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具体配置代码

void EXTIX_Init(void)
{
	//step1.初始化IO口
	GPIO_InitTypeDef GPIO_InitStructure;
 	RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOE,ENABLE);//使能PORTE时钟
	GPIO_InitStructure.GPIO_Pin  = GPIO_Pin_4;//KEY
	GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU; //设置成上拉输入
 	GPIO_Init(GPIOE, &GPIO_InitStructure);//初始化GPIOE4
	
	
	//step2.开启IO复用时钟
	RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);	//使能复用功能时钟
	
	//step3.配置中断线
	GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource4);//PE4映射到了中断线4
	
	//step4.初始化中断线
	EXTI_InitTypeDef EXTI_InitStructure;
	EXTI_InitStructure.EXTI_Line=EXTI_Line4;
	EXTI_InitStructure.EXTI_LineCmd=ENABLE;
	EXTI_InitStructure.EXTI_Mode=EXTI_Mode_Interrupt;
	EXTI_InitStructure.EXTI_Trigger=EXTI_Trigger_Falling;
	EXTI_Init(&EXTI_InitStructure);
	
	//step5.配置并且使能中断
	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
	NVIC_InitTypeDef NVIC_InitStructure;
	NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn;			//使能按键KEY所在的外部中断通道
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;	//抢占优先级2 
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x00;					//子优先级0 
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;								//使能外部中断通道
    NVIC_Init(&NVIC_InitStructure);  	  //根据NVIC_InitStruct中指定的参数初始化外设NVIC寄存器
}

//step6.编写中断服务函数
void EXTI4_IRQHandler(void)
{
	{
		//....
	}
	
	//step7.清除终端标志位
	EXTI_ClearITPendingBit(EXTI_Line4);  //清除LINE4上的中断标志位  
}