配置代码如下，有个PWM信号需要输入捕获计算频率，经查询数据手册PB11可以复用为TIM2_CH4,但怎么配置都不能正常进捕获中断，IC和PWM方式都试了不行，想问各位大佬该配置有啥问题，有没有什么解决办法
/*功能名称IM4_PWMINPUT_INIT(u16 arr,u16 psc)
描述      PWM输入初始化*/
void TIM2_PWMINPUT_INIT(u16 arr, u16 psc)
{
    TIM_TimeBaseInitTypeDef  TIM_TimeBaseStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
    TIM_ICInitTypeDef  TIM2_ICInitStructure;
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM2, ENABLE);     //Open TIM4 clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);  //open gpioB clock
    GPIO_PinRemapConfig(GPIO_PartialRemap2_TIM2,ENABLE);       
       
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
       
        /*配置中断优先级*/
    NVIC_InitStructure.NVIC_IRQChannel = TIM2_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 1;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
       
    TIM_TimeBaseStructure.TIM_Period = arr; //设置在下一个更新事件装入活动的自动重装载寄存器周期的值
    TIM_TimeBaseStructure.TIM_Prescaler = psc; //设置用来作为TIMx时钟频率除数的预分频值
    TIM_TimeBaseStructure.TIM_ClockDivision = 0; //设置时钟分割:TDTS = Tck_tim
    TIM_TimeBaseStructure.TIM_CounterMode = TIM_CounterMode_Up;  //TIM向上计数模式
    TIM_TimeBaseInit(TIM2, &TIM_TimeBaseStructure); //根据TIM_TimeBaseInitStruct中指定的参数初始化TIMx的时间基数单位

    TIM2_ICInitStructure.TIM_Channel = TIM_Channel_4;
    TIM2_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
    TIM2_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
    TIM2_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;
    TIM2_ICInitStructure.TIM_ICFilter = 0x00;

    TIM_ICInit(TIM2, &TIM2_ICInitStructure);
//    TIM_PWMIConfig(TIM2, &TIM2_ICInitStructure);     //PWM输入配置

//    TIM_SelectInputTrigger(TIM2, TIM_TS_TI1FP1);     //选择有效输入端
//    TIM_SelectSlaveMode(TIM2, TIM_SlaveMode_Reset);  //配置为主从复位模式
//    TIM_SelectMasterSlaveMode(TIM2, TIM_MasterSlaveMode_Enable);


    TIM_ITConfig(TIM2,TIM_IT_CC3 | TIM_IT_CC4, ENABLE);        //中断配置
    TIM_ClearITPendingBit(TIM2,TIM_IT_CC3 | TIM_IT_CC4); //清除中断标志位
               
    TIM_Cmd(TIM2, ENABLE);
}

void TIM2_IRQHandler(void)
{
    if (TIM_GetITStatus(TIM2, TIM_IT_CC3) != RESET) { //捕获1发生捕获事件
                       
    }
    if (TIM_GetITStatus(TIM2, TIM_IT_CC4) != RESET) { //捕获1发生捕获事件
                       
    }
    TIM_ClearITPendingBit(TIM2, TIM_IT_CC3 | TIM_IT_CC4 |TIM_IT_Update); //清除中断标志位
}