msp430x54x_ta3_03.c

msp430单片机最新的产品MSP430F5438内部定时计数器的操作的示例程序

//******************************************************************************
//  MSP430F54x Demo - Timer_A3, Toggle P1.0, Overflow ISR, DCO SMCLK
//
//  Description: Toggle P1.0 using software and Timer1_A overflow ISR.
//  In this example an ISR triggers when TA overflows. Inside the TA
//  overflow ISR P1.0 is toggled. Toggle rate is approximatlely 16.8Hz.
//  Proper use of the TAIV interrupt vector generator is demonstrated.
//  ACLK = n/a, MCLK = SMCLK = TACLK = default DCO ~1.05MHz
//
//           MSP430F5438
//         ---------------
//     /|\|               |
//      | |               |
//      --|RST            |
//        |               |
//        |           P1.0|-->LED
//
//   M Smertneck / W. Goh
//   Texas Instruments Inc.
//   September 2008
//   Built with CCE Version: 3.2.2 and IAR Embedded Workbench Version: 4.11B
//******************************************************************************

#include "msp430x54x.h"

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  P1DIR |= 0x01;                            // P1.0 output
  TA1CTL = TASSEL_2 + MC_2 + TACLR + TAIE;  // SMCLK, contmode, clear TAR
                                            // enable interrupt

  __bis_SR_register(LPM0_bits + GIE);       // Enter LPM0, enable interrupts
  __no_operation();                         // For debugger
}

// Timer_A3 Interrupt Vector (TAIV) handler
#pragma vector=TIMER1_A1_VECTOR
__interrupt void TIMER1_A1_ISR(void)
{
  switch(__even_in_range(TA1IV,14))
  {
    case  0: break;                          // No interrupt
    case  2: break;                          // CCR1 not used
    case  4: break;                          // CCR2 not used
    case  6: break;                          // reserved
    case  8: break;                          // reserved
    case 10: break;                          // reserved
    case 12: break;                          // reserved
    case 14: P1OUT ^= 0x01;                  // overflow
             break;
    default: break; 
  }
}