NUCLEO F411RE external interruption, LED2, Blue button

[Roman_E]

I try to create code, which flashes LED2 ( few flashes , not one toggle ) in response of one press of Blue button.

What could be wrong in my code ? 
Selected two pins PA5 ( input for LED2 ) and PC13 (EXTI for Blue button with External interrupt Mode with Rising edge trigger detection   + no pull up no pull down )   NVIC EXTI line  checkbox - marked.
And Cube IDE generated code with EXTI callback function etc.

In my main.c file, I added this code only:

/* USER CODE BEGIN 4 */
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin) {
	/* Prevent unused argument(s) compilation warning */
	UNUSED(GPIO_Pin);
	if (GPIO_Pin == GPIO_PIN_13) // If The INT Source Is EXTI Line9 (A9 Pin)
	{
		HAL_NVIC_DisableIRQ(EXTI15_10_IRQn); // Disable EXTI interrupt
		Flash_LED2();
		HAL_NVIC_EnableIRQ(EXTI15_10_IRQn);  // Re-enable EXTI interrupt
	}
}
void Flash_LED2(void) {
	//HAL_NVIC_DisableIRQ(EXTI15_10_IRQn); // Disable EXTI interrupt
	for (int i = 0; i < 7; i++) {
		HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_SET);
		HAL_Delay(100);
		HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);
		HAL_Delay(100);
	}
	HAL_Delay(1500);
	//HAL_NVIC_EnableIRQ(EXTI15_10_IRQn); // Re-enable EXTI interrupt
}
/* USER CODE END 4 */

 What could be wrong as on pressing Blue button, LED2 is not flashing few times ?

[TDK · Accepted solution]

If you use HAL_Delay within an interrupt, you need to ensure systick has a higher (numerically lower) priority than the interrupt it's in.

It's generally better not to have blocking code within an interrupt. Instead, set a flag and handle it in the main loop.