HAL_UART_RxCpltCallback() doesn't trigger

[LBiss.1]

I am working on a STL32F401RET6 MCU and the HAL_UART_RxCpltCallback() doesn't work even though I turned the global interrupt on.

Here is my code for the callback functions :

  void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
    {
	  HAL_GPIO_TogglePin(GPIOA, LD2_Pin);
 
  	  HAL_Delay(1000);
  	  HAL_GPIO_TogglePin(GPIOA, LD2_Pin);
    }
 
  void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
      {
  	  	  HAL_GPIO_TogglePin(GPIOA, LD2_Pin);
  	  	  HAL_Delay(1000);
  	  	  HAL_GPIO_TogglePin(GPIOA, LD2_Pin);
      }

And this is the code I'm trying to run, which should trigger the callback functions :

char recep[]="";
 
HAL_UART_Receive_IT(&huart2, recep, 1);
HAL_Delay(3000);
recep[1]='b';
HAL_UART_Transmit_IT(&huart2,recep,2);
 
while (1);

I have an Hercules terminal running and the communication works alright, I just don't get why the callback functions won't fire.

void USART2_IRQHandler(void)
{
  /* USER CODE BEGIN USART2_IRQn 0 */
 
  /* USER CODE END USART2_IRQn 0 */
  HAL_UART_IRQHandler(&huart2);
  /* USER CODE BEGIN USART2_IRQn 1 */
 
  /* USER CODE END USART2_IRQn 1 */
}

Here is my USART2_IRQHandler() as well. I checked the stm32f4xx_hal_conf and stm32f4xx_it files and both the IRQHandler and UART module are functional.

Is there something I forgot ?

[Anwar.786]

Try adding this in your callback function HAL_UART_Receive_IT(&huart2, recep, 1);

callback function should look like this

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)

{

HAL_UART_Receive_IT(&huart2, recep, 1);

HAL_GPIO_TogglePin(GPIOA, LD2_Pin);

HAL_Delay(1000);

HAL_GPIO_TogglePin(GPIOA, LD2_Pin);

}

once you tried the above method let me know the status

[Karl Yamashita]

You can't use HAL_Delay inside an interrupt. Until you exited HAL_UART_RxCpltCallback the HAL_Delay is going to stay stuck because the systick can't interrupt. Same for HAL_UART_TxCpltCallback.

Set a flag in HAL_UART_RxCpltCallback. Check the flag in main while loop and do what you need to do there.

[Karl Yamashita]

Here is an example of using flags and doing everything outside of an interrupt.

volatile bool dataRdyFlag = false;
volatile bool txDoneFlag = false;
char recep[2] = {0};
volatile bool rxIntErrorFlag = false;
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
	if(huart->Instance == huart2.Instance)
	{
		dataRdyFlag = true;
		EnableRxInterrup();
	}
}
 
void HAL_UART_TxCpltCallback(UART_HandleTypeDef *huart)
{
	txDoneFlag = true;
}
 
void EnableRxInterrup(void)
{
	if(HAL_UART_Receive_IT(&huart2, (uint8_t*)recep, 1) != HAL_OK)
	{
		rxIntErrorFlag = true;
	}
}
 
int main(void)
{
	EnableRxInterrup();
	while(1)
	{
		if(dataRdyFlag)
		{
			dataRdyFlag = false;
 
			recep[1] = 'b';
			HAL_UART_Transmit_IT(&huart2,(uint8_t*)recep,2);
 
 
			HAL_GPIO_TogglePin(GPIOA, LD2_Pin);
 
			HAL_Delay(1000);
			HAL_GPIO_TogglePin(GPIOA, LD2_Pin);
		}
		if(txDoneFlag)
		{
			txDoneFlag = false;
			HAL_GPIO_TogglePin(GPIOA, LD2_Pin);
			HAL_Delay(1000);
			HAL_GPIO_TogglePin(GPIOA, LD2_Pin);
		}
		if(rxIntErrorFlag)
		{
			rxIntErrorFlag = false;
			EnableRxInterrup();
		}
	}
}

You should check this video on blinking an LED using TimerCallback. This eliminates using HAL_Delay which is blocking code. The video is more on debouncing a push button but it also goes a little bit into blinking an LED at different rates

ttps://youtu.be/o0qhmXR5LD0