【SIGMA开发小组】STM32F407之PA1不能用作TIM5的CH1通道捕获功！

zszghzszgh-3712

今天调试四轴遥控，需要用到定时器的输入捕获功能，于是配置TIM5如下：
/* Connect TIM pin to AF2 */
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource0, GPIO_AF_TIM5);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource1, GPIO_AF_TIM5);
  GPIO_PinAFConfig(GPIOA, GPIO_PinSource2, GPIO_AF_TIM5);
GPIO_PinAFConfig(GPIOA, GPIO_PinSource3, GPIO_AF_TIM5)；


        TIM5_ICInitStructure.TIM_Channel = TIM_Channel_1;
          TIM5_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;
          TIM5_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
          TIM5_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;       
          TIM5_ICInitStructure.TIM_ICFilter = 0x01;
          TIM_ICInit(TIM5, &TIM5_ICInitStructure);
       
          TIM5_ICInitStructure.TIM_Channel = TIM_Channel_2;
          TIM5_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;       
          TIM5_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
          TIM5_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;       
          TIM5_ICInitStructure.TIM_ICFilter = 0x01;
          TIM_ICInit(TIM5, &TIM5_ICInitStructure);
       
        TIM5_ICInitStructure.TIM_Channel = TIM_Channel_3;
          TIM5_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;       
          TIM5_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
          TIM5_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;       
          TIM5_ICInitStructure.TIM_ICFilter = 0x01;
          TIM_ICInit(TIM5, &TIM5_ICInitStructure);

        TIM5_ICInitStructure.TIM_Channel = TIM_Channel_4;
          TIM5_ICInitStructure.TIM_ICPolarity = TIM_ICPolarity_Rising;       
          TIM5_ICInitStructure.TIM_ICSelection = TIM_ICSelection_DirectTI;
          TIM5_ICInitStructure.TIM_ICPrescaler = TIM_ICPSC_DIV1;       
          TIM5_ICInitStructure.TIM_ICFilter = 0x01;
          TIM_ICInit(TIM5, &TIM5_ICInitStructure);
               
        TIM_ITConfig(TIM5,TIM_IT_CC1,ENABLE);
        TIM_ITConfig(TIM5,TIM_IT_CC2,ENABLE);
        TIM_ITConfig(TIM5,TIM_IT_CC3,ENABLE);
        TIM_ITConfig(TIM5,TIM_IT_CC4,ENABLE);

           TIM_Cmd(TIM5,ENABLE );

按照这样配置完成后，CH1，CH3，CH4都是可以的，正常，但是就CH2不能正常工作，找了半天，未果，后来只有使用另外一种方法来解决捕获的功能，就是再使用一个TIM6来计数，使能PA1的EXIT功能，代码如下：
TIM_Cmd(TIM6, ENABLE);
/* Connect EXTI Line0 to PA0 pin */
  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource1);       
  EXTI_InitStructure.EXTI_Line = EXTI_Line1;
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init(&EXTI_InitStructure);        
这样终于解决了问题，四个 通道的PPM信号就可以能够捕获到了！！！
再次重申一下PA1不能用于TIM5的捕获功能。。。{:soso_e100:}{:soso_e100:}{:soso_e100:}，希望我们好运！！！

xiaoyao4536

赞一个！！

Xwzc0bm0

谢谢分享哈

luozuoyong

stm32f407的PA1是确定可以用于TIM5或者TIM2的捕捉功能的，解决办法就是在初始化GPIO的时候，加入上下拉。GPIO_PuPd_DOWN和GPIO_PuPd_UP都可以，不能是GPIO_PuPd_NOPULL。