBase<uint8_t>((FSH *)F("MCP23008"), firstVpin, min(nPins, (uint8_t)8), I2CAddress, interruptPin) {
+
+    requestBlock.setRequestParams(_I2CAddress, inputBuffer, sizeof(inputBuffer),
+      outputBuffer, sizeof(outputBuffer));
+    outputBuffer[0] = REG_GPIO;
+  }
+  
+  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 +1,111 @@
+/*
+ *  © 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) {
+    if (checkNoOverlap(vpin, nPins, I2CAddress)) new MCP23017(vpin, min(nPins,16), I2CAddress, interruptPin);
+  }
+
+private:  
+  // 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;
+  }
+  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 +1,276 @@
+/*
+ *  © 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) {
+  if (checkNoOverlap(firstVpin, nPins,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) {
+  #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 {
+     /* simulate digital pin on PWM */
+      _writeAnalogue(vpin, value ? 4095 : 0, Instant | NoPowerOff, 0);     
+      }
+}
+
+// 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) {
+  #ifdef DIAG_IO
+  DIAG(F("PCA9685 WriteAnalogue Vpin:%d Value:%d Profile:%d Duration:%d %S"), 
+    vpin, value, profile, duration, _deviceState == DEVSTATE_FAILED?F("DEVSTATE_FAILED"):F(""));
+  #endif
+  if (_deviceState == DEVSTATE_FAILED) return;
+  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 = 4095;
+    s->inactivePosition = 0;
+    s->currentPosition = value;
+    s->profile = Instant | NoPowerOff;  // 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 +1,103 @@
+/*
+ *  © 2022 Paul M Antoine
+ *  © 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) {
+    if (checkNoOverlap(firstVpin, nPins,I2CAddress)) new PCF8574(firstVpin, nPins, I2CAddress, interruptPin);
+  }
+
+private:
+  PCF8574(VPIN firstVpin, uint8_t nPins, uint8_t I2CAddress, int interruptPin=-1)
+    : GPIOBase<uint8_t>((FSH *)F("PCF8574"), firstVpin, min(nPins, (uint8_t)8), I2CAddress, interruptPin) 
+  {
+    requestBlock.setReadParams(_I2CAddress, inputBuffer, 1);
+  }
+  
+  // 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 +1,300 @@
+/*
+ *  © 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:
+  static void create(VPIN firstVpin, int nPins, uint8_t i2cAddress, uint16_t onThreshold, uint16_t offThreshold, VPIN xshutPin = VPIN_NONE) {
+     if (checkNoOverlap(firstVpin, nPins,i2cAddress)) new VL53L0X(firstVpin, nPins, i2cAddress, onThreshold, offThreshold, xshutPin);
+  }
+
+protected:
+  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);
+  }
+  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 +1,76 @@
+/*
+ *  © 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');
+      id = 0;
+    }
+    else if (ch == 'y' || ch == 'Y') { // Turnout opcodes
+      if (Diag::LCN) DIAG(F("LCN IN %d%c"),id,(char)ch);
+      Turnout::setClosed(id,ch=='y');
+      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

@@ -1,7 +1,9 @@
 /*
- *  © 2020, Harald Barth
+ *  © 2021 Harald Barth
+ *  © 2021 Fred Decker
+ *  All rights reserved.
  *  
- *  This file is part of Asbelos DCC-EX
+ *  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
@@ -16,27 +18,19 @@
  *  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>
 
-#include "freeMemory.h"
+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;
+};
 
-// thanks go to  https://github.com/mpflaga/Arduino-MemoryFree
-#if defined(__arm__)
-extern "C" char* sbrk(int);
-#elif defined(__AVR__)
-extern char *__brkval;
-extern char *__malloc_heap_start;
-#else
-#error Unsupported board type
 #endif
-
-
-int freeMemory() {
-  char top;
-#if defined(__arm__)
-  return &top - reinterpret_cast<char*>(sbrk(0));
-#elif defined(__AVR__)
-  return __brkval ? &top - __brkval : &top - __malloc_heap_start;
-#else
-#error bailed out alredy above
-#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

@@ -1,7 +1,12 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2022 Paul M Antoine
+ *  © 2021 Mike S
+ *  © 2021 Fred Decker
+ *  © 2020-2022 Harald Barth
+ *  © 2020-2021 Chris Harlow
+ *  All rights reserved.
  *  
- *  This file is part of Asbelos DCC API
+ *  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
@@ -18,67 +23,374 @@
  */
 #include <Arduino.h>
 #include "MotorDriver.h"
-#include "AnalogReadFast.h"
+#include "DCCWaveform.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 "ESP32-fixes.h"
 #endif
-    
-MotorDriver::MotorDriver(byte power_pin, byte signal_pin, byte signal_pin2, byte brake_pin, 
+
+bool MotorDriver::commonFaultPin=false;
+
+volatile portreg_t shadowPORTA;
+volatile portreg_t shadowPORTB;
+volatile portreg_t shadowPORTC;
+
+MotorDriver::MotorDriver(int16_t 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;
-   signalPin=signal_pin;
-   signalPin2=signal_pin2;
-   brakePin=brake_pin;
-   currentPin=current_pin;
-   senseFactor=sense_factor;
-   faultPin=fault_pin;
-   tripMilliamps=trip_milliamps;
-   rawCurrentTripValue=(int)(trip_milliamps / sense_factor);
-  pinMode(powerPin, OUTPUT);
-  pinMode(brakePin, OUTPUT);
-  pinMode(signalPin, OUTPUT);
-  if (signalPin2 != UNUSED_PIN) pinMode(signalPin2, OUTPUT);
-  pinMode(currentPin, INPUT);
-  if (faultPin != UNUSED_PIN) pinMode(faultPin, INPUT);
-}
-
-void MotorDriver::setPower(bool on) {
-  WritePin(powerPin, on ? HIGH : LOW);
-}
-void MotorDriver::setBrake( bool on) {
-  WritePin(brakePin, on ? HIGH : LOW);
-}
-
-void MotorDriver::setSignal( bool high) {
-  WritePin(signalPin, high ? HIGH : LOW);
-  if (signalPin2 != UNUSED_PIN) WritePin(signalPin2, high ? LOW : HIGH);
-}
-
-
-int MotorDriver::getCurrentRaw() {
-  if (faultPin != UNUSED_PIN && ReadPin(faultPin) == LOW && ReadPin(powerPin) == HIGH)
-      return (int)(32000/senseFactor);
+  powerPin=power_pin;
+  invertPower=power_pin < 0;
+  if (invertPower) {
+    powerPin = 0-power_pin;
+    IODevice::write(powerPin,HIGH);// set to OUTPUT and off
+  } else {
+    powerPin = power_pin;
+    IODevice::write(powerPin,LOW);// set to OUTPUT and off
+  }
   
-  // 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);
+  signalPin=signal_pin;
+  getFastPin(F("SIG"),signalPin,fastSignalPin);
+  pinMode(signalPin, OUTPUT);
+
+  fastSignalPin.shadowinout = NULL;
+  if (HAVE_PORTA(fastSignalPin.inout == &PORTA)) {
+    DIAG(F("Found PORTA pin %d"),signalPin);
+    fastSignalPin.shadowinout = fastSignalPin.inout;
+    fastSignalPin.inout = &shadowPORTA;
+  }
+  if (HAVE_PORTB(fastSignalPin.inout == &PORTB)) {
+    DIAG(F("Found PORTB pin %d"),signalPin);
+    fastSignalPin.shadowinout = fastSignalPin.inout;
+    fastSignalPin.inout = &shadowPORTB;
+  }
+  if (HAVE_PORTC(fastSignalPin.inout == &PORTC)) {
+    DIAG(F("Found PORTC pin %d"),signalPin);
+    fastSignalPin.shadowinout = fastSignalPin.inout;
+    fastSignalPin.inout = &shadowPORTC;
+  }
+
+  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);
+    // if brake is used for railcom  cutout we need to do PORTX register trick here as well
+    pinMode(brakePin, OUTPUT);
+    setBrake(true);  // start with brake on in case we hace DC stuff going on
+  }
+  else brakePin=UNUSED_PIN;
+  
+  currentPin=current_pin;
+  if (currentPin!=UNUSED_PIN) {
+    senseOffset = ADCee::init(currentPin);
+  }
+
+  faultPin=fault_pin;
+  if (faultPin != UNUSED_PIN) {
+    getFastPin(F("FAULT"),faultPin, 1 /*input*/, fastFaultPin);
+    pinMode(faultPin, INPUT);
+  }
+
+  // This conversion performed at compile time so the remainder of the code never needs
+  // float calculations or libraray code. 
+  senseFactorInternal=sense_factor * senseScale; 
+  tripMilliamps=trip_milliamps;
+  rawCurrentTripValue=mA2raw(trip_milliamps);
+
+  if (rawCurrentTripValue + senseOffset > ADCee::ADCmax()) {
+    // This would mean that the values obtained from the ADC never
+    // can reach the trip value. So independent of the current, the
+    // short circuit protection would never trip. So we adjust the
+    // trip value so that it is tiggered when the ADC reports it's
+    // maximum value instead.
+
+    //    DIAG(F("Changing short detection value from %d to %d mA"),
+    // raw2mA(rawCurrentTripValue), raw2mA(ADCee::ADCmax()-senseOffset));
+    rawCurrentTripValue=ADCee::ADCmax()-senseOffset;
+  }
+
+  if (currentPin==UNUSED_PIN) 
+    DIAG(F("** WARNING ** No current or short detection"));
+  else  {
+    DIAG(F("CurrentPin=A%d, Offset=%d, TripValue=%d"),
+    currentPin-A0, senseOffset,rawCurrentTripValue);
+
+    // self testing diagnostic for the non-float converters... may be removed when happy
+    //  DIAG(F("senseFactorInternal=%d raw2mA(1000)=%d mA2Raw(1000)=%d"),
+    //   senseFactorInternal, raw2mA(1000),mA2raw(1000));
+  }
+
+  // prepare values for current detection
+  sampleDelay = 0;
+  lastSampleTaken = millis();
+  progTripValue = mA2raw(TRIP_CURRENT_PROG); 
+
+}
+
+bool MotorDriver::isPWMCapable() {
+    return (!dualSignal) && DCCTimer::isPWMPin(signalPin); 
+}
+
+
+void MotorDriver::setPower(POWERMODE mode) {
+  bool on=mode==POWERMODE::ON;
+  if (on) {
+    noInterrupts();
+    IODevice::write(powerPin,invertPower ? LOW : HIGH);
+    interrupts();
+    if (isProgTrack)
+      DCCWaveform::progTrack.clearResets();
+  }
+  else {
+      noInterrupts();
+      IODevice::write(powerPin,invertPower ? HIGH : LOW);
+      interrupts();
+  }
+  powerMode=mode; 
+}
+
+// setBrake applies brake if on == true. So to get
+// voltage from the motor bride one needs to do a
+// setBrake(false).
+// If the brakePin is negative that means the sense
+// of the brake pin on the motor bridge is inverted
+// (HIGH == release brake) and setBrake does
+// compensate for that.
+//
+void MotorDriver::setBrake(bool on, bool interruptContext) {
+  if (brakePin == UNUSED_PIN) return;
+  if (!interruptContext) {noInterrupts();}
+  if (on ^ invertBrake)
+    setHIGH(fastBrakePin);
+  else
+    setLOW(fastBrakePin);
+  if (!interruptContext) {interrupts();}
+}
+
+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, cheat 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.
+ *
+ * Bool fromISR should be adjusted dependent how function is called
+ */
+int MotorDriver::getCurrentRaw(bool fromISR) {
+  (void)fromISR;
+  if (currentPin==UNUSED_PIN) return 0; 
+  int current;
+  current = ADCee::read(currentPin, fromISR)-senseOffset;
+  if (current<0) current=0-current;
+  if ((faultPin != UNUSED_PIN)  && isLOW(fastFaultPin) && powerMode==POWERMODE::ON)
+      return (current == 0 ? -1 : -current);
+  return current;
+   
+}
+
+#ifdef ANALOG_READ_INTERRUPT
+/*
+ * This should only be called in interrupt context
+ * Copies current value from HW to cached value in
+ * Motordriver.
+ */
+#pragma GCC push_options
+#pragma GCC optimize ("-O3")
+bool MotorDriver::sampleCurrentFromHW() {
+  byte low, high;
+  //if (!bit_is_set(ADCSRA, ADIF))
+  if (bit_is_set(ADCSRA, ADSC))
+    return false;
+  //  if ((ADMUX & mask) != (currentPin - A0))
+  //    return false;
+  low = ADCL; //must read low before high
+  high = ADCH;
+  bitSet(ADCSRA, ADIF);
+  sampleCurrent = (high << 8) | low;
+  sampleCurrentTimestamp = millis();
+  return true;
+}
+void MotorDriver::startCurrentFromHW() {
+#if defined(ARDUINO_AVR_MEGA) || defined(ARDUINO_AVR_MEGA2560)
+  const byte mask = 7;
+#else
+  const byte mask = 31;
+#endif
+  ADMUX=(1<<REFS0)|((currentPin-A0) & mask); //select AVCC as reference and set MUX
+  bitSet(ADCSRA,ADSC); // start conversion
+}
+#pragma GCC pop_options
+#endif //ANALOG_READ_INTERRUPT
+
+#if defined(ARDUINO_ARCH_ESP32)
+uint16_t taurustones[28] = { 165, 175, 196, 220,
+			     247, 262, 294, 330,
+			     249, 392, 440, 494,
+			     523, 587, 659, 698,
+			     494, 440, 392, 249,
+			     330, 284, 262, 247,
+			     220, 196, 175, 165 };
+#endif
+void MotorDriver::setDCSignal(byte speedcode) {
+  if (brakePin == UNUSED_PIN)
+    return;
+#if defined(ARDUINO_AVR_UNO)
+  TCCR2B = (TCCR2B & B11111000) | B00000110; // set divisor on timer 2 to result in (approx) 122.55Hz
+#endif
+#if defined(ARDUINO_AVR_MEGA) || defined(ARDUINO_AVR_MEGA2560)
+  TCCR2B = (TCCR2B & B11111000) | B00000110; // set divisor on timer 2 to result in (approx) 122.55Hz
+  TCCR4B = (TCCR4B & B11111000) | B00000100; // same for timer 4 but maxcount and thus divisor differs
+#endif
+  // spedcoode is a dcc speed & direction
+  byte tSpeed=speedcode & 0x7F; // DCC Speed with 0,1 stop and speed steps 2 to 127
+  byte tDir=speedcode & 0x80;
+  byte brake;
+#if defined(ARDUINO_ARCH_ESP32)
+  {
+    int f = 131;
+    if (tSpeed > 2) {
+      if (tSpeed <= 58) {
+	f = taurustones[ (tSpeed-2)/2 ] ;
+      }
+    }
+    DCCEXanalogWriteFrequency(brakePin, f); // set DC PWM frequency to 100Hz XXX May move to setup
+  }
+#endif
+  if (tSpeed <= 1) brake = 255;
+  else if (tSpeed >= 127) brake = 0;
+  else  brake = 2 * (128-tSpeed);
+  if (invertBrake)
+    brake=255-brake;
+#if defined(ARDUINO_ARCH_ESP32)
+  DCCEXanalogWrite(brakePin,brake);
+#else
+  analogWrite(brakePin,brake);
+#endif
+  //DIAG(F("DCSignal %d"), speedcode);
+  if (HAVE_PORTA(fastSignalPin.shadowinout == &PORTA)) {
+    noInterrupts();
+    HAVE_PORTA(shadowPORTA=PORTA);
+    setSignal(tDir);
+    HAVE_PORTA(PORTA=shadowPORTA);
+    interrupts();
+  } else if (HAVE_PORTB(fastSignalPin.shadowinout == &PORTB)) {
+    noInterrupts();
+    HAVE_PORTB(shadowPORTB=PORTB);
+    setSignal(tDir);
+    HAVE_PORTB(PORTB=shadowPORTB);
+    interrupts();
+  } else if (HAVE_PORTC(fastSignalPin.shadowinout == &PORTC)) {
+    noInterrupts();
+    HAVE_PORTC(shadowPORTC=PORTC);
+    setSignal(tDir);
+    HAVE_PORTC(PORTC=shadowPORTC);
+    interrupts();
+  } else {
+    noInterrupts();
+    setSignal(tDir);
+    interrupts();
+  }
 }
 
 unsigned int MotorDriver::raw2mA( int raw) {
-  return (unsigned int)(raw * senseFactor);
+  //DIAG(F("%d = %d * %d / %d"), (int32_t)raw * senseFactorInternal / senseScale, raw, senseFactorInternal, senseScale);
+  return (int32_t)raw * senseFactorInternal / senseScale;
 }
-int MotorDriver::mA2raw( unsigned int mA) {
-  return (int)(mA / senseFactor);
+unsigned int MotorDriver::mA2raw( unsigned int mA) {
+  //DIAG(F("%d = %d * %d / %d"), (int32_t)mA * senseScale / senseFactorInternal, mA, senseScale, senseFactorInternal);
+  return (int32_t)mA * senseScale / senseFactorInternal;
+}
+
+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.
+#if defined(ARDUINO_ARCH_SAMD)
+    PortGroup *port = digitalPinToPort(pin);
+#elif defined(ARDUINO_ARCH_STM32)
+    GPIO_TypeDef *port = digitalPinToPort(pin);
+#else
+    uint8_t port = digitalPinToPort(pin);
+#endif
+    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);
+}
+
+void MotorDriver::checkPowerOverload(bool useProgLimit, byte trackno) {
+  if (millis() - lastSampleTaken  < sampleDelay) return;
+  lastSampleTaken = millis();
+  int tripValue= useProgLimit?progTripValue:getRawCurrentTripValue();
+  
+  // Trackname for diag messages later
+  switch (powerMode) {
+    case POWERMODE::OFF:
+      sampleDelay = POWER_SAMPLE_OFF_WAIT;
+      break;
+    case POWERMODE::ON:
+      // Check current
+      lastCurrent=getCurrentRaw();
+      if (lastCurrent < 0) {
+	  // We have a fault pin condition to take care of
+	  lastCurrent = -lastCurrent;
+	  setPower(POWERMODE::OVERLOAD); // Turn off, decide later how fast to turn on again
+	  if (commonFaultPin) {
+	      if (lastCurrent < tripValue) {
+		      setPower(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: POWERTOGGLE TRACK %c"), trackno + 'A');
+	  } else {
+	    DIAG(F("TRACK %c FAULT PIN ACTIVE - OVERLOAD"), trackno + 'A');
+	      if (lastCurrent < tripValue) {
+		  lastCurrent = tripValue; // exaggerate
+	      }
+	  }
+      }
+      if (lastCurrent < tripValue) {
+        sampleDelay = POWER_SAMPLE_ON_WAIT;
+	if(power_good_counter<100)
+	  power_good_counter++;
+	else
+	  if (power_sample_overload_wait>POWER_SAMPLE_OVERLOAD_WAIT) power_sample_overload_wait=POWER_SAMPLE_OVERLOAD_WAIT;
+      } else {
+        setPower(POWERMODE::OVERLOAD);
+        unsigned int mA=raw2mA(lastCurrent);
+        unsigned int maxmA=raw2mA(tripValue);
+	      power_good_counter=0;
+        sampleDelay = power_sample_overload_wait;
+        DIAG(F("TRACK %c POWER OVERLOAD %dmA (limit %dmA) shutdown for %dms"), trackno + 'A', mA, maxmA, sampleDelay);
+	if (power_sample_overload_wait >= 10000)
+	    power_sample_overload_wait = 10000;
+	else
+	    power_sample_overload_wait *= 2;
+      }
+      break;
+    case POWERMODE::OVERLOAD:
+      // Try setting it back on after the OVERLOAD_WAIT
+      setPower(POWERMODE::ON);
+      sampleDelay = POWER_SAMPLE_ON_WAIT;
+      // Debug code....
+      DIAG(F("TRACK %c POWER RESTORE (check %dms)"), trackno + 'A', sampleDelay);
+      break;
+    default:
+      sampleDelay = 999; // cant get here..meaningless statement to avoid compiler warning.
+  }
 }

MotorDriver.h

@@ -1,7 +1,12 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2022 Paul M Antoine
+ *  © 2021 Mike S
+ *  © 2021 Fred Decker
+ *  © 2020 Chris Harlow
+ *  © 2022 Harald Barth
+ *  All rights reserved.
  *  
- *  This file is part of Asbelos DCC API
+ *  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
@@ -18,27 +23,215 @@
  */
 #ifndef MotorDriver_h
 #define MotorDriver_h
+#include "FSH.h"
+#include "IODevice.h"
+#include "DCCTimer.h"
+
+#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))
+
+#define TOKENPASTE(x, y) x ## y
+#define TOKENPASTE2(x, y) TOKENPASTE(x, y)
+
+#if defined(ARDUINO_AVR_MEGA) || defined(ARDUINO_AVR_MEGA2560)
+#define HAVE_PORTA(X) X
+#define HAVE_PORTB(X) X
+#define HAVE_PORTC(X) X
+#endif
+#if defined(ARDUINO_AVR_UNO)
+#define HAVE_PORTB(X) X
+#endif
+#if defined(ARDUINO_ARCH_SAMD)
+#define PORTA REG_PORT_OUT0
+#define HAVE_PORTA(X) X
+#define PORTB REG_PORT_OUT1
+#define HAVE_PORTB(X) X
+#endif
+#if defined(ARDUINO_ARCH_STM32)
+#define PORTA GPIOA->ODR
+#define HAVE_PORTA(X) X
+#define PORTB GPIOB->ODR
+#define HAVE_PORTB(X) X
+#define PORTC GPIOC->ODR
+#define HAVE_PORTC(X) X
+#endif
+
+// if macros not defined as pass-through we define
+// them here as someting that is valid as a
+// statement and evaluates to false.
+#ifndef HAVE_PORTA
+#define HAVE_PORTA(X) byte TOKENPASTE2(Unique_, __LINE__) __attribute__((unused)) =0
+#endif
+#ifndef HAVE_PORTB
+#define HAVE_PORTB(X) byte TOKENPASTE2(Unique_, __LINE__) __attribute__((unused)) =0
+#endif
+#ifndef HAVE_PORTC
+#define HAVE_PORTC(X) byte TOKENPASTE2(Unique_, __LINE__) __attribute__((unused)) =0
+#endif
+
 // 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
+
+class pinpair {
+public:
+  pinpair(byte p1, byte p2) {
+    pin = p1;
+    invpin = p2;
+  };
+  byte pin = UNUSED_PIN;
+  byte invpin = UNUSED_PIN;
+};
+
+#if defined(__IMXRT1062__) || defined(ARDUINO_ARCH_ESP8266) || defined(ARDUINO_ARCH_ESP32) || defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_ARCH_STM32)
+typedef uint32_t portreg_t;
+#else
+typedef uint8_t portreg_t;
+#endif
+
+struct FASTPIN {
+  volatile portreg_t *inout;
+  portreg_t maskHIGH;
+  portreg_t maskLOW;
+  volatile portreg_t *shadowinout;
+};
+// The port registers that are shadowing
+// the real port registers. These are
+// defined in Motordriver.cpp
+extern volatile portreg_t shadowPORTA;
+extern volatile portreg_t shadowPORTB;
+extern volatile portreg_t shadowPORTC;
+
+enum class POWERMODE : byte { OFF, ON, OVERLOAD };
+
 class MotorDriver {
   public:
-    MotorDriver(byte power_pin, byte signal_pin, byte signal_pin2, byte brake_pin, byte current_pin, float senseFactor, unsigned int tripMilliamps, byte faultPin);
-    virtual void setPower( bool on);
-    virtual void setSignal( bool high);
-    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;
+    
+    MotorDriver(int16_t power_pin, byte signal_pin, byte signal_pin2, int8_t brake_pin, 
+                byte current_pin, float senseFactor, unsigned int tripMilliamps, byte faultPin);
+    void setPower( POWERMODE mode);
+    POWERMODE getPower() { return powerMode;}
+    // as the port registers can be shadowed to get syncronized DCC signals
+    // we need to take care of that and we have to turn off interrupts if
+    // we setSignal() or setBrake() or setPower() during that time as
+    // otherwise the call from interrupt context can undo whatever we do
+    // from outside interrupt
+    void setBrake( bool on, bool interruptContext=false);
+  __attribute__((always_inline)) inline void setSignal( bool high) {
+      if (trackPWM) {
+	DCCTimer::setPWM(signalPin,high);
+      }
+      else {
+	if (high) {
+	  setHIGH(fastSignalPin);
+	  if (dualSignal) setLOW(fastSignalPin2);
+	}
+	else {
+	  setLOW(fastSignalPin);
+	  if (dualSignal) setHIGH(fastSignalPin2);
+	}
+      }
+    };
+    inline void enableSignal(bool on) {
+      if (on)
+	pinMode(signalPin, OUTPUT);
+      else
+	pinMode(signalPin, INPUT);
+    };
+    inline pinpair getSignalPin() { return pinpair(signalPin,signalPin2); };
+    void setDCSignal(byte speedByte);
+    inline void detachDCSignal() {
+#if defined(__arm__)
+      pinMode(brakePin, OUTPUT);
+#elif defined(ARDUINO_ARCH_ESP32)
+      ledcDetachPin(brakePin);
+#else
+      setDCSignal(128);
+#endif
+    };
+    int  getCurrentRaw(bool fromISR=false);
+    unsigned int raw2mA( int raw);
+    unsigned int mA2raw( unsigned int mA);
+    inline bool brakeCanPWM() {
+#if defined(ARDUINO_ARCH_ESP32) || defined(__arm__)
+      // TODO: on ARM we can use digitalPinHasPWM, and may wish/need to
+      return true;
+#else
+#ifdef digitalPinToTimer
+      return ((brakePin!=UNUSED_PIN) && (digitalPinToTimer(brakePin)));
+#else
+      return (brakePin<14 && brakePin >1);
+#endif //digitalPinToTimer
+#endif //ESP32/ARM
     }
-
+    inline int getRawCurrentTripValue() {
+	    return rawCurrentTripValue;
+    }
+    bool isPWMCapable();
+    bool canMeasureCurrent();
+    bool trackPWM = false; // this track uses PWM timer to generate the DCC waveform
+    static bool commonFaultPin; // This is a stupid motor shield which has only a common fault pin for both outputs
+    inline byte getFaultPin() {
+	return faultPin;
+    }
+    inline void makeProgTrack(bool on) {  // let this output know it's a prog track.
+      isProgTrack = on;
+    }
+    void checkPowerOverload(bool useProgLimit, byte trackno);
+#ifdef ANALOG_READ_INTERRUPT
+    bool sampleCurrentFromHW();
+    void startCurrentFromHW();
+#endif
   private:
-    byte powerPin, signalPin, signalPin2, brakePin,currentPin,faultPin;
-    float senseFactor;
+    bool isProgTrack = false; // tells us if this is a prog track
+    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);
+    }
+    VPIN powerPin;
+    byte signalPin, signalPin2, currentPin, faultPin, brakePin;
+    FASTPIN fastSignalPin, fastSignalPin2, fastBrakePin,fastFaultPin;
+    bool dualSignal;       // true to use signalPin2
+    bool invertBrake;       // brake pin passed as negative means pin is inverted
+    bool invertPower;       // power pin passed as negative means pin is inverted
+    
+    // Raw to milliamp conversion factors avoiding float data types.
+    // Milliamps=rawADCreading * sensefactorInternal / senseScale
+    //
+    // senseScale is chosen as 256 to give enough scale for 2 decimal place 
+    // raw->mA conversion with an ultra fast optimised integer multiplication  
+    int senseFactorInternal;  // set to senseFactor * senseScale
+    static const int senseScale=256;
+    int senseOffset;
     unsigned int tripMilliamps;
     int rawCurrentTripValue;
-    const byte UNUSED_PIN = 255;
+    // current sampling
+    POWERMODE powerMode;
+    unsigned long lastSampleTaken;
+    unsigned int sampleDelay;
+    int progTripValue;
+    int  lastCurrent;
+#ifdef ANALOG_READ_INTERRUPT
+    volatile unsigned long sampleCurrentTimestamp;
+    volatile uint16_t sampleCurrent;
+#endif
+    int maxmA;
+    int tripmA;
+
+    // Wait times for power management. Unit: milliseconds
+    static const int  POWER_SAMPLE_ON_WAIT = 100;
+    static const int  POWER_SAMPLE_OFF_WAIT = 1000;
+    static const int  POWER_SAMPLE_OVERLOAD_WAIT = 20;
     
+    // Trip current for programming track, 250mA. Change only if you really
+    // need to be non-NMRA-compliant because of decoders that are not either.
+    static const int TRIP_CURRENT_PROG=250;
+    unsigned long power_sample_overload_wait = POWER_SAMPLE_OVERLOAD_WAIT;
+    unsigned int power_good_counter = 0;
+
 };
 #endif

MotorDrivers.h

@@ -1,8 +1,30 @@
+/*
+ *  © 2022 Paul M. Antoine
+ *  © 2021 Fred Decker
+ *  © 2020-2022 Harald Barth
+ *  (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.
@@ -13,20 +35,86 @@
 // similar to those defined here, WITHOUT editing this file. You can put your
 // custom defines in config.h.
 
-const byte UNUSED_PIN = 255;
+#ifndef UNUSED_PIN     // sync define with the one in MotorDriver.h
+#define UNUSED_PIN 127 // inside int8_t
+#endif
 
-// MotorDriver(byte power_pin, byte signal_pin, byte signal_pin2, byte brake_pin, byte current_pin,
+// The MotorDriver definition is:
+//
+// MotorDriver(byte power_pin, byte signal_pin, byte signal_pin2, int8_t brake_pin, byte current_pin,
 //             float senseFactor, unsigned int tripMilliamps, byte faultPin);
+//
+// power_pin:     Turns the board on/off. Often called ENABLE or PWM on the shield
+// signal_pin:    Where the DCC signal goes in. Often called DIR on the shield
+// signal_pin2:   Inverse of signal_pin. A few shields need this as well, can be replace by hardware inverter
+// brake_pin:     When tuned on, brake is set - output shortened (*)
+// current_pin:   Current sense voltage pin from shield to ADC
+// senseFactor:   Relation between volts on current_pin and actual output current
+// tripMilliamps: Short circuit trip limit in milliampere, max 32767 (32.767A)
+// faultPin:      Some shields have a pin to to report a fault condition to the uCPU. High when fault occurs
+//
+// (*) If the brake_pin is negative that means the sense
+// of the brake pin on the motor bridge is inverted
+// (HIGH == release brake)
 
-// Arduino standard Motor Shield
+// Arduino STANDARD Motor Shield, used on different architectures:
+
+#if defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_ARCH_STM32)
+// Setup for SAMD21 Sparkfun DEV board using Arduino standard Motor Shield R3 (MUST be R3
+// for 3v3 compatibility!!) senseFactor for 3.3v systems is 1.95 as calculated when using
+// 10-bit A/D samples, and for 12-bit samples it's more like 0.488, but we probably need
+// to tweak both these
 #define STANDARD_MOTOR_SHIELD F("STANDARD_MOTOR_SHIELD"),                                                 \
-                              new MotorDriver(3, 12, UNUSED_PIN, UNUSED_PIN, A0, 2.99, 2000, UNUSED_PIN), \
-                              new MotorDriver(11, 13, UNUSED_PIN, UNUSED_PIN, A1, 2.99, 2000, UNUSED_PIN)
+                              new MotorDriver(3, 12, UNUSED_PIN, 9, A0, 0.488, 1500, UNUSED_PIN), \
+                              new MotorDriver(11, 13, UNUSED_PIN, 8, A1, 0.488, 1500, UNUSED_PIN)
+#define SAMD_STANDARD_MOTOR_SHIELD STANDARD_MOTOR_SHIELD
+#define STM32_STANDARD_MOTOR_SHIELD STANDARD_MOTOR_SHIELD
+
+#elif defined(ARDUINO_ARCH_ESP32)
+// STANDARD shield on an ESPDUINO-32 (ESP32 in Uno form factor). The shield must be eiter the
+// 3.3V compatible R3 version or it has to be modified to not supply more than 3.3V to the
+// analog inputs. Here we use analog inputs A4 and A5 as A0 and A1 are wired in a way so that
+// they are not useable at the same time as WiFi (what a bummer). The numbers below are the
+// actual GPIO numbers. In comments the numbers the pins have on an Uno.
+#define STANDARD_MOTOR_SHIELD F("STANDARD_MOTOR_SHIELD"),                                                 \
+    new MotorDriver(25/* 3*/, 19/*12*/, UNUSED_PIN, 13/*9*/, 36/*A4*/, 0.70, 1500, UNUSED_PIN), \
+    new MotorDriver(23/*11*/, 18/*13*/, UNUSED_PIN, 12/*8*/, 39/*A5*/, 0.70, 1500, UNUSED_PIN)
+
+#else
+// STANDARD shield on any Arduino Uno or Mega compatible with the original specification.
+#define STANDARD_MOTOR_SHIELD F("STANDARD_MOTOR_SHIELD"),                                                 \
+                              new MotorDriver(3, 12, UNUSED_PIN, 9, A0, 2.99, 1500, UNUSED_PIN), \
+                              new MotorDriver(11, 13, UNUSED_PIN, 8, A1, 2.99, 1500, UNUSED_PIN)
+#define BRAKE_PWM_SWAPPED_MOTOR_SHIELD F("BPS_MOTOR_SHIELD"),                                       \
+                              new MotorDriver(-9 , 12, UNUSED_PIN, -3, A0, 2.99, 1500, UNUSED_PIN), \
+                              new MotorDriver(-8 , 13, UNUSED_PIN,-11, A1, 2.99, 1500, UNUSED_PIN)
+#endif
 
 // Pololu Motor Shield
-#define POLOLU_MOTOR_SHIELD F("POLOLU_MOTOR_SHIELD"),                               \
-                            new MotorDriver(4, 7, UNUSED_PIN, 9, A0, 18, 3000, 12), \
-                            new MotorDriver(2, 8, UNUSED_PIN, 10, A1, 18, 3000, UNUSED_PIN)
+#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, 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
+// via the power pins we above use 9 and 10 as power pins and 4 as "inverted brake" which in this
+// 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, 12)
+// See Pololu dial_mc33926_shield_schematic.pdf and truth table on page 17 of the MC33926 data sheet.
+
+// Pololu Dual TB9051FTG Motor Shield
+// This is the shield without modifications. Unfortunately the TB9051FTG driver chip on
+// the shield makes short delays when direction is switched. That means that the chip
+// can NOT provide a standard conformant DCC signal independent how hard we try. If your
+// Decoders tolerate that signal, use it by all mean but it is not recommended. Without
+// modifications it uses the following pins below which means no HA waveform and no
+// RailCom on an Arduino Mega 2560 but the DCC signal is broken anyway.
+#define POLOLU_TB9051FTG F("POLOLU_TB9051FTG"),              \
+   new MotorDriver(2, 7, UNUSED_PIN,  -9, A0, 10, 2500,  6), \
+   new MotorDriver(4, 8, UNUSED_PIN, -10, A1, 10, 2500, 12)
 
 // Firebox Mk1
 #define FIREBOX_MK1 F("FIREBOX_MK1"),                                                  \
@@ -40,7 +128,61 @@ const byte UNUSED_PIN = 255;
 
 // FunduMoto Motor Shield
 #define FUNDUMOTO_SHIELD F("FUNDUMOTO_SHIELD"),                                              \
-                         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)
+                         new MotorDriver(10, 12, UNUSED_PIN, UNUSED_PIN, A0, 2.99, 1500, UNUSED_PIN), \
+                         new MotorDriver(11, 13, UNUSED_PIN, UNUSED_PIN, A1, 2.99, 1500, 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, 1500, 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, 1500, UNUSED_PIN), \
+    new MotorDriver(6, 7, UNUSED_PIN, UNUSED_PIN, A1, 2.99, 1500, UNUSED_PIN)
+
+// Makeblock ORION UNO like sized board with integrated motor driver
+// This is like an Uno with H-bridge and RJ12 contacts instead of pin rows.
+// No current sense. Barrel connector max 12V, Vmotor max 15V. 1.1A polyfuse as output protection.
+// Main is marked M1 and near RJ12 #5
+// Prog is marked M2 and near RJ12 #4
+// For details see
+// http://docs.makeblock.com/diy-platform/en/electronic-modules/main-control-boards/makeblock-orion.html
+#define ORION_UNO_INTEGRATED_SHIELD F("ORION_UNO_INTEGRATED_SHIELD"),		      \
+    new MotorDriver(6, 7, UNUSED_PIN, UNUSED_PIN, UNUSED_PIN, 1.0, 1100, UNUSED_PIN), \
+    new MotorDriver(5, 4, UNUSED_PIN, UNUSED_PIN, UNUSED_PIN, 1.0, 1100, UNUSED_PIN)
+
+// This is an example how to setup a motor shield definition for a motor shield connected
+// to an NANO EVERY board. You have to make the connectons from the shield to the board
+// as in this example or adjust the values yourself.
+#define NANOEVERY_EXAMPLE F("NANOEVERY_EXAMPLE"), \
+ new MotorDriver(5,  6, UNUSED_PIN, UNUSED_PIN, A0, 2.99, 1500, UNUSED_PIN),\
+ new MotorDriver(9, 10, UNUSED_PIN, UNUSED_PIN, A1, 2.99, 1500, UNUSED_PIN)
+
+// This is an example how to stack two standard motor shields. The upper shield
+// needs pins 3 8 9 11 12 13 A0 A1 disconnected from the lower shield and
+// jumpered instead like this:  2-3 6-8 7-9 4-13 5-11 10-12 A0-A4 A1-A5
+// Pin assigment table:
+// 2 Enable C  jumpered
+// 3 Enable A  direct
+// 4 Dir D     jumpered
+// 5 Enable D  jumpered
+// 6 Brake D   jumpered
+// 7 Brake C   jumpered
+// 8 Brake B   direct
+// 9 Brake A   direct
+// 10 Dir C    jumpered
+// 11 Enable B direct
+// 12 Dir A    direct
+// 13 Dir B    direct
+// A0 Sense A  direct
+// A1 Sense B  direct
+// A4 Sense C  jumpered
+// A5 Sense D  jumpered
+//
+#define STACKED_MOTOR_SHIELD F("STACKED_MOTOR_SHIELD"),\
+  new MotorDriver( 3, 12, UNUSED_PIN, 9, A0, 2.99, 1500, UNUSED_PIN), \
+  new MotorDriver(11, 13, UNUSED_PIN, 8, A1, 2.99, 1500, UNUSED_PIN), \
+  new MotorDriver( 2, 10, UNUSED_PIN, 7, A3, 2.99, 1500, UNUSED_PIN), \
+  new MotorDriver( 5,  4, UNUSED_PIN, 6, A4, 2.99, 1500, UNUSED_PIN)
+//
 #endif

Outputs.cpp

@@ -1,5 +1,9 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2021 Neil McKechnie
+ *  © 2021 Harald Barth
+ *  © 2020-2021 Fred Decker
+ *  © 2020-2021 Chris Harlow
+ *  All rights reserved.
  *  
  *  This file is part of Asbelos DCC API
  *
@@ -82,26 +86,50 @@ the state of any outputs being monitored or controlled by a separate interface o
 **********************************************************************/
 
 #include "Outputs.h"
+#ifndef DISABLE_EEPROM
 #include "EEStore.h"
+#endif
+#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);  
+#ifndef DISABLE_EEPROM
+  // Update EEPROM if output has been stored.    
+  if(EEStore::eeStore->data.nOutputs > 0 && num > 0)
+    EEPROM.put(num, data.oStatus);
+#endif
 }
 
 ///////////////////////////////////////////////////////////////////////////////
+// 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 +147,26 @@ bool Output::remove(int n){
   }
 
 ///////////////////////////////////////////////////////////////////////////////
-
+// Static function to load configuration and state of all Outputs from EEPROM
+#ifndef DISABLE_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 +175,26 @@ 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++;
   }
 
 }
-///////////////////////////////////////////////////////////////////////////////
+#endif
 
-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 +207,21 @@ 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

@@ -1,5 +1,8 @@
 /*
- *  © 2020, Chris Harlow. All rights reserved.
+ *  © 2021 Harald Barth
+ *  © 2021 Fred Decker
+ *  © 2020 Chris Harlow
+ *  All rights reserved.
  *  
  *  This file is part of Asbelos DCC API
  *
@@ -20,27 +23,45 @@
 #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);
+#ifndef DISABLE_EEPROM
   static void load();
   static void store();
-  static Output *create(int, int, int, int=0);
+#endif
+  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 many 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.
 
-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, you can read [HERE](https://dcc-ex.com/about/rewrite.html).
 
-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

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/ThrottleAssists.md

@@ -0,0 +1,75 @@
+Throttle Assist updates for versiuon 4.?
+
+Chris Harlow April 2022
+
+There are a number of additional throttle information commands that have been implemented to assist throttle authors to obtain information from the Command Station in order to implement turnout, route/automation and roster features which are already found in the Withrottle implementations. 
+These commands are new and not overlapped with the existing commands which are probabaly due to be obsoleted as they are over complex and unfit for purpose. 
+
+Turnouts:
+
+The conventional turnout definition commands and the ```<H>``` responses do not contain information about the turnout description which may have been provided in an EXRAIL script. A turnout description is much more user friendly than T123 and having a list helps the throttle UI build a suitable set of buttons.
+
+```<JT>``` command returns a list of turnout ids. The throttle should be uninterested in the turnout technology used but needs to know the ids it can throw/close and monitor the current state. 
+e.g.  response ```<jT 1 17 22 19>``` 
+
+```<JT 17>`` requests info on turnout 17.
+e.g. response ```<jT 17 T "Coal yard exit">``` or ```<jT 17 C "Coal yard exit">```
+(T=thrown, C=closed)
+or ```<jT 17 C "">``` indicating turnout description not given. 
+or ```<jT 17 X>``` indicating turnout unknown (or possibly hidden.) 
+
+Note: It is still the throttles responsibility to monitor the status broadcasts.
+ (TBD I'm thinking that the existing broadcast is messy and needs cleaning up)
+ However, I'm not keen on dynamically created/deleted turnouts so I have no intention of providing a command that indicates the turnout list has been updated since the throttle started. 
+ Also note that turnouts marked in EXRAIL with the HIDDEN keyword instead of a "description" will NOT show up in these commands. 
+
+
+ Automations/Routes
+
+ A throttle need to know which EXRAIL Automations and Routes it can show the user.
+
+ ```<JA>``` Returns a list of Automations/Routes
+ e.g. ```<jA 13 16 23>```
+ Indicates route/automation ids.
+ Information on each route needs to be obtained by 
+ ```<JA 13>``` 
+ returns e.g. ```<jA 13 R "description">``` for a route
+ or  ```<jA 13 A "description">``` for an automation. 
+ or ```<jA 13 X>``` for id not found
+
+ Whats the difference: 
+   A Route is just a call to an EXRAIL ROUTE, traditionally to set some turnouts or signals but can be used to perform any kind of EXRAIL function... but its not expecting to know the loco.  
+   Thus a route can be triggered by sending in for example ```</START 13>```. 
+ 
+   An Automation is a handoff of the last accessed loco id to an EXRAIL AUTOMATION which would typically drive the loco away.
+   Thus an Automation expects a start command with a cab id
+   e.g. ```</START 13 3>```
+
+
+   Roster Information:
+   The ```<JR>``` command requests a list of cab ids from the roster.
+   e.g. responding ```<jR 3 200 6336>```
+   or <jR> for none. 
+
+   Each Roster entry had a name and function map obtained by:
+   ```<JR 200>```  reply like ```<jR 200 "Thomas" "whistle/*bell/squeal/panic">
+   
+   Refer to EXRAIL ROSTER command for function map format.
+
+
+  Obtaining throttle status.
+  ```<t cabid>```  Requests a deliberate update on the cab speed/functions in the same format as the cab broadcast.
+     ```<l cabid slot speedbyte functionMap>```
+      Note that a slot of -1 indicates that the cab is not in the reminders table and this comand will not reserve a slot until such time as the cab is throttled.
+
+
+  COMMANDS TO AVOID
+
+  ```<f cab func1 func2>```     Use ```<F cab function 1/0>```
+  ```<t  slot cab speed dir>``` Just drop the slot number 
+  ```<T commands>``` other than ```<T id 0/1>```
+  ```<s>```
+  ```<c>```
+
+
+

Release_Notes/TrackManager.md

@@ -0,0 +1,139 @@
+# DCC++EX Track Manager
+
+Chris Harlow 2022/03/23
+
+**If you are only interested in a standard setup using just a DCC track and PROG track, then you DO NOT need to read the rest of this document.**
+
+What follows is for advanced users interested in managing power districts and/or running DC locomotives through DCC++EX.
+
+## What is the Track Manager
+Track Manger (TM from now on) is an integral part of DCC++EX software that is responsible for:
+- Managing track power state.
+- Monitoring track overloads and shorts.
+- Routing the DCC main or prog track waveforms to the correct Motor Driver and thus track.
+- Managing the JOIN feature.
+- Intercepting throttle commands to locos running on DC tracks.
+- Handling user or EXRAIL commands to switch track status.
+
+In the default scenario of a single DCC track and a PROG track, the TM behaves as for the previous versions of DCC++EX so if thats what you want, you dont need to mess with it.
+
+The TM is able to handle up to 8 separate track domains. Each domain requires a hardware driver to supply track voltage. A typical motor driver shield supplies two tracks, which is what we have used in the past as main and prog.
+
+Unlike the previous version of DCC++EX, where the shield channel A was always the DCC main and channel B was always the DCC prog track, TM allows :
+- None, any or all the tracks can be DCC Main.
+- None or ONE track may be DCC prog at any given time.
+- Any track may be powered on or off independently of the others.
+- Any track may be disconnected from the DCC signal and used as a DC track with a given loco address. (See DC discussion later)
+
+With such flexibility comes responsibility... the potential for making mistakes means taking extra care with your configuration!
+
+**NOTE** TM does NOT use "zero stretching" to control your DC motor. Instead, it uses true Pulse Width Modulation (PWM) to efficiently run your loco using the same method a decoder uses to control a DCC loco's motor. DC locos can even run better on TM than they can on a normal analog throttle, especially at low speed, since it is always applying the full track voltage, albeit in pulses of varying duration. 
+
+## Using the Track Manager (DCC)
+TM names the tracks A to H. In a default setup, you will normally have tracks A and B where A will default to be the DCC main signal and B will be the DCC prog.
+
+There is a new user command `<=>` which is used to control the TM but the `<0>` and `<1>` commands operate as before.
+
+- `<=>`  lists the current track settings.
+In a default setup this will normally return 
+```
+        <=A DCC>
+        <=B PROG>
+```
+- `<=t DCC>`  sets track t (A..H) to use the DCC main track.   For example `<=C DCC>` sets track C. All tracks that are set to DCC will receive the same DCC signal waveform.
+- `<=t PROG>` Sets track t (A..H) to be the one and only PROG track. Any previous PROG track is turned off.
+- `<=t OFF>` turns off the track t. It will not power on with `<1>` because it will not know what signal to send. 
+
+In an all-DCC environment it is unlikely that you will need to do anything other than setting any additional tracks (C...H) as DCC in your `mySetup.h` file.
+
+Bear in mind that a track may actually be only connected to DCC accessories such as signals and turnouts... your layout, your choice. 
+
+Note that when setting a track to PROG or OFF, its power is switched off automatically. (The PROG track manages power on an as-needed basis under normal circumstances.
+When setting a track to MAIN (or DC, DCX see later) the power is applied according to the most recent `<1>` or `<0>` command as being the most compatible with previous versions.
+
+## using the Track Manager (DC)
+
+TM allows any or all of your tracks to be individually selected as a DC track which responds to throttle commands on any given loco address. So for example if track A is set to DC address 55, then any throttle commands to loco 55 will be transmitted as DC onto track A and thus a DC loco can be driven along that track. almost exactly as if it was DCC.
+Your throttle (JMRI, EX-Webthrottle, Withrottle, Engine Driver etc etc) do not know or care that this is a DC loco so nothing needs to change.
+
+For a simple Command Station setup to run just two DC tracks instead of DCC, you only need to assign DC addresses to tracks A and B. If you want DCC on track A and DC on track B, you just need to set track B to a suitable DC address.
+
+The command to set a track to a DC address is as follows 
+- `<=t DC a>` Sets track t (A..H) to use loco address a. e.g. <=A DC 3>
+
+A simple 2 separate loop DC track, wired the traditional way in opposite directions, may be set like this to use loco addresses 1 and 2.  
+```
+<=A DC 1>
+<=A DC 2>
+```
+
+### Crossing between DC tracks 
+
+There are some slightly mind-bending issues to be addressed, especially if you want to be able to cross between two separate DC tracks or use your layout in DCC or DC mode. This is because the control of DC loco direction is relative to the TRACK and not the LOCO. (you turn a DC loco round on the track and it continues in the same geographical direction. You turn a DCC loco around and it continues to go forwards or backwards in the opposite geographical direction.)
+
+Generally DC tracks are wired so that two mainline tracks are in opposite direction which makes operation easy BUT crossovers between tracks will cause shorts unless you have very complex switching arrangements.
+This is generally incompatible with DCC wiring which expects to be able to cross between tracks with impunity because they are all wired with the same polarity. 
+
+To get over this issue TM allows the polarity of a DC track to be swapped so that tracks wired for DCC may be switched to DC with a polarity chosen at run time according to your operations. So, for example, you may have two loops with a crossing between them. Normally you need them in opposite directions, but when you need to drive over the crossing, you need to switch one or other track so that they are at the same polarity.
+(This is a good case for using EXRAIL to help)
+
+The command `<=t DCX a>` will set track t (A..H) to be DC but with reversed polarity compared with a track set to DC.
+
+Its perfectly OK to cross between DC tracks by setting them to the same loco address and making sure you get the polarity right!
+
+## Connecting Hardware
+Each track requires hardware to control it
+- Power on/off
+- Polarity (direction, signal etc)
+- Brake (shorts tracks together)
+- Current (analog reading)
+
+The standard motor shields provide this for two separate tracks and are predictable and easy to use. However STACKING shields is not a viable way of adding more tracks because it prevents the software from gaining access to the individual track pins. Similarly, wiring all the signal pins together for example, will give you a shared DCC signal but it will eliminate any possibility of switching the track purpose at run time. So, you are going to have to understand enough to wire track drivers to various pins if you wish to extend beyond 2 tracks and take advantage of TM.
+
+You will also need to consider the implications of differing electronic implementations that would cause unexpected issues when a loco moves between tracks. We know this works fine for a typical shield because we use `<1 JOIN>` quite happily but this may be different if you mix hardware types..... (NOT MY PROBLEM !) 
+
+The easiest way to consider the wiring is to treat each track individually (either as a separate driver or as half of a shield).
+
+You will require,for each track, on the Arduino:
+- A GPIO pin (or a HAL vpin perhaps on an I2C extender, code TBA!!!) to switch power.
+- A GPIO pin to switch the signal direction
+- A GPIO pin with PWM capability to switch the Brake (you may omit this if you dont want any DC capability)
+- Optionally An Analog pin to read the current (unless your hardware cant do that, perhaps its just feeding a booster)
+- Optionally a GPIO fault pin if thats how your hardware works. (NOT recommended as you're going to run out of pins)
+
+IF you have no more than 3 tracks and you can arrange for the signal pins to be one of 11,12,13 on a Mega, THEN there is a slight advantage internally and the waveform will be super-sharp.
+
+**Hardware that has two signal pins still needs some code thought!!!!!!!!**
+
+
+## Configuring the Software
+
+Configuring the software to provide more tracks is a simple extension of the existing method of customising the #define of MOTOR_SHIELD_TYPE in config.h
+Since there can be no standard setup of your wiring and hardware choices, it will be necessary to create your custom built MOTOR_SHIELD_TYPE in the manner described in MotorDrivers.h and simply continue to add more `new MotorDriver(` definitions to the list, providing all the pin numbers and electronic limits for each track. (or even shorten the list to 1)
+
+## Using EXRAIL to control Track Manager
+EXRAIL has a single additional command that can be used to automate TM.
+
+- `SET_TRACK(t,mode)`
+where t is the track letter A..H and mode is one of
+- `OFF`  track is switched off
+- `DCC`  track gets DCC signal
+- `PROG` track gets DCC prog signal
+- `DC`   track is set to DC mode with the cab address of the currently executing EXRAIL sequence. 
+- `DCX` as DC but with reversed polarity.
+
+DC/DCX are designed so that you can be automating a DCC loco, drive it onto a separate track and switch to DC without having to know the cab address. (e.g AUTOMATION) 
+If however you are just running a ROUTE you can always do something like this:
+```
+ ROUTE(77,"Set track G to DC 123")
+   SETLOCO(123)
+   SET_TRACK(G,DC)
+   DONE
+```
+
+## Where and How for the Code.
+The TM code is primarily in TrackManager.cpp which is responsible for coordinating the track settings and commands. 
+
+Each individual track is handled by an instance of MotorDriver created from the MOTOPR_SHIELD_TYPE definition in config.h 
+
+Many functions formerly in the DCCWaveform code have been moved to TrackManager or MotorDriver, notably the power control and checking. This makes the code easier to follow.