STM32F411 - Timer interrupt not firing

Question

I setup TIM3 on my STM32F411 using the following code:

void Enable_Timer_3()
{
    __TIM3_CLK_ENABLE();
    TIM3->PSC = 8399;               // Prescaler value, 8400 - 1, 84 MhZ / 8400 = 10000 Hz
    TIM3->EGR = TIM_EGR_UG;         // Update prescaler
    TIM3->ARR = 9999;               // Period, 10000-1, 1 second period
    TIM3->DIER = TIM_DIER_UIE;      // Enable interrupts for this timer
    TIM3->CR1 = TIM_CR1_CEN;        // Enable this timer
}

The timer counts just fine - inspecting the TIM3->CNT register shows it correctly counting from 0 to 9999 in the span of a second. But my interrupt handler is not called.

My handler:

void TIM3_IRQHandler(void)
{
    TIM3->SR = 0;
    HAL_GPIO_TogglePin(LD2_GPIO_Port, LD2_Pin);
}

It is set as the TIM3 interrupt in the interrupt vector:

  .word     TIM3_IRQHandler  /* TIM3 */   

Did I do something wrong?

Answer 1

I do not know much about coding.. but I cannot see the place where you are enabling the interrupts..

The interrupt for timer TIM3 can be enabled by adding the following line to the timer setup function:

NVIC_EnableIRQ(TIM3_IRQn);

Answer 2

I was using CubeMX to generate the code, For some reason the line NVIC_EnableIRQ(TIM3_IRQn); was missing in the timers setup function, adding this solved my issue.