我用Timer3做pwm输出,然后Timer2捕捉这个pulse输出,当pulse输出占空比大于50%时可以正常进入中断,但小于时进不能进入中断,也就是红色 CCR3_Val =18;改为 CCR3_Val =36时,就不能进入中断(注输出是经过三极管反向了) void IRQ_Tim2(void) { volatile unsigned short IC2Value = 0; volatile unsigned short IC1Value = 0; if(TIM_GetITStatus(TIM2, TIM_IT_CC2) == SET) { TIM_ClearITPendingBit(TIM2, TIM_IT_CC2); IC2Value = TIM_GetCapture2(TIM2); IC1Value = TIM_GetCapture1(TIM2); if(start==1) { if(count |