捕获pwm数值总是为零 为什么

般若888

u32 IC2Value;
u32 Frequency;
u32 DutyCycle;
u32 speed;

void PWM_Input_Init(void)
{
TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
TIM_ICInitTypeDef  TIM_ICInitStructure;
GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA , ENABLE);  //使能GPIO外设和AFIO复用功能模块时钟


    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_1;
    GPIO_InitStructure.GPIO_Mode=GPIO_Mode_AF;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL; //浮空
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

//注意一定不要忘了配置TIM_TimeBaseInit()，每次只要使用定时器的任何模式，都需要使用TIM_TimeBaseInit()
//不要在定时器2里面配置过了，在这个定时器3的配置程序中就忘了，他们是互不影响的
TIM_TimeBaseStructure.TIM_Period = 65535;
TIM_TimeBaseStructure.TIM_Prescaler = 71;
TIM_TimeBaseStructure.TIM_ClockDivision = 0;
TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;
TIM_TimeBaseInit(TIM3, &TIM_TimeBaseStructure);

GPIO_PinAFConfig(GPIOA,GPIO_PinSource1,GPIO_AF_TIM5); //GPIOA1复用为定时器5
  
NVIC_InitStructure.NVIC_IRQChannel = TIM5_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
     
    TIM_ICInitStructure.TIM_Channel = TIM_Channel_2;
    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 = 0x0;
    TIM_PWMIConfig(TIM5, &TIM_ICInitStructure);

    TIM_SelectInputTrigger(TIM5, TIM_TS_TI1FP1);
    TIM_SelectSlaveMode(TIM5, TIM_SlaveMode_Reset);
    TIM_SelectMasterSlaveMode(TIM5, TIM_MasterSlaveMode_Enable);
    TIM_Cmd(TIM5, ENABLE);
    TIM_ITConfig(TIM5, TIM_IT_CC1,ENABLE);
}
//4、读取PWM波的中断服务函数：
void TIM5_IRQHandler(void)
{
  TIM_ClearITPendingBit(TIM5, TIM_IT_CC2);
  IC2Value = TIM_GetCapture2(TIM5);
  if (IC2Value != 0)
  {
    DutyCycle = (TIM_GetCapture2(TIM5) * 100) / IC2Value;
    Frequency = SystemCoreClock / IC2Value;
  }
  else
  {
    DutyCycle = 0;
    Frequency = 0;
  }
}

peng1554

如果参考原子输入捕获的定时器配置怎样？