STM32 HAL timer interrupt isn't triggered

Question

I'm trying to periodically send and Serial string from my STM32F746ZG device, using an interrupt. Most of the code is auto generated by stm32cubemx. I have hardware breakpoints (jlink) set at each interrupt but I only enter the period elapse function once, at initialization. When I randomly pause the debugger I see the counter values between 0 and 1000 as expected. So I know the counter resets every second. The internal clock runs at 16MHz.

My experience with embedded devices is limited to BBB, Raspberry and Arduino's. I tried different examples and tutorials, but at the moment I just don't know anymore. Any help or suggestions is much appreciated.

my main function:

int main(void) {

    HAL_Init();
    SystemClock_Config();
    MX_GPIO_Init();
    MX_RTC_Init();
    MX_TIM1_Init();

    if (HAL_TIM_Base_Start(&htim1) != HAL_OK) {
        Error_Handler();
    }

    if (HAL_TIM_Base_Start_IT(&htim1) != HAL_OK) {
        Error_Handler();
    }

    while (1) {
        cnt = __HAL_TIM_GetCounter(&htim1);
    }
}

TIM1 init:

static void MX_TIM1_Init(void) {

    TIM_ClockConfigTypeDef sClockSourceConfig;
    TIM_MasterConfigTypeDef sMasterConfig;

    htim1.Instance = TIM1;
    htim1.Init.Prescaler = 16000;
    htim1.Init.CounterMode = TIM_COUNTERMODE_UP;
    htim1.Init.Period = 1000;
    htim1.Init.ClockDivision = TIM_CLOCKDIVISION_DIV1;
    htim1.Init.RepetitionCounter = 0x0;
    if (HAL_TIM_Base_Init(&htim1) != HAL_OK) {
        Error_Handler();
    }

    sClockSourceConfig.ClockSource = TIM_CLOCKSOURCE_INTERNAL;
    if (HAL_TIM_ConfigClockSource(&htim1, &sClockSourceConfig) != HAL_OK) {
        Error_Handler();
    }

    sMasterConfig.MasterOutputTrigger = TIM_TRGO_RESET;
    sMasterConfig.MasterOutputTrigger2 = TIM_TRGO2_RESET;
    sMasterConfig.MasterSlaveMode = TIM_MASTERSLAVEMODE_DISABLE;
    if (HAL_TIMEx_MasterConfigSynchronization(&htim1, &sMasterConfig)
            != HAL_OK) {
        Error_Handler();
    }

}

My Base_MspInit function:

void HAL_TIM_Base_MspInit(TIM_HandleTypeDef* htim_base)
{

  GPIO_InitTypeDef GPIO_InitStruct;
  if(htim_base->Instance==TIM1)
  {
    /* Peripheral clock enable */
    __HAL_RCC_TIM1_CLK_ENABLE();
    /* Peripheral interrupt init */
    HAL_NVIC_SetPriority(TIM1_BRK_TIM9_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(TIM1_BRK_TIM9_IRQn);
    HAL_NVIC_SetPriority(TIM1_UP_TIM10_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(TIM1_UP_TIM10_IRQn);
    HAL_NVIC_SetPriority(TIM1_TRG_COM_TIM11_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(TIM1_TRG_COM_TIM11_IRQn);
    HAL_NVIC_SetPriority(TIM1_CC_IRQn, 0, 0);
    HAL_NVIC_EnableIRQ(TIM1_CC_IRQn);
  }
}

My TIM IRQ handler function:

void TIM1_UP_TIM10_IRQHandler(void)
{
  HAL_TIM_IRQHandler(&htim1);
}

HAL IRQ Handler which calls the HAL_TIM_PeriodElapsedCallback:

void HAL_TIM_IRQHandler(TIM_HandleTypeDef *htim)
{
  /* Capture compare 1 event */
  if(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_CC1) != RESET)
  {
    if(__HAL_TIM_GET_IT_SOURCE(htim, TIM_IT_CC1) !=RESET)
    {
      {
        __HAL_TIM_CLEAR_IT(htim, TIM_IT_CC1);
        htim->Channel = HAL_TIM_ACTIVE_CHANNEL_1;

        /* Input capture event */
        if((htim->Instance->CCMR1 & TIM_CCMR1_CC1S) != 0x00)
        {
          HAL_TIM_IC_CaptureCallback(htim);
        }
        /* Output compare event */
        else
        {
          HAL_TIM_OC_DelayElapsedCallback(htim);
          HAL_TIM_PWM_PulseFinishedCallback(htim);
        }
        htim->Channel = HAL_TIM_ACTIVE_CHANNEL_CLEARED;
      }
    }
  }
  /* Capture compare 2 event */
  if(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_CC2) != RESET)
  {
    if(__HAL_TIM_GET_IT_SOURCE(htim, TIM_IT_CC2) !=RESET)
    {
      __HAL_TIM_CLEAR_IT(htim, TIM_IT_CC2);
      htim->Channel = HAL_TIM_ACTIVE_CHANNEL_2;
      /* Input capture event */
      if((htim->Instance->CCMR1 & TIM_CCMR1_CC2S) != 0x00)
      {          
        HAL_TIM_IC_CaptureCallback(htim);
      }
      /* Output compare event */
      else
      {
        HAL_TIM_OC_DelayElapsedCallback(htim);
        HAL_TIM_PWM_PulseFinishedCallback(htim);
      }
      htim->Channel = HAL_TIM_ACTIVE_CHANNEL_CLEARED;
    }
  }
  /* Capture compare 3 event */
  if(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_CC3) != RESET)
  {
    if(__HAL_TIM_GET_IT_SOURCE(htim, TIM_IT_CC3) !=RESET)
    {
      __HAL_TIM_CLEAR_IT(htim, TIM_IT_CC3);
      htim->Channel = HAL_TIM_ACTIVE_CHANNEL_3;
      /* Input capture event */
      if((htim->Instance->CCMR2 & TIM_CCMR2_CC3S) != 0x00)
      {          
        HAL_TIM_IC_CaptureCallback(htim);
      }
      /* Output compare event */
      else
      {
        HAL_TIM_OC_DelayElapsedCallback(htim);
        HAL_TIM_PWM_PulseFinishedCallback(htim); 
      }
      htim->Channel = HAL_TIM_ACTIVE_CHANNEL_CLEARED;
    }
  }
  /* Capture compare 4 event */
  if(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_CC4) != RESET)
  {
    if(__HAL_TIM_GET_IT_SOURCE(htim, TIM_IT_CC4) !=RESET)
    {
      __HAL_TIM_CLEAR_IT(htim, TIM_IT_CC4);
      htim->Channel = HAL_TIM_ACTIVE_CHANNEL_4;
      /* Input capture event */
      if((htim->Instance->CCMR2 & TIM_CCMR2_CC4S) != 0x00)
      {          
        HAL_TIM_IC_CaptureCallback(htim);
      }
      /* Output compare event */
      else
      {
        HAL_TIM_OC_DelayElapsedCallback(htim);
        HAL_TIM_PWM_PulseFinishedCallback(htim);
      }
      htim->Channel = HAL_TIM_ACTIVE_CHANNEL_CLEARED;
    }
  }
  /* TIM Update event */
  if(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_UPDATE) != RESET)
  {
    if(__HAL_TIM_GET_IT_SOURCE(htim, TIM_IT_UPDATE) !=RESET)
    {
      __HAL_TIM_CLEAR_IT(htim, TIM_IT_UPDATE);
      HAL_TIM_PeriodElapsedCallback(htim);
    }
  }
  /* TIM Break input event */
  if(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_BREAK) != RESET)
  {
    if(__HAL_TIM_GET_IT_SOURCE(htim, TIM_IT_BREAK) !=RESET)
    {
      __HAL_TIM_CLEAR_IT(htim, TIM_IT_BREAK);
      HAL_TIMEx_BreakCallback(htim);
    }
  }

    /* TIM Break input event */
  if(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_BREAK2) != RESET)
  {
    if(__HAL_TIM_GET_IT_SOURCE(htim, TIM_IT_BREAK) !=RESET)
    {
      __HAL_TIM_CLEAR_IT(htim, TIM_IT_BREAK);
      HAL_TIMEx_BreakCallback(htim);
    }
  }

  /* TIM Trigger detection event */
  if(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_TRIGGER) != RESET)
  {
    if(__HAL_TIM_GET_IT_SOURCE(htim, TIM_IT_TRIGGER) !=RESET)
    {
      __HAL_TIM_CLEAR_IT(htim, TIM_IT_TRIGGER);
      HAL_TIM_TriggerCallback(htim);
    }
  }
  /* TIM commutation event */
  if(__HAL_TIM_GET_FLAG(htim, TIM_FLAG_COM) != RESET)
  {
    if(__HAL_TIM_GET_IT_SOURCE(htim, TIM_IT_COM) !=RESET)
    {
      __HAL_TIM_CLEAR_IT(htim, TIM_FLAG_COM);
      HAL_TIMEx_CommutationCallback(htim);
    }
  }
}

My callback function:

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim) {
    if (htim->Instance == TIM1) {
        char frame[20] = "123456789012345678\r\n";
        HAL_UART_Transmit(&huart1, frame, 20, 10);
    }
}

Answer 1

The code above was correct. The break points were "temporary hardware" breakpoints, when I changed them to "hardware" breakpoints they where hit when there was a counter overflow indicating that the period was reached.

Typical case of staring at the same code for far too long ;-)