写了个PWM捕获的，

strednly

初始化函数void trapping()
{

TIM_ICInitTypeDef TIM_ICInitStructure;
GPIO_InitTypeDef   GPIO_InitStructure;

RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC | RCC_APB2Periph_AFIO, ENABLE);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM3,ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
GPIO_Init(GPIOC, &GPIO_InitStructure);

TIM_ICInitStructure.TIM_Channel = TIM_Channel_1;
TIM_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
TIM_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
TIM_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
TIM_ICInitStructure.TIM_ICFilter = 0x00;
TIM_ICInit(TIM3,&TIM_ICInitStructure);
TIM_Cmd(TIM3, ENABLE);
TIM_ITConfig(TIM3, TIM_IT_CC1,ENABLE);//????????
}
中断函数
void TIM3_IRQHandler()
{
if(TIM_GetITStatus(TIM3, TIM_IT_CC1)==SET)
{
TIM_ClearFlag(TIM3, TIM_FLAG_CC1);
if(flag1==0)
{
   ic1readvalue1=TIM_GetCapture1(TIM3);
   flag1=1;
}
else if(flag1==1)
{
ic1readvalue2=TIM_GetCapture1(TIM3);
if(ic1readvalue1>ic1readvalue2)
{
    lasttime=((0xffff-ic1readvalue1)+ic1readvalue2);
}
else
{
    lasttime=(ic1readvalue2-ic1readvalue1);
    }
frequence=(u32)SystemCoreClock/ic1readvalue1;
flag1=0;
printf("%d\r\n",ic1readvalue1);
}
}
}
这样采集到的ic1readvalue1和ic1readvalue2的值相同，怎么计算高电平持续时间啊。。。。。。

正点原子

说明你的采集方法有问题，楼主可以参考下我们的输入捕获例程。