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Problem enabling timer in STM32F103

Question asked by dan on Jul 17, 2015
Latest reply on Jul 21, 2015 by dan
Hi all,

I am using a STM32F103 MCU and I wanted to enable TIM2 timer and then perform some operations upon signals received by the timer, first by polling and then using interrupts. I have setup my timer i.e. TIM2 as below:

  TIM_TimeBaseInitTypeDef TIM_InitStruct;

  // Configure TIM2 internal timer.
  TIM_InitStruct.TIM_Prescaler = 40000;
  TIM_InitStruct.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_InitStruct.TIM_Period = 500;
  TIM_InitStruct.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_InitStruct.TIM_RepetitionCounter = 0;
  TIM_TimeBaseInit(TIM2, &TIM_InitStruct);

  // Enable TIM2 internal timer.

Than I tried to trigger an interrupt based on TIM2 timer using the following code:

  NVIC_InitTypeDef NVIC_InitStruct;


  // Enable TIM2 interrupt.
  NVIC_InitStruct.NVIC_IRQChannel = TIM2_IRQn;
  NVIC_InitStruct.NVIC_IRQChannelPreemptionPriority = 0;
  NVIC_InitStruct.NVIC_IRQChannelSubPriority = 1;
  NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;

  void TIM2_IRQHandler() {
    // Do something here by toggling bits for a LED.

My code never worked and the LED never turned on. So, I tried to perform polling within the infinite loop in the main function as below:

  while(1) {
    if (TIM_GetITStatus(TIM2, TIM_IT_Update) != RESET) {
      TIM_ClearITPendingBit(TIM2, TIM_IT_Update);
      // Do something here by toggling bits for a LED.

And again, my code didn't work with polling approach neither. Am I doing something wrong in both cases i.e. interrupt- and polling-based solutions? It should be quite straightforward to use a timer in both ways (interrupt and polling´) so I am wondering what is wrong in my code? Can anybody help me with that?