MSP430F149 定时器A捕获功能测脉冲宽度 各位大神帮忙看看哪出了问题？程序如下
/****测脉冲宽度并用1602显示出来****/
#include <msp430x14x.h>
#include "cry1602.c"
#define uint unsigned int
#define uchar unsigned char
uint pwm_star,pwm_end;
uint width;
uint i=0;
uchar *s="The width is :";
uchar b[]={'0','1','2','3','4','5','6','7','8','9'};
uint m,n,p,q;
void main(void)
{
WDTCTL=WDTPW+WDTHOLD;
P6DIR |= BIT2;P6OUT |= BIT2; //关闭电平转换
P6DIR |= BIT3;P6OUT |= BIT3;
BCSCTL1 &= ~XT2OFF; //打开XT2高频晶体振荡器
do
{
IFG1 &= ~OFIFG; //清除晶振失败标志
for (i = 0xFF; i > 0; i--); //等待8MHz晶体起振
}
while ((IFG1 & OFIFG)); //晶振失效标志仍然存在？
BCSCTL2 |= SELM_2 + SELS; //MCLK和SMCLK选择高频晶振
P1DIR|=BIT2;
P1SEL|=BIT2; //捕获源为P1.2
TACTL=TACLR; //定时器清零
TACTL |= TASSEL_2 + ID_3; //计数时钟选择SMLK=8MHz，1/8分频后为1MHz
TACCTL1 =CM_3+SCS+CAP+CCIS_0+CCIE; //上升沿下降沿都同步捕获
TACTL = MC_2; //定时器计数开始 连续计数模式
_EINT();
LcdReset();
DispStr(0,0,s);
while(1)
{
m=width/1000;
n=(width/100)%10;
p=(width/10)%10;
q=width%10;
Disp1Char(4,1,b[m]);
Disp1Char(5,1,b[n]);
Disp1Char(6,1,b[p]);
Disp1Char(7,1,b[q]);
}
}
/******定时器TA的CCR1的中断 用于检测脉冲上升沿和下降沿******/
#pragma vector=TIMERA1_VECTOR
__interrupt void Timer_A1(void)
{
switch(TAIV)
{ case 0x02:
if(CCI==1)
{
pwm_star = TACCR1;
break;
}
else
{
pwm_end = TACCR1;
break;
}
default:
break;
}
width = pwm_end-pwm_star;
} |
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