STM32VLDiscovery Timer Interrupt HardFault c

Question

I've tried to write a short program using the stm32 timer interrupt on the stm32f100rbt6 on a STM32VLDiscovery board.

This is the code I have so far (main.c):

static inline void initGPIO() {
    RCC->APB2ENR |= RCC_APB2ENR_IOPCEN;
    GPIO_InitTypeDef init;
    init.GPIO_Mode = GPIO_Mode_Out_PP;
    init.GPIO_Speed = GPIO_Speed_2MHz;
    init.GPIO_Pin = 0xFFFF;
    GPIO_Init(GPIOC, &init);
}

static inline void initTimer3() {
    NVIC_EnableIRQ(TIM3_IRQn);
    RCC->APB1ENR |= RCC_APB1ENR_TIM3EN;
    TIM3->SR = 0;
    TIM3->ARR = 0xFFFF;
    TIM3->PSC = 0xFFFF;
    TIM3->DIER = TIM_DIER_UIE;
    TIM3->CR1 |= TIM_CR1_CEN;
    //same problem when I enable the IRQ here
}

int main(void) {
    SCB->CCR |= SCB_CCR_STKALIGN;
    SystemInit();

    initGPIO();

    GPIOC->ODR = 0xFFFF;

    initTimer3();

    for (;;) {
        GPIOC->BSRR = ~(TIM3->CNT >> 8) & 0x7F;
        GPIOC->BRR = (TIM3->CNT >> 8) & 0x7F;
    }
}

void TIM3_IRQHandler() {
    TIM3->SR = 0;
    //GPIOC->ODR = 0xCC;
}

void HardFault_Handler() {
    GPIOC->BRR = 0x100;
    while (1)
        ;
}

It should call the IRQHandler everytime the timer overflows. When I don't enable the NVIC, then the program runs normally, just writing a part of the timer value to GPIOC. But as soon as I enable the NVIC, the program HardFaults, as soon as the initTimer3 function is called.

What I've tried so far:

Moving the NVIC_EnableIRQ line somewhere else in the function
- Still get the same problem
Adding a delay before calling the initTimer3 function
- Everything before the initTimer3 function gets executed correctly, as soon as the init function is called, the program hardfaults.
Using a Different Timer
- I already tried using TIM7 and TIM6

Update

Setting the STKALIGN bit does not change anything either. The HardFault happens as soon as the Interrupt is activated.

Should you not be enabling the interrupt AFTER configuring the timer registers? Does the timer need to be powered up? — Martin James
I already tried enabling the interrupt after the timer configuration, also tried enabling it just before writing CEN bit to high. — Alexander Daum

0___________ 0___________ · Accepted Answer · 2018-02-07T14:58:18

Another common problem:

The interrupt routine name must much this one in the startup files. For example in the code generated by the Cube MX the vector table is defined in the startup_stm32f103xb.s file. The timer interrupts routines are:

  .word TIM1_BRK_IRQHandler
  .word TIM1_UP_IRQHandler
  .word TIM1_TRG_COM_IRQHandler
  .word TIM1_CC_IRQHandler
  .word TIM2_IRQHandler
  .word TIM3_IRQHandler
  .word TIM4_IRQHandler

Check in your files what names are used in the vector table.

STM32VLDiscovery Timer Interrupt HardFault c

2 Answers