STM - exti external interrupt learning notes

One 、 Introduction to external interrupts ：

STM32 Of Every IO Can be used as an external interrupt Interrupt input port of , This is also true. STM32 The power of .STM32F103 The interrupt controller supports 19 External interrupts / Event request . Each interrupt is provided with a status bit , Every interrupt / Events have independent trigger and mask settings .

STM32F103 Of 19 An external interrupt is ： Line 0~15： Corresponding to the outside IO The input of the port is interrupted ;

                                                         Line 16： Connect to PVD Output ;

                                                         Line 17： Connect to RTC Alarm clock event ;

                                                         Line 18： Connect to USB Wake Events ;

Two 、 Corresponding to interrupt channel IO mouth

GPIO Discipline GPIOx.0~GPIOx.15(x=A,B,C,D,E,F,G) Corresponding to the interrupt line respectively 0~15

 

3、 ... and 、 Mapping relationship of interrupt function

That is to say, for the break line (A、B、C、D、E、F)0~4, Each interrupt line corresponds to a separate interrupt function

trunk (A、B、C、D、E、F)5~9, Corresponding interrupt function EXTI9_5_IRQHander

trunk (A、B、C、D、E、F)10~15, Corresponding interrupt function EXTI15_10_IRQHander

It may not be easy to understand , for instance , I'm using PB12、PB13、PB14、PB15, These three IO When the port generates an interrupt, it will enter the interrupt function EXTI15_10_IRQHander in , Then determine the specific one inside the interrupt function IO Interrupt caused by port .

 

Four 、 Configuration process of external interruption

1、 First, configure those that need to use external interrupts IO mouth

example ：KEY0→PB12        KEY1→PB13        KEY2→PB14        KEY3→PB15

void KEY_Init(void) //IO initialization 
{ 
 	GPIO_InitTypeDef GPIO_InitStructure;
 
 	RCC_APB2PeriphClockCmd(KEY1_GPIO_CLK,ENABLE);// Can make PORTB  The clock 
	
	GPIO_InitStructure.GPIO_Pin  = KEY0_GPIO_PIN | KEY1_GPIO_PIN | KEY2_GPIO_PIN | KEY3_GPIO_PIN;//KEY0-4
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; 		// Set as pull-up input 
 	GPIO_Init(KEY1_GPIO_PORT, &GPIO_InitStructure);				// initialization GPIO

}

2、 Configure the corresponding interrupt line And Interrupt channel setting

    GPIO_EXTILineConfig(GPIO_PortSourceGPIOB,GPIO_PinSource12);
  	EXTI_InitStructure.EXTI_Line=EXTI_Line12;											//PB12   Corresponding   EXTI_Line12
  	EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;	     			//( Select interrupt   still   event ) The interrupt 
  	EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;  			// Falling edge trigger 
  	EXTI_Init(&EXTI_InitStructure);	  	

   //GPIOB.13	   Interrupt line and interrupt initialization configuration    Falling edge trigger 	//KEY1
  	GPIO_EXTILineConfig(GPIO_PortSourceGPIOB,GPIO_PinSource13);
  	EXTI_InitStructure.EXTI_Line=EXTI_Line13;
  	EXTI_Init(&EXTI_InitStructure);	  	// according to EXTI_InitStruct The parameter specified in EXTI register 


   //GPIOB.14	   Interrupt line and interrupt initialization configuration   Falling edge trigger   //KEY2
 	GPIO_EXTILineConfig(GPIO_PortSourceGPIOB,GPIO_PinSource14); 
  	EXTI_InitStructure.EXTI_Line=EXTI_Line14;
  	EXTI_Init(&EXTI_InitStructure);		// according to EXTI_InitStruct The parameter specified in EXTI register 

   //GPIOB.14	   Interrupt line and interrupt initialization configuration   Falling edge trigger   //KEY3
 	GPIO_EXTILineConfig(GPIO_PortSourceGPIOB,GPIO_PinSource15); 
  	EXTI_InitStructure.EXTI_Line=EXTI_Line15;
  	EXTI_Init(&EXTI_InitStructure);		// according to EXTI_InitStruct The parameter specified in EXTI register 

    NVIC_InitStructure.NVIC_IRQChannel = EXTI15_10_IRQn;			// Enable key WK_UP External interrupt channel 
  	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x00;	// preemption 2, 
  	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x00;					// Sub priority 3
  	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;								// Enable external interrupt channels 
  	NVIC_Init(&NVIC_InitStructure); 

  Four 、 Interrupt function ：

void EXTI15_10_IRQHandler(void)
{
	if(KEY0 == 0)
	{
		exti_flag=1;
		EXTI_ClearITPendingBit(EXTI_Line12); // eliminate LINE0 Interrupt flag bit on   
		while(KEY0==0);
	}
	if(KEY1 == 0)
	{
		exti_flag=2;
		EXTI_ClearITPendingBit(EXTI_Line13); // eliminate LINE0 Interrupt flag bit on   
		while(KEY1==0);
	}
	if(KEY2 == 0)
	{
		exti_flag=3;
		EXTI_ClearITPendingBit(EXTI_Line14); // eliminate LINE0 Interrupt flag bit on   
		while(KEY2==0);
	}
	if(KEY3 == 0)
	{
		exti_flag=4;
		EXTI_ClearITPendingBit(EXTI_Line15); // eliminate LINE0 Interrupt flag bit on   
		while(KEY3==0);
	}
	
}