#include "msp430x22x4.h"
//WDT定時器模式下1秒鐘定時
//1秒鐘觸發看門狗定時中斷
//來翻轉P1.0
//                 MSP430F2274
//             -----------------
//         /|\|              XIN|-  
//          | |                 |
//          --|RST          XOUT|-
//            |                 |
//            |             P1.0|-->LED

int main( void )
{
  WDTCTL=WDTPW+WDTHOLD;                   //關看門狗
  BCSCTL1 =CALBC1_1MHZ;                   //設定DCO為1MHZ
  DCOCTL =CALBC1_1MHZ;
  WDTCTL=WDTPW+WDTTMSEL+WDTSSEL+WDTCNTCL; //選擇定時模式,并選時鐘源為ACLK,即定時時間為ACLK/32768(WDTISx=0)
  P1OUT |=BIT0;                           //LED使能
  P1DIR |=BIT0;
  IE1 |=WDTIE;                            //使能WDT定時中斷
  _BIS_SR(GIE+LPM3_bits);                 //進入LPM3模式,ACLK(WDT時鐘源)仍工作,并使能總中斷
  return 0;  
}

#pragma vector=WDT_VECTOR                 //看門狗定時中斷服務
__interrupt void wdt_timer(void)  
{
  P1OUT ^=BIT0;                           //LED翻轉
}