关于msp430定时一秒捕获测频率

定时使用32Khz的时钟,捕获使用8M的SMCLK,但是每次结果都是32K???

时钟设置

float count = 0.0;

void ClkInit()
{  
    char i;
    BCSCTL1 &= ~XT2OFF;             //打开XT2振荡器
    IFG1&=~OFIFG;                   //清除振荡错误标志
    while((IFG1&OFIFG)!=0)
    {
        for(i=0;i<0xff;i++);
        IFG1&=~OFIFG;               //清除振荡错误标志
    }
    BCSCTL2 |= SELM_2+SELS+DIVS_0;  //MCLK为8MHz，SMCLK为8MHz
}

捕获模式设置
void Init_cap(void)
{
    P1SEL  |=0x04;               //选择P1.2作为捕获的输入端子
    TACCTL1|=CM0+SCS+CCIS_0+CAP+CCIE;//上升沿触发，同步模式，使能中断
    TACTL  |=TASSEL1+ID_0;   //选择8M－SMCLK时钟
}

定时设置

void Init_timer_b(void)
{
  TBCCTL0 = CCIE;                           // CCR0 interrupt enabled
  TBCCR0 = 64000;                           //定时2秒
  TBCTL = TBSSEL_1 + MC_1;                  // ACLK, upmode
}
int main( void )
{
  //Stop watchdog timer to prevent time out reset
  WDTCTL = WDTPW + WDTHOLD;
  ClkInit();  //初始化时钟MCLK 8MHZ,SMCLK 8MHZ
  P5DIR |= 0X60;
  P5SEL |= 0X60;
  LcdInit();
  LcdWriteString(0x80,"欢迎");
  Init_cap();
  Init_timer_b();
  _EINT();
  while(1);
}

#pragma vector=TIMERA1_VECTOR
__interrupt void Timer_A(void)
{
    switch(TAIV)
    {
    case 2:
      {
        count++;
        break;
      };
    case 4: 
      break;
    case 10:
      break;
    }
 
}
#pragma vector=TIMERB0_VECTOR
__interrupt void Timer_B (void)
{
    TACCTL1 &= ~(CCIE);//关闭捕获中断
    TBCCTL0 &= ~(CCIE); //关闭定时中断
    P2DIR |= 0XFF;
    P2OUT ^= BIT0;
    count = (count/2000.0);
    fenli(count);
    LcdWriteString(0x90,"频率:");
    LcdWriteData(baiwei);
    LcdWriteData(shiwei);
    LcdWriteData(gewei);
    LcdWriteData(0x2e);  //此处显示一个.
    LcdWriteData(yiwei);
    LcdWriteData(lianwei);
    LcdWriteString(LcdReadAddr()+0x01,"KHz");
}