tms470r1a256_sci2_02.c

tmp470开发板的源程序

//*******************************************************************************
//  TMS470 Demo - SCI2 19200 Transmit String
//
//  Description; Transmit the string "Hello World" using SCI2. The RTI tap
//  interrupt enables the SCI2 TX interrupt allowing transmission of string.
//  At completion of string transmission, the SCI2 ISR disables further
//  transmission.
//  RTI tap divides ICLK/2^20
//  ACLK = ICLK = SYSCLK = MCLK = 12MHz
//  Baud rate divider with 12MHz ICLKL @19200 = 12MHz/(8*19200)-1 = 0x4D
//
//  //*An external 12Mhz XTAL on OSCIN OSCOUT with proper load caps required*//	
//
//              TMS-FET470A256
//             -----------------
//         /|\|            OSCIN|-
//          | |                 | 12MHz
//          --|PLLDIS     OSCOUT|-
//            |                 |
//            |           SCI2TX|------------>
//            |                 | 19200 - 8N1
//            |           SCI2RX|<------------
//
//  M.Buccini/A.Dannenberg
//  Texas Instruments, Inc
//  January 2005
//  Built with IAR Embedded Workbench Version: 4.20A
//******************************************************************************

#include <intrinsic.h>
#include "iotms470r1a256.h"
#include "tms470r1a256_bit_definitions.h"

const char string1[] = { "Hello World\r\n" };
unsigned int i = 0;

void main(void)
{
  PCR = CLKDIV_1;                         // ICLK = SYSCLK
  PCR |= PENABLE;                         // enable peripherals

  SCI2CTL3 &= ~SW_NRESET;                 // Reset SCI state machine
  SCI2CCR = TIMING_MODE_ASYNC + CHAR_8;   // Async, 8-bit Char
  SCI2CTL1 |= RXENA;                      // RX enabled
  SCI2CTL2 |= TXENA;                      // TX enabled
  SCI2CTL3 |= CLOCK;                      // Internal clock
  SCI2LBAUD = 0x4d;                       // 12MHz/(8*19200)-1
  SCI2PC2 |= RX_FUNC;                     // SCIRX is the SCI receive pin
  SCI2PC3 |= TX_FUNC;                     // SCITX is the SCI transmit pin
  SCI2CTL3 |= SW_NRESET;                  // Configure SCI2 state machine
  RTIPCTL = 1;                            // Preload modulo /1
  RTICNTL |= TAPENA;                      // Enable TAP interrupt
  REQMASK = (1 << CIM_SCI2TX)+(1 << CIM_TAP); // Enable SCI2TX, RTI tap chan's
  __enable_interrupt();                   // Enable interrupts

  for (;;) {}
}
//------------------------------------------------------------------------------
// TMS470R1A256 Standard Interrupt Handler
//------------------------------------------------------------------------------
#pragma vector = IRQV
__irq __arm void irq_handler(void)
{
  switch ((0xff & IRQIVEC) - 1)
  {
    case CIM_TAP:
    {
      i = 0;
      SCI2TXBUF = string1[i++];           // First char to TX buffer
      SCI2CTL3 |= TX_ACTION_ENA;          // Enable TX interrupt
      RTICNTL &= ~TAPFLAG;                // Clear TAP flag
      break;
    }
    case CIM_SCI2TX:
    {
      if (i < sizeof string1-1)
        SCI2TXBUF = string1[i++];
      else
        SCI2CTL3 &= ~ TX_ACTION_ENA;      // Disable TX interrupt
      break;
    }
  }
}