First call of timer expires immediately

[SriramK34]

Hi,

I am trying to check if a button is pressed for 3s continuously using a timer which is started through an interrupt. The code for the same is attached below. The issue I am facing is the interrupt is immediately called when I press the button after reset, but it works fine for the consecutive times. 

void EXTI1_IRQHandler(void) {

	if (__HAL_GPIO_EXTI_GET_IT(RESET_Pin) != RESET) {
		__HAL_GPIO_EXTI_CLEAR_IT(RESET_Pin); // Clear the interrupt flag

		if( HAL_GPIO_ReadPin(RESET_GPIO_Port, RESET_Pin) == 0){ //FALLING Edge
			HAL_TIM_Base_Stop_IT(&htim2);
		}else{ //RISING EDGE
			if(!(TIM2->CR1 & TIM_CR1_CEN)){
				__HAL_TIM_SET_COUNTER(&htim2, 0);
				HAL_TIM_Base_Start_IT(&htim2);
			}
		}
	}
}

void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
{
 /* USER CODE BEGIN Callback 0 */

 /* USER CODE END Callback 0 */
 if (htim->Instance == TIM8) {
 HAL_IncTick();
 }
 /* USER CODE BEGIN Callback 1 */
	if(htim->Instance == TIM2){
		HAL_TIM_Base_Stop_IT(htim);
		osSemaphoreRelease(task_semaphore);
		return;
	}
 /* USER CODE END Callback 1 */
}

 

Things I have already tried:

• Set the counter to zero at the when initializing it.
• Calling stop before starting the timer

 

Thanks in advance!

[TDK]

Timer ARR and PSC are preloaded. Generate an update event after you change them and clear the UIF flag.