STM32F103C8T6外部中断配置-PA0+PA1+PA2

    EXTI_InitTypeDef EXTI_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;
    GPIO_InitTypeDef GPIO_InitStructure; 
     
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);//打开GPIOA时钟
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);//外部中断，需要使能AFIO时钟

	 
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0|GPIO_Pin_1|GPIO_Pin_2;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
     
       GPIO_EXTILineConfig(GPIO_PortSourceGPIOA,GPIO_PinSource0);
       GPIO_EXTILineConfig(GPIO_PortSourceGPIOA,GPIO_PinSource1);
       GPIO_EXTILineConfig(GPIO_PortSourceGPIOA,GPIO_PinSource2);

    EXTI_DeInit();
  	EXTI_InitStructure.EXTI_Line=(EXTI_Line0|EXTI_Line1|EXTI_Line2);  //
  	EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;	
  	EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling; 
  	EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  	EXTI_Init(&EXTI_InitStructure);	 	 
        
    NVIC_InitStructure.NVIC_IRQChannel = (EXTI0_IRQChannel);  
  	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x1;	 
  	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;					 
  	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;								 
  	NVIC_Init(&NVIC_InitStructure);  	  

    NVIC_InitStructure.NVIC_IRQChannel = (EXTI1_IRQChannel);  
  	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x1;	 
  	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;					 
  	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;								 
  	NVIC_Init(&NVIC_InitStructure);  	  
  	
    NVIC_InitStructure.NVIC_IRQChannel = (EXTI2_IRQChannel);  
  	NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x1;	 
  	NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;					 
  	NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;								 
  	NVIC_Init(&NVIC_InitStructure);  	  

	    EXTI_ClearFlag(EXTI_Line0);
        EXTI_ClearFlag(EXTI_Line1);
        EXTI_ClearFlag(EXTI_Line2);