CommandStation-EX/DCCWaveform.h

#include <DIO2.h>
// This hardware configuration would normally be setup in a .h file elsewhere
const byte MAIN_POWER_PIN=3;
const byte MAIN_SIGNAL_PIN=12;
const byte MAIN_SENSE_PIN=A0;

const byte PROG_POWER_PIN=11;
const byte PROG_SIGNAL_PIN=13;
const byte PROG_SENSE_PIN=A1;

const int  POWER_SAMPLE_MAX=300;
const int  POWER_SAMPLE_ON_WAIT=100;
const int  POWER_SAMPLE_OFF_WAIT=1000;
const int  POWER_SAMPLE_OVERLOAD_WAIT=4000;


// ACK current analogRead values (vary depending on motor shield and cpu voltage)
const int   ACK_TIMEOUT = 25 ;  // millis getAck is prepared to wait for a signal
const int   ACK_MAX_NOT_PULSE = 10 ;  // current below which this is NOT a pulse any more
const int   ACK_MIN_PULSE = 50 ;   // current above which a pulse is recognised

const int   PREAMBLE_BITS_MAIN=16;
const int   PREAMBLE_BITS_PROG=22;        

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 idleMessage[]={0xFF,0x00};
const byte resetMessage[]={0x00,0x00};
const byte idlePacket[]={0xFF,0x00,0xFF};
const byte resetPacket[]={0x00,0x00,0x00};

class DCCWaveform {
  public:
   DCCWaveform(byte powerPinNo, byte directionPinNo, byte sensePinNo, byte preambleBits, bool isMain);
   static void begin();
   static void loop();
   static DCCWaveform  mainTrack;
   static DCCWaveform  progTrack; 
   
  void beginTrack();
  void setPowerMode(POWERMODE);
  POWERMODE getPowerMode();
  void checkPowerOverload();
  void schedulePacket(const byte buffer[], byte byteCount, byte repeats);
  volatile bool packetPending;
  bool  startAckProcess();
  bool  getAck();

  
  private:
 
  static void interruptHandler();
  bool interrupt1();
  void interrupt2();
  
  POWERMODE powerMode;

// Transmission controller
  byte transmitPacket[MAX_PACKET_SIZE];  // packet being transmitted
  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];
  byte pendingLength;
  byte pendingRepeats;

  // Hardware pins
  GPIO_pin_t directionPin;
  GPIO_pin_t powerPin;
 
  // current sampling 
  bool isMainTrack;
  byte sensePin;
  unsigned long nextSampleDue;
  int ackBaseCurrent;
  
};