下面的代码求指导，或者有哪位大神会msp430g2553实现两个捕获口来求时间差，求帮助~

#include <msp430g2553.h>
#include "12864ser.h"
//#include "math.h"

unsigned int capture0_value = 0;
unsigned int capture1_value = 0;
float diff_time_value = 0;
float diff_distance = 0;
unsigned char flag_cnt = 0;

void main()
{
  unsigned char s1[] ={"声音定位系统"};
  unsigned char s2[] ={"X 轴:"};
  unsigned char s3[] ={"Y 轴:"};
  WDTCTL = WDTPW + WDTHOLD;          //stop watching dog
  BCSCTL1 = CALBC1_16MHZ;  //设定cpu
  DCOCTL = CALDCO_16MHZ;   //配置DCOCLK产生16M时钟
  BCSCTL2 |= SELM_1 + DIVM_0 + DIVS_0;  //主时钟MCLK选择DCOCLK，不分频.子时钟SMCLK选择DCOCLK，不分频

  P2DIR |= BIT3 + BIT4;       //开输出
  P1DIR &= ~(BIT1 + BIT2 + BIT6 + BIT7);   //four input p1.4~p1.7
  P1SEL |= BIT1 + BIT2;


  TACTL = TASSEL_2 + TACLR + MC_1; //SMCLK,up mode
  //capture 0
  TACCTL0 = CCIE + CM_2 + CCIS_0 + CAP + SCS ;    //neg. edge,enabled interrupt,CCIxA,capture mode,            
  //capture 1
  TACCTL1 = CCIE + CM_2 + CCIS_0 + CAP + SCS ;    //neg. edge,enabled interrupt,CCIxA,capture mode,            
  TACCR0 = 16;
  TACCR1 = 16;

  _BIS_SR(GIE);                 // Enter LPM0 w/ interrupt

  init_lcd();             //初始化
  delay_ms(10);

      //  wr_string(uchar x,uchar y0,uchar *p);
    wr_string(1,0,s1);   //第二个参数是行号
    delay_ms(1000);
    wr_string(0,1,s2);
    delay_ms(1000);
    wr_string(0,2,s3);
    delay_ms(1000);
    wr_float(3,1,123.564);
    delay_ms(1000);
    wr_float(3,2,169.2145);
    delay_ms(1000);

  while (1)
  {
    if (flag_cnt == 2)
    {
      flag_cnt = 0;          //clear flag
      if(capture0_value - capture1_value <= 0)
        diff_time_value = capture1_value - capture0_value;
      else
        diff_time_value = capture0_value - capture1_value;
      diff_distance = diff_time_value *340 * 1.087 / 1000;    //uints:mm
    }
  }
}

#pragma vector = TIMER0_A0_VECTOR
__interrupt void Timer_A0 (void)
{
  switch (TAIV)
  {
  case 0x02:
    capture1_value = TACCR1;
    flag_cnt++;
  case 0x04:break;   //capture 2
  case 0x0a:break;
  }
}

#pragma vector = TIMER0_A1_VECTOR
__interrupt void Timer_A1 (void)
{
  capture0_value = TACCR0;
  flag_cnt++;
} 此帖出自小平头技术问答