① 初始化IO口為輸入。

       GPIO_Init();

② 開啟IO口複用時鐘。

       RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);

③ 設定IO口與中斷線的對映關係。

        void GPIO_EXTILineConfig();

④ 初始化線上中斷，設定觸發條件等。

       EXTI_Init();

⑤ 配置中斷分組（NVIC），並使能中斷。

       NVIC_Init();

⑥ 編寫中斷服務函式。

      EXTIx_IRQHandler();

⑦ 清除中斷標誌位

      EXTI_ClearITPendingBit();

原始碼：

 1 void EXTIX_Init(void)
 2 {
 3        EXTI_InitTypeDef EXTI_InitStructure;
 4      NVIC_InitTypeDef NVIC_InitStructure;
 5 
 6     KEY_Init();     //    °´¼ü¶Ë¿Ú³õʼ»¯
 7 
 8       RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO,ENABLE);    
 9 
10    //GPIOE.3      ÖжÏÏßÒÔ¼°Öжϳõʼ»¯ÅäÖà ϽµÑØ´¥·¢ 
 
//KEY1
11       GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource3);
12       EXTI_InitStructure.EXTI_Line=EXTI_Line3;
13       EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;    
14       EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
15       EXTI_Init(&EXTI_InitStructure);          //¸ù¾ÝEXTI_InitStructÖÐÖ¸¶¨µÄ²ÎÊý³õʼ»¯ÍâÉèEXTI¼Ä´æÆ÷
16 
17    //GPIOE.4      ÖжÏÏßÒÔ¼°Öжϳõʼ»¯ÅäÖà  Ï½µÑØ´¥·¢    //KEY0
18       GPIO_EXTILineConfig(GPIO_PortSourceGPIOE,GPIO_PinSource4);
19       EXTI_InitStructure.EXTI_Line=EXTI_Line4;
20       EXTI_Init(&EXTI_InitStructure);          //¸ù¾ÝEXTI_InitStructÖÐÖ¸¶¨µÄ²ÎÊý³õʼ»¯ÍâÉèEXTI¼Ä´æÆ÷
21 
22 
23    //GPIOA.0      ÖжÏÏßÒÔ¼°Öжϳõʼ»¯ÅäÖà ÉÏÉýÑØ´¥·¢ PA0  WK_UP
24      GPIO_EXTILineConfig(GPIO_PortSourceGPIOA,GPIO_PinSource0); 
25 
26       EXTI_InitStructure.EXTI_Line=EXTI_Line0;
27       EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising;
28       EXTI_Init(&EXTI_InitStructure);        //¸ù¾ÝEXTI_InitStructÖÐÖ¸¶¨µÄ²ÎÊý³õʼ»¯ÍâÉèEXTI¼Ä´æÆ÷
29 
30 
31       NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;            //ʹÄÜ°´¼üWK_UPËùÔÚµÄÍⲿÖжÏͨµÀ
32       NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;    //ÇÀÕ¼ÓÅÏȼ¶2£¬ 
33       NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x03;                    //×ÓÓÅÏȼ¶3
34       NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;                                //ʹÄÜÍⲿÖжÏͨµÀ
35       NVIC_Init(&NVIC_InitStructure); 
36 
37       NVIC_InitStructure.NVIC_IRQChannel = EXTI3_IRQn;            //ʹÄÜ°´¼üKEY1ËùÔÚµÄÍⲿÖжÏͨµÀ
38       NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;    //ÇÀÕ¼ÓÅÏȼ¶2 
39       NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;                    //×ÓÓÅÏȼ¶1 
40       NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;                                //ʹÄÜÍⲿÖжÏͨµÀ
41       NVIC_Init(&NVIC_InitStructure);        //¸ù¾ÝNVIC_InitStructÖÐÖ¸¶¨µÄ²ÎÊý³õʼ»¯ÍâÉèNVIC¼Ä´æÆ÷
42 
43       NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn;            //ʹÄÜ°´¼üKEY0ËùÔÚµÄÍⲿÖжÏͨµÀ
44       NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;    //ÇÀÕ¼ÓÅÏȼ¶2 
45       NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x00;                    //×ÓÓÅÏȼ¶0 
46       NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;                                //ʹÄÜÍⲿÖжÏͨµÀ
47       NVIC_Init(&NVIC_InitStructure);        //¸ù¾ÝNVIC_InitStructÖÐÖ¸¶¨µÄ²ÎÊý³õʼ»¯ÍâÉèNVIC¼Ä´æÆ÷
48  
49 }
50 
51 //ÍⲿÖжÏ0·þÎñ³ÌÐò 
52 void EXTI0_IRQHandler(void)
53 {
54     delay_ms(10);//Ïû¶¶
55     if(WK_UP==1)          //WK_UP°´¼ü
56     {                 
57         BEEP=!BEEP;    
58     }
59     EXTI_ClearITPendingBit(EXTI_Line0); //Çå³ýLINE0ÉϵÄÖжϱê־λ  
60 }
61  
62 
63 //ÍⲿÖжÏ3·þÎñ³ÌÐò
64 void EXTI3_IRQHandler(void)
65 {
66     delay_ms(10);//Ïû¶¶
67     if(KEY1==0)     //°´¼üKEY1
68     {                 
69         LED1=!LED1;
70     }         
71     EXTI_ClearITPendingBit(EXTI_Line3);  //Çå³ýLINE3ÉϵÄÖжϱê־λ  
72 }
73 
74 void EXTI4_IRQHandler(void)
75 {
76     delay_ms(10);//Ïû¶¶
77     if(KEY0==0)     //°´¼üKEY0
78     {
79         LED0=!LED0;
80         LED1=!LED1; 
81     }         
82     EXTI_ClearITPendingBit(EXTI_Line4);  //Çå³ýLINE4ÉϵÄÖжϱê־λ  
83 }