From 3f57c1210d129404b62fdb9bccd9441cf52c5e4b Mon Sep 17 00:00:00 2001
From: Harald Barth <haba@kth.se>
Date: Tue, 17 May 2022 08:06:10 +0200
Subject: [PATCH] turn off signal pin during cutout as that might switch some
 H-bridges between high and low side

---
 DCCTimer.cpp    | 33 ++++++++++++++++++++++++++++++---
 DCCTimer.h      |  1 +
 MotorDriver.cpp |  1 +
 3 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/DCCTimer.cpp b/DCCTimer.cpp
index 97f093d..147f1f0 100644
--- a/DCCTimer.cpp
+++ b/DCCTimer.cpp
@@ -227,6 +227,14 @@ void DCCTimer::read(uint8_t word, uint8_t *mac, uint8_t offset) {
       TCNT4 = 0;  // this timer fires half cycle after Timer 1 (no idea why /4 !)     
       #endif
     
+      // turn on PWM for the pins here (instead of in setPWM())
+      // only needed if RailCom is inactive as otherwise RailCom
+      // takes care of that. Does not hurt tough
+      onoffPWM(TIMER1_A_PIN, true);
+      onoffPWM(TIMER1_B_PIN, true);
+#ifdef TIMER1_C_PIN
+      onoffPWM(TIMER1_C_PIN, true);
+#endif
     interrupts();
   }
 
@@ -253,19 +261,38 @@ void DCCTimer::read(uint8_t word, uint8_t *mac, uint8_t offset) {
               false;
   }
 
+void DCCTimer::onoffPWM(byte pin, bool on) {
+  if (pin==TIMER1_A_PIN) {
+    if (on)
+      TCCR1A |= _BV(COM1A1);
+    else
+      TCCR1A &= ~(_BV(COM1A1));
+  }
+  else if (pin==TIMER1_B_PIN) {
+    if (on)
+      TCCR1A |= _BV(COM1B1);
+    else
+      TCCR1A &= ~(_BV(COM1B1));
+  }
+#ifdef TIMER1_C_PIN
+  else if (pin==TIMER1_C_PIN) {
+    if (on)
+      TCCR1A |= _BV(COM1C1);
+    else
+      TCCR1A &= ~(_BV(COM1C1));
+  }
+#endif
+}
  void DCCTimer::setPWM(byte pin, bool high) {
     uint16_t val=high?1024:0;
     if (pin==TIMER1_A_PIN) {
-      TCCR1A |= _BV(COM1A1);
       OCR1A= val;
     }
     else if (pin==TIMER1_B_PIN) { 
-      TCCR1A |= _BV(COM1B1);
       OCR1B= val;
     }
  #ifdef TIMER1_C_PIN 
     else if (pin==TIMER1_C_PIN) { 
-      TCCR1A |= _BV(COM1C1);
       OCR1C= val;
     }
  #endif       
diff --git a/DCCTimer.h b/DCCTimer.h
index 0452bb7..beda7fd 100644
--- a/DCCTimer.h
+++ b/DCCTimer.h
@@ -11,6 +11,7 @@ class DCCTimer {
   static bool isPWMPin(byte pin);
   static bool isRailcomPin(byte pin);
   static void setPWM(byte pin, bool high);
+  static void onoffPWM(byte pin, bool on);
 #if (defined(TEENSYDUINO) && !defined(__IMXRT1062__))
   static void read_mac(byte mac[6]);
   static void read(uint8_t word, uint8_t *mac, uint8_t offset);
diff --git a/MotorDriver.cpp b/MotorDriver.cpp
index babd102..86574ae 100644
--- a/MotorDriver.cpp
+++ b/MotorDriver.cpp
@@ -115,6 +115,7 @@ void MotorDriver::setBrake(bool on) {
 }
 
 void MotorDriver::setRailcomCutout(bool on) {
+  DCCTimer::onoffPWM(signalPin,!on);
   DCCTimer::setPWM(brakePin,on ^ invertBrake);
 }