为什么 newcap old cap 里都是0啊 大家帮忙看看

liufeng10101

#include <msp430x14x.h>
unsigned int new_cap=0;
unsigned int old_cap=0;
unsigned int cap_diff=0;
unsigned int diff_array[16];                // RAM array for differences
unsigned int capture_array[16];             // RAM array for captures
unsigned char index=0;
unsigned char count = 0;
#pragma vector=TIMERA0_VECTOR
__interrupt void Timer_A(void)
{   
   new_cap = TACCR0;
   cap_diff = new_cap - old_cap;
   diff_array[index] = cap_diff;            // record difference to RAM array
   capture_array[index++] = new_cap;
   if (index == 16)
   {
     index = 0;
   }
      old_cap = new_cap;                       // store this capture value
  count++;
  if(count==32);
  {
  count=0;
  _NOP();
  }
}
void main(void)
{
unsigned int i;
WDTCTL=WDTPW+WDTHOLD;  
for(i=0;i<20000;i++)
{}
P2DIR=BIT4;
P2SEL=BIT4;
BCSCTL1 |= DIVA_3;
CCTL0=CM_1+SCS+CCIS_0+CAP+CCIE;
TACTL=TASSEL_2+MC_2;
_EINT();
//while(1);
//_BIS_SR(LPM0_bits)+GIE;
}

liufeng10101

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