Embedded System

Interrupt Driven STM32

PA11 as a Interrupt Source

Modify the code as following snippet, we will set PA11 as interrupt invoke.

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GPIO_InitStruct.Pin = GPIO_PIN_11;
GPIO_InitStruct.Mode = GPIO_MODE_IT_FALLING;
GPIO_InitStruct.Pull = GPIO_PULLUP;
GPIO_InitStruct.Speed = GPIO_SPEED_LOW;
HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

Handle the Interrupt

We must modify the code in interrupt handler.

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void EXTI15_10_IRQHandler(void){
	if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_11)!=0){
		HAL_GPIO_EXTI_IRQHandler(GPIO_PIN_11);
	}
	if (HAL_GPIO_ReadPin(GPIOA, GPIO_PIN_12)!=0){
		HAL_GPIO_EXTI_IRQHandler(GPIO_PIN_12);
	}
}

We need to recognize the interrupt source in the handler.

Callback

Hence, we could separate the GPIO_Pin in the callback function.

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void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin){
	switch (GPIO_Pin){
		case GPIO_PIN_11:
			printf("Pressed\r\n");
			mode=!mode;
			break;
		case GPIO_PIN_12:
			counter++;
			break;
	}
}

Enter the Sleep Mode

First, we must diable system tick interrupt. And then, the program must sleep again after the interrupt is handled.

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HAL_SuspendTick();
HAL_PWR_EnterSLEEPMode(PWR_MAINREGULATOR_ON, PWR_SLEEPENTRY_WFI);
HAL_PWR_EnableSleepOnExit();
while (1)
{
printf("CPU running!\r\n");
HAL_Delay(100);
}

Result


As you can see, the CPU running! in a dead loop only execute once. And other function run well.