STM32F4 interrupt handler for capture its not called

Question

The code below uses the capture compare feature of TIM1 channel 3 to capture rising edge on PE10, but its not working, the interrupt handler its not called. I am not that good at this embedded stuff, so can somebody tell me if I am settings this correctly ?

#include "STM32/stm32f4xx_tim.h"

void TIM1_Config(void)
{
  GPIO_InitTypeDef GPIO_InitStructure;
  NVIC_InitTypeDef NVIC_InitStructure;

  /* TIM1 clock enable */
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_TIM1, ENABLE);

  /* GPIOA clock enable */
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);

  /* TIM1 channel 3 pin (PE.10) configuration */
  GPIO_InitStructure.GPIO_Pin =  GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOE, &GPIO_InitStructure);

  /* Connect TIM pins to AF2 */
  GPIO_PinAFConfig(GPIOE, GPIO_PinSource10, GPIO_AF_TIM1);

  /* Enable the TIM1 global Interrupt */
  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);

  TIM_ICInitTypeDef  TIM_ICInitStructure;
  TIM_ICInitStructure.TIM_Channel = TIM_Channel_3;
  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_ICInit(TIM1, &TIM_ICInitStructure);

  /* TIM enable counter */
  TIM_Cmd(TIM1, ENABLE);

  /* Enable the CC3 Interrupt Request */
  TIM_ITConfig(TIM1, TIM_IT_CC3, ENABLE);
}


void TIM1_CC_IRQHandler(void)
{
    // .................
}

int StartCapture()
{ 
  TIM1_Config();

  while(1); /* Infinite loop */
}

Answer 1

If your TIM1_CC_IRQHandler() is getting called ONCE, then Dracog71's answer is correct. However, if your IRQHandler() is never firing, then there's something wrong in the initialization.

Here's a list of things you have to get right or the IRQ won't fire.

1) Make sure that the GPIO[A:E] clock is enabled for the pin you are using.

2) Likewise, make sure the clock is enabled for the TIMx you are using. Check where your TIMx lives. If you call RCC_APB2PeriphClockCmd() for a timer that lives on APB1, the compiler won't throw an error, but your timer will never work.

3) Double-check your pin's AF matches the datasheet's Alternative Function Mapping table (eg. AF1 == TIM1_CH3).

4) In your TIM_ICInitStructure, make sure TIM_Channel matches the channel you have chosen (in your case TIM_Channel_3).

5) Configure and enable the correct IRQ channel in the NVIC, eg. NVIC_InitStructure.NVIC_IRQChannel = TIM1_CC_IRQn;

6) Enable the interrupt: TIM_ITConfig(TIM1, TIM_IT_CC3, ENABLE);

7) Enable your timer: TIM_Cmd(TIM1, ENABLE);