大家好：我使用国民技术的N32G455这款单片机的TM1 //TIM_CH_4做输入捕获，频率17~32K。设置是下降沿触发，但有时候上升沿也会触发，这是什么原因呢？
void pwm_int (void)
{
    GPIO_InitStructure.Pin            = GPIO_PIN_11;//TIM1_CH4
    GPIO_InitStructure.GPIO_Mode      = GPIO_Mode_IN_FLOATING;
    GPIO_InitStructure.GPIO_Speed     = GPIO_Speed_50MHz;

    GPIO_InitPeripheral(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.Pin            = GPIO_PIN_9;//TIM1_CH2
    GPIO_InitStructure.GPIO_Mode      = GPIO_Mode_IN_FLOATING;
    GPIO_InitStructure.GPIO_Speed     = GPIO_Speed_50MHz;

    GPIO_InitPeripheral(GPIOA, &GPIO_InitStructure);

    NVIC_InitType NVIC_InitStructure;
   ADTIMClockFrequency = (GET_RCC_Clocks_Pclk2Freq(TIM1));

    NVIC_InitStructure.NVIC_IRQChannel = TIM1_CC_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

    NVIC_InitStructure.NVIC_IRQChannel = TIM1_UP_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);

#if 1       
        TimerPeriod = (ADTIMClockFrequency / 33000) - 1;
    /* Compute CCDAT1 value to generate a duty cycle at 50% for channel 1 */
    Channel1Pulse = (uint16_t)(((uint32_t)5 * (TimerPeriod - 1)) / 10);

    TIM_TimeBaseStructure1.Prescaler = 0;
    TIM_TimeBaseStructure1.CntMode   = TIM_CNT_MODE_UP;
    TIM_TimeBaseStructure1.Period    = TimerPeriod;
    TIM_TimeBaseStructure1.ClkDiv    = 0;
    TIM_TimeBaseStructure1.RepetCnt  = 0;
    TIM_InitTimeBase(TIM1, &TIM_TimeBaseStructure1);
#endif
    TIM_ICInitStructure.Channel     = TIM_CH_2;
    TIM_ICInitStructure.IcPolarity  = TIM_IC_POLARITY_RISING;
    TIM_ICInitStructure.IcSelection = TIM_IC_SELECTION_DIRECTTI;
    TIM_ICInitStructure.IcPrescaler = TIM_IC_PSC_DIV1;
    TIM_ICInitStructure.IcFilter    = 0x0;

    TIM_ICInit(TIM1, &TIM_ICInitStructure);

#if 1   
    /* TIM1 Input Capture Configuration */
    TIM_ICInitStructure.Channel     = TIM_CH_4;
    TIM_ICInitStructure.IcPolarity  = TIM_IC_POLARITY_RISING;
    TIM_ICInitStructure.IcSelection = TIM_IC_SELECTION_DIRECTTI;
    TIM_ICInitStructure.IcPrescaler = TIM_IC_PSC_DIV1;
    TIM_ICInitStructure.IcFilter    = 0;

    TIM_ICInit(TIM1, &TIM_ICInitStructure);
#endif

    TIM_Output_Channel_Struct_Initialize(&TIM_OCInitStructure);
    /* Channel 1, 2 and 3 Configuration in PWM mode */
    TIM_OCInitStructure.OcMode       = TIM_OCMODE_PWM1;//PWM模式1
    TIM_OCInitStructure.OutputState  = TIM_OUTPUT_STATE_ENABLE;//输出使能
    TIM_OCInitStructure.OutputNState = TIM_OUTPUT_NSTATE_ENABLE;//互补输出使能
    TIM_OCInitStructure.Pulse        = Channel1Pulse;//占空比
    TIM_OCInitStructure.OcPolarity   = TIM_OC_POLARITY_HIGH;//输出有效电平为高电平
    TIM_OCInitStructure.OcNPolarity  = TIM_OCN_POLARITY_HIGH;//互补输出有效电平为高电平
    TIM_OCInitStructure.OcIdleState  = TIM_OC_IDLE_STATE_RESET;//输出空闲时为高电平
    TIM_OCInitStructure.OcNIdleState = TIM_OCN_IDLE_STATE_RESET;//互补输出空闲时为低电平
    TIM_InitOc1(TIM1, &TIM_OCInitStructure);
//#endif     
    TIM_Output_Channel_Struct_Initialize(&TIM_OCInitStructure);

        /* Channel 1, 2 and 3 Configuration in PWM mode */
    TIM_OCInitStructure.OcMode       = TIM_OCMODE_PWM1;//PWM模式1
    TIM_OCInitStructure.OutputState  = TIM_OUTPUT_STATE_ENABLE;//输出使能
    TIM_OCInitStructure.OutputNState = TIM_OUTPUT_NSTATE_DISABLE;//互补输出使能
    TIM_OCInitStructure.Pulse        = Channel1Pulse;//占空比
    TIM_OCInitStructure.OcPolarity   = TIM_OC_POLARITY_LOW;//输出有效电平为高电平
    TIM_OCInitStructure.OcNPolarity  = TIM_OCN_POLARITY_LOW;//互补输出有效电平为高电平
    TIM_OCInitStructure.OcIdleState  = TIM_OC_IDLE_STATE_RESET;//输出空闲时为高电平
    TIM_OCInitStructure.OcNIdleState = TIM_OCN_IDLE_STATE_RESET;//互补输出空闲时为低电平

    TIM_InitOc3(TIM1, &TIM_OCInitStructure);

#if 1
    m_delay_ms(2);

    Half_all_** = GPIO_ReadInputDataBit(GPIOB,GPIO_PIN_7);

    TIM_BDTRInitStructure.OssrState       = TIM_OSSR_STATE_ENABLE; //运行模式下“关闭模式”=1
    TIM_BDTRInitStructure.OssiState       = TIM_OSSI_STATE_ENABLE;//空闲模式下“关闭模式”=1
    TIM_BDTRInitStructure.LockLevel       = TIM_LOCK_LEVEL_1;//锁定级别
    TIM_BDTRInitStructure.DeadTime        = Dead_Time;
    TIM_BDTRInitStructure.Break           = TIM_BREAK_IN_DISABLE;//开启输出功能
    TIM_BDTRInitStructure.BreakPolarity   = TIM_BREAK_POLARITY_HIGH;
    TIM_BDTRInitStructure.AutomaticOutput = TIM_AUTO_OUTPUT_DISABLE;//开启自动输出
    TIM_BDTRInitStructure.IomBreakEn      = true;

    TIM_ConfigBkdt(TIM1, &TIM_BDTRInitStructure);
#endif     

    TIM_ConfigInt(TIM1, TIM_INT_UPDATE|TIM_INT_CC4, ENABLE);
    Fer_test_PWM = 32000;  
    TIM_Enable(TIM1,DISABLE);
}

void TIM1_CC_IRQHandler(void)
{

    if (TIM_GetIntStatus(TIM1, TIM_INT_CC4) == SET)
    {
        TIM_ClrIntPendingBit(TIM1, TIM_INT_CC4);

        TIM1_CH4_count = TIM_GetCap4(TIM1);

   }
}