exti.c 文件代码如下： void EXTIX_Init(void) { NVIC_InitTypeDef NVIC_InitStructure; EXTI_InitTypeDef EXTI_InitStructure; RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE); SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOE, EXTI_PinSource0); EXTI_InitStructure.EXTI_Line = EXTI_Line0; EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt; EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising; //上升沿触发 EXTI_InitStructure.EXTI_LineCmd = ENABLE; EXTI_Init( &EXTI_InitStructure ); //中断 NVIC 配置 NVIC_InitStructure.NVIC_IRQChannel=EXTI0_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x00; NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02； NVIC_InitStructure.NVIC_IRQChannelCmd=ENABLE; NVIC_Init(&NVIC_InitStructure); } （3）编写 LED 与 KEY 相关代码。 （4）编写中断服务函数。 主函数代码如下： //包含相关头文件 int main(void) { NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2); delay_init(168); LED_Init(); KEY_Init(); EXTIX_Init(); LED0=0; while(1) { } } 4.4 实验练习 在实验 4.3 的框架中补齐代码，以 SW0（E0）做为外部中断输入引脚控制 LED 的亮灭。

LED 与 KEY 相关代码如下：

void LED_Init(void) {
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF, ENABLE);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOF, &GPIO_InitStructure);
}

void KEY_Init(void) {
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOE, &GPIO_InitStructure);
}

中断服务函数如下：

void EXTI0_IRQHandler(void) {
  if (EXTI_GetITStatus(EXTI_Line0) != RESET) {
    LED0 = !LED0;
    EXTI_ClearITPendingBit(EXTI_Line0);
  }
}

完整代码如下：

#include "stm32f4xx.h"
#include "delay.h"

#define LED0 PFout(9)
#define LED1 PFout(10)
#define KEY PEin(0)

void LED_Init(void) {
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOF, ENABLE);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9 | GPIO_Pin_10;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOF, &GPIO_InitStructure);
}

void KEY_Init(void) {
  GPIO_InitTypeDef GPIO_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);
  GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
  GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
  GPIO_Init(GPIOE, &GPIO_InitStructure);
}

void EXTIX_Init(void) {
  NVIC_InitTypeDef NVIC_InitStructure;
  EXTI_InitTypeDef EXTI_InitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
  SYSCFG_EXTILineConfig(EXTI_PortSourceGPIOE, EXTI_PinSource0);
  EXTI_InitStructure.EXTI_Line = EXTI_Line0;
  EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
  EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising; //上升沿触发
  EXTI_InitStructure.EXTI_LineCmd = ENABLE;
  EXTI_Init( &EXTI_InitStructure ); //中断 EXTI 配置
  NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
  NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x00;
  NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x02;
  NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
  NVIC_Init(&NVIC_InitStructure); //中断 NVIC 配置
}

int main(void) {
  NVIC_PriorityGroupConfig(NVIC_PriorityGroup_2);
  delay_init(168);
  LED_Init();
  KEY_Init();
  EXTIX_Init();
  LED0 = 0;
  while(1) {
  }
}

void EXTI0_IRQHandler(void) {
  if (EXTI_GetITStatus(EXTI_Line0) != RESET) {
    LED0 = !LED0;
    EXTI_ClearITPendingBit(EXTI_Line0);
  }
}