fet430_wdt02.c

msp430开发c语言例程

//******************************************************************************
//  MSP-FET430P430 Demo - WDT Toggle P5.1 Interval overflow ISR, 32kHz ACLK
//
//  Description; Toggle P5.1 using software timed by WDT ISR. Toggle rate is 
//  exactly 250ms based on 32kHz ACLK WDT clock source.  In this example the 
//  WDT is configured to divide 32768 watch-crystal(2^15) by 2^13 with an ISR 
//  triggered @ 4Hz.  
//  ACLK = LFXT1 = 32768, MCLK = SMCLK = DCO
//  //*External watch crystal installed on XIN XOUT is required for ACLK*//	  
//
//		  MSP430FG439
//             -----------------
//         /|\|              XIN|-  
//          | |                 | 32kHz
//          --|RST          XOUT|-
//            |                 |
//            |             P5.1|-->LED
//
//  M.Buccini
//  Texas Instruments, Inc
//  June 2004
//  Built with IAR Embedded Workbench Version: 2.21B
//******************************************************************************

#include  <msp430xG43x.h>

void main(void)
{ 
  WDTCTL = WDT_ADLY_250;                // WDT 250ms, ACLK, interval timer
  IE1 |= WDTIE;                         // Enable WDT interrupt
  FLL_CTL0 |= XCAP14PF;                 // Configure load caps
  P5DIR |= 0x02;                        // Set P5.1 to output direction

  _BIS_SR(LPM3_bits + GIE);             // Enter LPM3 w/interrupt
}

// Watchdog Timer interrupt service routine
#pragma vector=WDT_VECTOR
__interrupt void watchdog_timer(void)
{
  P5OUT ^= 0x02;                        // Toggle P5.1 using exclusive-OR
}