Expand signed pin type to 16 bit so we can return 255/-255 (UNUSED_PIN)

Author: habazut

DCCTimer.h

@@ -67,7 +67,7 @@ class DCCTimer {
   static void DCCEXanalogWriteFrequency(uint8_t pin, uint32_t frequency);
   static void DCCEXanalogWrite(uint8_t pin, int value, bool invert);
   static void DCCEXledcDetachPin(uint8_t pin);
-  static void DCCEXanalogCopyChannel(int8_t frompin, int8_t topin);
+  static void DCCEXanalogCopyChannel(int16_t frompin, int16_t topin);
   static void DCCEXInrushControlOn(uint8_t pin, int duty, bool invert);
   static void DCCEXledcAttachPin(uint8_t pin, int8_t channel, bool inverted);
 

DCCTimerESP.cpp

@@ -22,6 +22,10 @@
 // Please refer to DCCTimer.h for general comments about how this class works
 // This is to avoid repetition and duplication.
 
+#ifndef UNUSED_PIN     // sync define with the one in MotorDrivers.h and MotorDriver.h
+#define UNUSED_PIN 255 // inside uint8_t
+#endif
+
 #ifdef ARDUINO_ARCH_ESP8266
 
 #include "DCCTimer.h"
@@ -236,16 +240,24 @@ void DCCTimer::DCCEXledcAttachPin(uint8_t pin, int8_t channel, bool inverted) {
     gpio_matrix_out(pin, LEDCToMux[channel], inverted, 0);
 }
 
-void DCCTimer::DCCEXanalogCopyChannel(int8_t frompin, int8_t topin) {
+void DCCTimer::DCCEXanalogCopyChannel(int16_t frompin, int16_t topin) {
   // arguments are signed depending on inversion of pins
-  DIAG(F("Pin %d copied to %d"), frompin, topin);
+  //DIAG(F("Pin %d copied to %d"), frompin, topin);
   bool inverted = false;
   if (frompin<0)
     frompin = -frompin;
   if (topin<0) {
     inverted = true;
     topin = -topin;
   }
+  if (frompin == UNUSED_PIN) {
+    DIAG(F("Can not copy from unused frompin"));
+    return;
+  }
+  if (topin == UNUSED_PIN) {
+    DIAG(F("Can not copy to unused topin"));
+    return;
+  }
   int channel = pin_to_channel[frompin]; // after abs(frompin)
   pin_to_channel[topin] = channel;
   DCCTimer::DCCEXledcAttachPin(topin, channel, inverted);

MotorDriver.h

@@ -219,7 +219,7 @@ class MotorDriver {
       }
     };
     inline pinpair getSignalPin() { return pinpair(signalPin,signalPin2); };
-    inline int8_t getBrakePinSigned() { return invertBrake ? -brakePin : brakePin; };
+    inline int16_t getBrakePinSigned() { return invertBrake ? -brakePin : brakePin; };
     void setDCSignal(byte speedByte, uint8_t frequency=0);
     void throttleInrush(bool on);
     inline void detachDCSignal() {