/******************************************************************************
* Function: initCAN
* Description: Initialises the ECAN module
* Arguments: none
******************************************************************************/
void initECAN (void)
{
  unsigned long temp;
  unsigned int tempint;
  /* put the module in configuration mode */
  C1CTRL1bits.REQOP=4;
  while(C1CTRL1bits.OPMODE != 4);
  /* FCAN is selected to be FCY
    FCAN = FCY = 40MHz */
    C1CTRL1bits.CANCKS = 0x1;
  /*
  Bit Time = (Sync Segment + Propagation Delay + Phase Segment 1 + Phase Segment 2)=20*TQ
  Phase Segment 1 = 8TQ
  Phase Segment 2 = 6Tq
  Propagation Delay = 5Tq
  Sync Segment = 1TQ
  CiCFG1<BRP> =(FCAN /(2 ×N×FBAUD))– 1
  BIT RATE OF 1Mbps
  */
  C1CFG1bits.BRP = BRP_VAL;
  /* Synchronization Jump Width set to 4 TQ */
  C1CFG1bits.SJW = 0x3;
  /* Phase Segment 1 time is 8 TQ */
  C1CFG2bits.SEG1PH=0x7;
  /* Phase Segment 2 time is set to be programmable */
  C1CFG2bits.SEG2PHTS = 0x1;
  /* Phase Segment 2 time is 6 TQ */
  C1CFG2bits.SEG2PH = 0x5;
  /* Propagation Segment time is 5 TQ */
  C1CFG2bits.PRSEG = 0x4;
  /* Bus line is sampled three times at the sample point */
  C1CFG2bits.SAM = 0x1;
  /* 4 CAN Messages to be buffered in DMA RAM */
  C1FCTRLbits.DMABS=0b000;
  /* Filter configuration */
  /* enable window to access the filter configuration registers */
  C1CTRL1bits.WIN=0b1;
  /* select acceptance mask 0 filter 0 buffer 1 */
  C1FMSKSEL1bits.F0MSK=0;
  /* configure accpetence mask 0 - match the id in filter 0
  setup the mask to check every bit of the standard message,
  the macro when called as CAN_FILTERMASK2REG_SID(0x7FF) will
  write the register C1RXM0SID to include every bit in filter comparison
  */
  C1RXM0SID=CAN_FILTERMASK2REG_SID(0x7FF);
  /* configure accpetence filter 0
  setup the filter to accept a standard id of 0x123,
  the macro when called as CAN_FILTERMASK2REG_SID(0x123) will
  write the register C1RXF0SID to accept only standard id of 0x123
  */
  C1RXF0SID=CAN_FILTERMASK2REG_SID(0x123);
  /* set filter to check for standard ID and accept standard id only */
  C1RXM0SID=CAN_SETMIDE(C1RXM0SID);
  C1RXF0SID=CAN_FILTERSTD(C1RXF0SID);
  /* acceptance filter to use buffer 1 for incoming messages */
  C1BUFPNT1bits.F0BP=0b0001;
  /* enable filter 0 */
  C1FEN1bits.FLTEN0=1;
  /* select acceptance mask 1 filter 1 and buffer 2 */
  C1FMSKSEL1bits.F1MSK=0b01;
  /* configure accpetence mask 1 - match id in filter 1
  setup the mask to check every bit of the extended message,
  the macro when called as CAN_FILTERMASK2REG_EID0(0xFFFF)
  will write the register C1RXM1EID to include extended
  message id bits EID0 to EID15 in filter comparison.
  the macro when called as CAN_FILTERMASK2REG_EID1(0x1FFF)
  will write the register C1RXM1SID to include extended
  message id bits EID16 to EID28 in filter comparison.
  */
  C1RXM1EID=CAN_FILTERMASK2REG_EID0(0xFFFF);
  C1RXM1SID=CAN_FILTERMASK2REG_EID1(0x1FFF);
  /* configure acceptance filter 1
  configure accpetence filter 1 - accept only XTD ID 0x12345678
  setup the filter to accept only extended message 0x12345678,
  the macro when called as CAN_FILTERMASK2REG_EID0(0x5678)
  will write the register C1RXF1EID to include extended
  message id bits EID0 to EID15 when doing filter comparison.
  the macro when called as CAN_FILTERMASK2REG_EID1(0x1234)
  will write the register C1RXF1SID to include extended
  message id bits EID16 to EID28 when doing filter comparison.
  */
  C1RXF1EID=CAN_FILTERMASK2REG_EID0(0x5678);
  C1RXF1SID=CAN_FILTERMASK2REG_EID1(0x1234);
  /* filter to check for extended ID only */
  C1RXM1SID=CAN_SETMIDE(C1RXM1SID);
  C1RXF1SID=CAN_FILTERXTD(C1RXF1SID);
  /* acceptance filter to use buffer 2 for incoming messages */
  C1BUFPNT1bits.F1BP=0b0010;
  /* enable filter 1 */
  C1FEN1bits.FLTEN1=1;
  /* select acceptance mask 1 filter 2 and buffer 3 */
  C1FMSKSEL1bits.F2MSK=0b01;
  /* configure acceptance filter 2
  configure accpetence filter 2 - accept only XTD ID 0x12345679
  setup the filter to accept only extended message 0x12345679,
  the macro when called as CAN_FILTERMASK2REG_EID0(0x5679)
  will write the register C1RXF1EID to include extended
  message id bits EID0 to EID15 when doing filter comparison.
  the macro when called as CAN_FILTERMASK2REG_EID1(0x1234)
  will write the register C1RXF1SID to include extended
  message id bits EID16 to EID28 when doing filter comparison.
  */
  C1RXF2EID=CAN_FILTERMASK2REG_EID0(0x5679);
  C1RXF2SID=CAN_FILTERMASK2REG_EID1(0x1234);
  /* filter to check for extended ID only */
  C1RXF2SID=CAN_FILTERXTD(C1RXF2SID);
  /* acceptance filter to use buffer 3 for incoming messages */
  C1BUFPNT1bits.F2BP=0b0011;
  /* enable filter 2 */
  C1FEN1bits.FLTEN2=1;

  /* clear window bit to access ECAN control registers */
  C1CTRL1bits.WIN=0;
  /* put the module in normal mode */
  C1CTRL1bits.REQOP=0;
  while(C1CTRL1bits.OPMODE != 0);
  /* clear the buffer and overflow flags */
  C1RXFUL1=C1RXFUL2=C1RXOVF1=C1RXOVF2=0x0000;
  /* ECAN1, Buffer 0 is a Transmit Buffer */
  C1TR01CONbits.TXEN0=1;
  /* ECAN1, Buffer 1 is a Receive Buffer */
  C1TR01CONbits.TXEN1=0;
  /* ECAN1, Buffer 2 is a Receive Buffer */
  C1TR23CONbits.TXEN2=0;
  /* ECAN1, Buffer 3 is a Receive Buffer */
  C1TR23CONbits.TXEN3=0;
  /* Message Buffer 0 Priority Level */
  C1TR01CONbits.TX0PRI=0b11;
  /* configure the device to interrupt on the receive buffer full flag */
  /* clear the buffer full flags */
  C1RXFUL1=0;
  C1INTFbits.RBIF=0;
}