STM32F103ZET6 external interrupt

[Overview]

1. Each of IO STM32 can be used as external interrupt inputs.
2. STM32F1 interrupt controller supports 19 external interrupt / event request:
   Line 0 to 15: corresponding to the external IO port input interruption.
   Line 16: PVD is connected to the output.
   Line 17: Connect to the RTC alarm event.
   Line 18: Connect to the USB wake-up event.
3. Independently each external interrupt trigger arrangement (rising edge, falling edge or double edge triggered), the trigger / block, dedicated status bits.

[External interrupt Universal IO mapping broken]

GPIOx.0 mapped to EXTI0
GPIOx.1 mapped to EXTI1
...
GPIOx.15 mapped to EXTI15

[Interrupt service function]

EXTI0_IRQHandler () EXT line 0
EXTI1_IRQHandler () the EXTI line. 1
EXTI2_IRQHandler () the EXTI line 2
EXTI3_IRQHandler () the EXTI line. 3
EXTI4_IRQHandler () the EXTI line. 4
EXTI9_5_IRQHandler () the EXTI line 5-EXTI line. 9
EXTI15_10_IRQHandler () the EXTI line 10-EXTI line 15

[External interrupt configuration steps]

1. IO port initialization input.
   GPIO_Init ();
2. Open IO port multiplexing clock.
   RCC_APB2PeriphClockCmd (RCC_APB2Periph_AFIO, ENABLE);
3. The mapping between IO port and interrupt lines.
   void GPIO_EXTILineConfig ();
4. Initialization line break, set the trigger conditions.
   EXTI_Init ();
5. Configure interrupt packet (NVIC), and interrupts.
   NVIC_Init ();
6. Write interrupt service function.
   EXTIx_IRQHandler ();
7. Clear the interrupt flag
   EXTI_ClearITPendingBit ();

[External interrupt example code]

exti.c file

void EXTIX_Init(void)
{
	

	EXTI_InitTypeDef MyEXTIstruct;
	NVIC_InitTypeDef MyNVICstruct;
	
	KEY_Init();
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);   //使能复用功能
	
	GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource4);  //外部中断引脚选择
   
	MyEXTIstruct.EXTI_Line=EXTI_Line4; //配置中断线
	MyEXTIstruct.EXTI_LineCmd=ENABLE;   //使能
	MyEXTIstruct.EXTI_Mode=EXTI_Mode_Interrupt;  //中断
	MyEXTIstruct.EXTI_Trigger=EXTI_Trigger_Falling;  //下降沿触发
	EXTI_Init(&MyEXTIstruct);
	
	MyNVICstruct.NVIC_IRQChannel=EXTI4_IRQn;   //选择是哪个中断
	MyNVICstruct.NVIC_IRQChannelCmd=ENABLE;    //使能
	MyNVICstruct.NVIC_IRQChannelPreemptionPriority=2;  //配置抢占优先级
	MyNVICstruct.NVIC_IRQChannelSubPriority=2;   //配置响应优先级
	NVIC_Init(&MyNVICstruct);
	
}
 
void EXTI4_IRQHandler(void)
{
	delay_ms(10);  //由于是按键，消抖
	if(KEY0==0)
	{
		LED0=!LED0;
	  LED1=!LED1;
	}
	EXTI_ClearITPendingBit(EXTI_Line4);    //清空中断标志位
}

main.c file

 int main(void)
 {		
 
	delay_init();	    	 //延时函数初始化	  
	NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); //设置NVIC中断分组2:2位抢占优先级，2位响应优先级
	uart_init(115200);	 //串口初始化为115200
 	LED_Init();		  		//初始化与LED连接的硬件接口
	BEEP_Init();         	//初始化蜂鸣器端口
	KEY_Init();         	//初始化与按键连接的硬件接口
	EXTIX_Init();		 	//外部中断初始化
	LED0=0;					//点亮LED0
	while(1)
	{	    
		printf("OK\r\n");	
		delay_ms(1000);	  
	}
 }