STM32L0 GPIO Interrupt does not work

Question

I am trying to blink the led on GPIO PA5 port, every time when PC13 Button is clicked. However, it does not work. Could you please advice, how can i solve the problem?

main.c - main program

#include "main.h"
#include "stm32l0xx_hal.h"

void SystemClock_Config(void);
static void MX_GPIO_Init(void);

int main(void)
 {
   HAL_Init();
   SystemClock_Config();
   MX_GPIO_Init();

   while (1)
    {
    }
  }

GPIO port conficuration section. PA5 and PC13 ports are configured. Interrupt on EXTI13 enabled.

static void MX_GPIO_Init(void)
  {

    GPIO_InitTypeDef GPIO_InitStruct;

   /* GPIO Ports Clock Enable */
    __HAL_RCC_GPIOC_CLK_ENABLE();
    __HAL_RCC_GPIOA_CLK_ENABLE();

   /*Configure GPIO pin Output Level */
   HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);

  /*Configure GPIO pin : PC13 */
  GPIO_InitStruct.Pin = GPIO_PIN_13;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
  GPIO_InitStruct.Pull = GPIO_PULLUP;
  HAL_GPIO_Init(GPIOC, &GPIO_InitStruct);

  /*Configure GPIO pin : PA5 */
  GPIO_InitStruct.Pin = GPIO_PIN_5;
  GPIO_InitStruct.Mode = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /* EXTI interrupt init*/
  HAL_NVIC_SetPriority(EXTI4_15_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(EXTI4_15_IRQn);
}

stm32l0xx_it.c - interrupt file. IRQ handler and Callback function defined.

void EXTI4_15_IRQHandler(void)
 {
    HAL_GPIO_EXTI_IRQHandler(GPIO_PIN_13);
 }

void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin){
    HAL_GPIO_TogglePin(GPIOA, GPIO_PIN_5);
    HAL_Delay(500);
}

Best regards,

Answer 1

I don't understand what you want to do.

• If you want to change the state of your LED on each push button event, you don't need to put a delay in the HAL_GPIO_EXTI_Callback . It's not a good practice in firmware development. IRQs are supposed to manage events quickly. Their processes have a higher priority than the program execution (here, your main).

  \nvoid HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) \n{ \n    if(GPIO_Pin == GPIO_PIN_13) \n    { \n        HAL_GPIO_TogglePin (GPIOA, GPIO_PIN_5); \n    } \n} \n

• If you want to start/stop blinking your LED based on push button events, you need to use a timer (eg the button start a timer, each timer elapsed irq toggles PA5).

In MX_GPIO_Init function, you have to call HAL_GPIO_WritePin after the PA5 initialization ( HAL_GPIO_Init ).

Take a look to your hardware before setting a pullup on PA13.

I advise you to download STM32Cube . They are lot of code samples. An example shows how to configure external interrupt lines to blink a LED on button events (repository path: ...\\STM32Cube\\Repository\\STM32Cube_FW_L0_V1.8.0\\Projects\\STM32L073RZ-Nucleo\\Examples\\GPIO\\GPIO_EXTI ).

Answer 2

HAL_Delay() will not work until you change priority of exti irq to be higher then priority of systick irq. In your implementation, I assume, default priorities are 0 for both and HAL_Delay() hangs because you use it in same isr priority. Try to change exti irq priority to 1.