最多只能有7个外部中断。

下面这个是GPIO口初始化。

void KEY_Init(void)

{

    GPIO_InitTypeDef  GPIO_InitStructure;

  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA|RCC_AHB1Periph_GPIOE, ENABLE);//使能GPIOA,GPIOE时钟

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_2|GPIO_Pin_3|GPIO_Pin_4; //KEY0 KEY1 KEY2对应引脚

  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;//普通输入模式

  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;//100M

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;//上拉

  GPIO_Init(GPIOE, &GPIO_InitStructure);//初始化GPIOE2,3,4

  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;//WK_UP对应引脚PA0

  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_DOWN ;//下拉

  GPIO_Init(GPIOA, &GPIO_InitStructure);//初始化GPIOA0

}

还有下图这一步，使能这个SYSCFG时钟，因为中断线用到了这个时钟

//外部中断初始化程序

//初始化PE2~4,PA0为中断输入.

void EXTIX_Init(void)

{

NVIC_InitTypeDef   NVIC_InitStructure;

EXTI_InitTypeDef   EXTI_InitStructure;

KEY_Init(); //按键对应的IO口初始化

RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);//使能SYSCFG时钟

SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOE, EXTI_PinSource2);//PE2 连接到中断线2

SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOE, EXTI_PinSource3);//PE3 连接到中断线3

SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOE, EXTI_PinSource4);//PE4 连接到中断线4

SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOA, EXTI_PinSource0);//PA0 连接到中断线0

  /* 配置EXTI_Line0 */

  EXTI_InitStructure.EXTI_Line = EXTI_Line0;//LINE0

  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;//中断事件

  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising; //上升沿触发  触发方式 

  EXTI_InitStructure.EXTI_LineCmd = ENABLE;//使能LINE0  

  EXTI_Init(&EXTI_InitStructure);//配置

/* 配置EXTI_Line2,3,4 */

EXTI_InitStructure.EXTI_Line = EXTI_Line2 | EXTI_Line3 | EXTI_Line4;

  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;//中断事件

  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling; //下降沿触发

  EXTI_InitStructure.EXTI_LineCmd = ENABLE;//中断线使能

  EXTI_Init(&EXTI_InitStructure);//配置

NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;//外部中断0

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x00;//抢占优先级0

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;//子优先级2

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;//使能外部中断通道

  NVIC_Init(&NVIC_InitStructure);//配置

NVIC_InitStructure.NVIC_IRQChannel = EXTI2_IRQn;//外部中断2

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x03;//抢占优先级3

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;//子优先级2

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;//使能外部中断通道

  NVIC_Init(&NVIC_InitStructure);//配置

NVIC_InitStructure.NVIC_IRQChannel = EXTI3_IRQn;//外部中断3

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x02;//抢占优先级2

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;//子优先级2

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;//使能外部中断通道

  NVIC_Init(&NVIC_InitStructure);//配置

NVIC_InitStructure.NVIC_IRQChannel = EXTI4_IRQn;//外部中断4

  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x01;//抢占优先级1

  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;//子优先级2

  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;//使能外部中断通道

  NVIC_Init(&NVIC_InitStructure);//配置

}

中断状态判断中断是否发生

外部中断只能手动清0  

下面回顾外部中断的配置步骤  如果我们的IO口是拉低的，那么可以配置成高电平触发。 这样我们的外部中断配置就完成了。

至此我们就完成外部中断实验的简单配置。