From 7e58165db9aa35e1ca60e6c7e053099c97935674 Mon Sep 17 00:00:00 2001
From: Asbelos <asbelos@btinternet.com>
Date: Tue, 11 May 2021 16:33:12 +0100
Subject: [PATCH] First working

---
 DCCTimer.cpp    | 25 +++++++++++--------------
 DCCWaveform.cpp |  6 +++---
 2 files changed, 14 insertions(+), 17 deletions(-)

diff --git a/DCCTimer.cpp b/DCCTimer.cpp
index 7ffa3a5..1a01a30 100644
--- a/DCCTimer.cpp
+++ b/DCCTimer.cpp
@@ -164,7 +164,7 @@ void DCCTimer::read(uint8_t word, uint8_t *mac, uint8_t offset) {
     #define TIMER1_B_PIN   12
     #define TIMER1_C_PIN   13
     //railcom timer facility
-  //  #define TIMER4_A_PIN   6
+    #define TIMER4_A_PIN   6
     #define TIMER4_B_PIN   7
     #define TIMER4_C_PIN   8
  #else
@@ -178,19 +178,20 @@ void DCCTimer::read(uint8_t word, uint8_t *mac, uint8_t offset) {
     ADCSRA = (ADCSRA & 0b11111000) | 0b00000100;   // speed up analogRead sample time 
     TCCR1A = 0;
     ICR1 = CLOCK_CYCLES;
-    TCNT1 = 0;   
     TCCR1B = _BV(WGM13) | _BV(CS10);     // Mode 8, clock select 1
     TIMSK1 = _BV(TOIE1); // Enable Software interrupt
+    TCNT1 = 0;   
     
     #if defined(TIMER4_A_PIN)
       //railcom timer facility
       TCCR4A = 0;
       ICR4 = CLOCK_CYCLES;
-      TCNT4 = CLOCK_CYCLES/2;  // this timer fires half cycle after Timer 1     
-      TCCR4B = _BV(WGM13) | _BV(CS10);     // Mode 8, clock select 1
+      TCCR4B = _BV(WGM43) | _BV(CS40);     // Mode 8, clock select 1
       TIMSK4 = 0; // Disable Software interrupt
+      delayMicroseconds(DCC_SIGNAL_TIME/2);  
+      TCNT4 = 0;  // this timer fires half cycle after Timer 1 (no idea why /4 !)     
       #endif
-
+    
     interrupts();
   }
 
@@ -208,7 +209,7 @@ void DCCTimer::read(uint8_t word, uint8_t *mac, uint8_t offset) {
   }
 // Alternative pin manipulation via PWM control.
   bool DCCTimer::isRailcomPin(byte pin) {
-       return 
+       return  
        #ifdef TIMER4_A_PIN 
               pin==TIMER4_A_PIN ||
               pin==TIMER4_B_PIN ||
@@ -218,7 +219,7 @@ void DCCTimer::read(uint8_t word, uint8_t *mac, uint8_t offset) {
   }
 
  void DCCTimer::setPWM(byte pin, bool high) {
-    byte val=high?1024:0;
+    uint16_t val=high?1024:0;
     if (pin==TIMER1_A_PIN) {
       TCCR1A |= _BV(COM1A1);
       OCR1A= val;
@@ -235,19 +236,15 @@ void DCCTimer::read(uint8_t word, uint8_t *mac, uint8_t offset) {
  #endif       
  #ifdef TIMER4_A_PIN 
     else if (pin==TIMER4_A_PIN) { 
-      TCCR4A |= _BV(COM4A1); //??????????????????????????????????
+      TCCR4A |= _BV(COM4A1); 
       OCR4A= val;
     }
- #endif       
- #ifdef TIMER4_B_PIN 
     else if (pin==TIMER4_B_PIN) { 
-      TCCR4B |= _BV(COM4B1); //??????????????????????????????????
+      TCCR4A |= _BV(COM4B1); 
       OCR4B= val;
     }
- #endif       
- #ifdef TIMER4_C_PIN 
     else if (pin==TIMER4_C_PIN) { 
-      TCCR4C |= _BV(COM4C1); //??????????????????????????????????
+      TCCR4A |= _BV(COM4C1); 
       OCR4C= val;
     }
  #endif       
diff --git a/DCCWaveform.cpp b/DCCWaveform.cpp
index e75060e..2ab014f 100644
--- a/DCCWaveform.cpp
+++ b/DCCWaveform.cpp
@@ -210,12 +210,12 @@ void DCCWaveform::interrupt2() {
     state=WAVE_MID_1;  // switch state to trigger LOW on next interrupt
     remainingPreambles--;
     // Railcom cutout
-    if (remainingPreambles==requiredPreambles-2) motorDriver->setRailcomCutout(true);
-    else if (remainingPreambles==requiredPreambles-4) motorDriver->setRailcomCutout(false);
+    if (remainingPreambles==(requiredPreambles-2)) motorDriver->setRailcomCutout(true);
+    else if (remainingPreambles==(requiredPreambles-4)) motorDriver->setRailcomCutout(false);
      
     // 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.
-    updateMinimumFreeMemory(22); 
+    else updateMinimumFreeMemory(22); 
     return;
   }