4.9.c

MSP430单片机的经典C语言例子

#include <msp430x14x.h>
 
unsigned int    start ,end;
unsigned char   overflow;
 
void main(void)
{
      WDTCTL  =  WDTPW+WDTHOLD;
      P1DIR   =  BIT0+BIT4;
      P1SEL  |=  BIT2;
      TACTL   =  TASSEL0+TACLR+TAIE+MC1;
      CCTL1   =  CM0+SCS+CAP+CCIE;
      _EINT();
      while(1); 
    
} 

#pragma vector=TIMERA1_VECTOR
__interrupt  void Time_A1 (void)
{
    switch(TAIV)
     {
       case 2:
          if(CCTL1&CM0)
              {
                CCTL1  =  (CCTL1&(~CM0))|CM1;
                start  =  TAR;
                overflow =0; 
              }
           else if(CCTL1&CM1)
              {
                 CCTL1  =  (CCTL1&(~CM1))|CM0;
                 end    =   TAR;
              }
        break;
        
      case 10:
           overflow++;
           break;
      default:break;              
     }
}