//------------------------------------------------------------------------------
// tms470r1a256_CAN_03.c - CAN Monitor Demo
//
// Description: This demo code serves as a simple CAN bus monitor. It uses the
// standard CAN controller (SCC) to receive any incoming CAN messages (with
// both 11-bit and 29-bit identifiers) using interrupts. These messages are
// decoded and output as text to the SCI1 module for display in a terminal
// program such as HyperTerm.
//
//            TMS470R1A256
//      /|\ +---------------+
//       |  |               |
//       +--|PLLDIS    GIOA2|<--- Button#1
//          |               |
//          |           HET0|---> LED
//          |               |
//          |       XIN/XOUT|<--- 12MHz crystal
//          |               |
//          |         CANSTX|---> CAN network, 125kbit/s
//          |         CANSRX|<---
//          |          GIOB1|---> CAN transceiver enable
//          |               |
//          +---------------+
//
// Andreas Dannenberg / John Mangino
// Texas Instruments Inc.
// April 12th 2005
// Built with IAR Embedded Workbench Version: 4.11A
//------------------------------------------------------------------------------

#include "stdio.h"
#include "yfuns.h"                              // Customize standard I/O
#include "intrinsic.h"                          // ARM7 specific intrinsics
#include "iotms470r1a256.h"                     // TMS470 register definitions
#include "tms470r1a256_bit_definitions.h"

void SCI_Init(void);
void CAN_Init(void);
void SCCB_irq_handler(void);

void main(void)
{
  PCR = CLKDIV_1;                               // ICLK = SYSCLK = 12MHz
  PCR |= PENABLE;                               // Enable peripherals

  HETDIR = 0x813c3dd5;                          // Set HET as GIO outputs
  HETDOUT = 0x813c3dd5;                         // All LEDs off

  GIODIRB = X1;                                 // Set GIOB1 to output
  GIODCLRB = X1;                                // Output 0 on GIOB1 to enable
                                                // external CAN transceiver

  SCI_Init();                                   // Init SCI module
  CAN_Init();                                   // Init standard CAN controller

  REQMASK = (1 << CIM_SCCB);                    // Enable SCCB int mask

  printf("\r\n\r\n    *** TMS470 CAN Monitor Demo ***");
  printf("\r\n   ID    RTR DLC D0 D1 D2 D3 D4 D5 D6 D7");

  __enable_interrupt();                         // Enable interrupts

  while (1)                                     // Loop forever...
  {
  }
}
//------------------------------------------------------------------------------
// SCI1 Initialization
//
// Configures the SCI1 UART module for transmit operation using a data
// rate of 115,200bps.
//------------------------------------------------------------------------------
void SCI_Init(void)
{
  SCI1CTL3 &= ~SW_NRESET;                       // Reset SCI1 state machine
  SCI1CCR = TIMING_MODE_ASYNC + CHAR_8;         // Async, 8-bit Char
  SCI1CTL2 |= TXENA;                            // TX enabled
  SCI1CTL3 |= CLOCK;                            // Internal clock
  SCI1LBAUD = 12;                               // 12MHz/8/115,200-1=12
  SCI1PC3 |= TX_FUNC;                           // SCITX is the SCI transmit pin
  SCI1CTL3 |= SW_NRESET;                        // Configure SCI1 state machine
}
//------------------------------------------------------------------------------
// Standard CAN Controller Initialization
//
// Sets up the CAN controller for operation at 125kbit/s. Two mailboxes are
// initialized for receiving (mailbox 0) and transmitting (mailbox 1) messages
// with a standard 11-bit ID of 0x400. Interrupts are enabled to indicate
// incoming messages.
//------------------------------------------------------------------------------
void CAN_Init(void)
{
  // Use CANTX pin for the CAN transmit functions
  CAN1TIOC = TXFUNC;

  // Use CANRX pin for the CAN receive functions
  CAN1RIOC = RXFUNC;

  // Set SCC interrupt configuration. Mailbox 0 (receive mailbox) generates
  // low-priority interrupts (int line 1 --> CIM_SCCB).
  CAN1MIL = MIL0;                               // Use int line 1 for mbox 0
  CAN1MIM = MIM0;                               // Enable int for mbox 0
  CAN1GIM = I1EN;                               // Enable int line 1

  // Setup master control register
  // Enable configuration mode, activate auto bus on after bus off condition
  CAN1MC = CCR + ABO;

  // Wait until CPU has access to CAN configuration registers
  while (!(CAN1ES & CCE));

  // Setup CAN bit timing for 125kbit/s according to CiA specifications:
  // 8us nominal bit time w/ 16TQs/bit, sample point is located at 7us (14TQ)
  // BRP = 5 (Prescaler 6, w/ ICLK = 12MHz)
  // Sample 3x, TSEG1 = 13, TSEG2 = 2, SJW = 1
  CAN1BTC = (5 << 16) + SAM + TSEG1_13 + TSEG2_2 + SJW_1;

  // Setup local acceptance mask LAM0
  // Receive any incoming standard/extended ID message
  CAN1LAM0 = LAMI + 0x1fffffff;

  // Configure mailbox 0 for receive
  CAN1MID0 = AME;                               // Use acceptance mask LAM0
  CAN1MCF0 = 0x00;
  CAN1MDL0 = 0x00;
  CAN1MDH0 = 0x00;

  CAN1MD = MD0;                                 // Use mbox 0 for RX
  CAN1OPC = OPC0;                               // Protect against overwrite
  CAN1ME = ME0;                                 // Enable mailbox 0

  // Start CAN module
  CAN1MC &= ~CCR;

  // Wait until CAN module is started
  while (CAN1ES & CCE);
}
//------------------------------------------------------------------------------
// SCI1 UART based character output function to be used by __write().
//------------------------------------------------------------------------------
int MyLowLevelPutchar(int x)
{
  while (!(SCI1CTL2 & TXRDY));                  // TX buffer ready?
  SCI1TXBUF = x;                                // Transmit character
  return x;                                     // Indicate "no error"
}
//------------------------------------------------------------------------------
// Provide custom low-level __write() function to be used for console I/O.
// This function is based on the IAR template file <...>\arm\src\lib\write.c
//------------------------------------------------------------------------------
size_t __write(int handle, const unsigned char * buffer, size_t size)
{
  size_t nChars = 0;

  if (buffer == 0)
  {
    /*
     * This means that we should flush internal buffers.  Since we
     * don't we just return.  (Remember, "handle" == -1 means that all
     * handles should be flushed.)
     */
    return 0;
  }

  /* This template only writes to "standard out" and "standard err",
   * for all other file handles it returns failure.
   */
  if (handle != _LLIO_STDOUT && handle != _LLIO_STDERR)
  {
    return _LLIO_ERROR;
  }

  for (/* Empty */; size != 0; --size)
  {
    if (MyLowLevelPutchar(*buffer++) < 0)
    {
      return _LLIO_ERROR;
    }

    ++nChars;
  }

  return nChars;
}
//------------------------------------------------------------------------------
// SCCB Interrupt Handler
//
// Checks if a new CAN message was received into mailbox 0, and adjusts the
// LED status variable and the actual LED according to the message contents.
//------------------------------------------------------------------------------
void SCCB_irq_handler(void)
{
  if (CAN1GIF1 & GMIF1)                         // Msg received?
    if ((CAN1GIF1 & 0xf) == MIV1_0)             // Mailbox 0?
    {
      if (CAN1MID0 & IDE)                       // Extended identifier?
        printf("\r\n%08x", CAN1MID0 & 0x1fffffff);  // Print ext. ID
      else
        printf("\r\n     %03x", (CAN1MID0 >> 18) & 0x7ff);  // Print std. ID

      if (CAN1MCF0 & RTR)                       // Remote TX request?
        printf(" RTR");                         // Yes
      else
        printf("    ");                         // No

      unsigned int DLC_Temp = CAN1MCF0 & 0x7;   // Get DLC field

      printf(" %02x", DLC_Temp);                // Print DLC

      if (DLC_Temp--) { printf("  %02x", CAN1MDL0 >> 24);
        if (DLC_Temp--) { printf(" %02x", (CAN1MDL0 >> 16) & 0xff);
          if (DLC_Temp--) { printf(" %02x", (CAN1MDL0 >>  8) & 0xff);
            if (DLC_Temp--) { printf(" %02x",  CAN1MDL0        & 0xff);
              if (DLC_Temp--) { printf(" %02x",  CAN1MDH0 >> 24);
                if (DLC_Temp--) { printf(" %02x", (CAN1MDH0 >> 16) & 0xff);
                  if (DLC_Temp--) { printf(" %02x", (CAN1MDH0 >>  8) & 0xff);
                    if (DLC_Temp)     printf(" %02x",  CAN1MDH0        & 0xff);
      }}}}}}}

      CAN1RMP = RMP0;                           // Clear flag, new msg can be
    }                                           // received now
}
//------------------------------------------------------------------------------
// TMS470R1A256 Standard Interrupt Handler
//------------------------------------------------------------------------------
#pragma vector = IRQV
__irq __arm void irq_handler(void)
{
  switch ((IRQIVEC & 0xff) - 1)                 // Convert IVEC index to
  {                                             // CIM interrupt channel
    case CIM_SCCB :                             // SCC interrupt B
      SCCB_irq_handler();
      break;
  }
}