msp430定时一秒捕获测频率

只看该作者 · 2012-8-17 00:06

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");
}