用STM32F407使用外部中断按键控制LED亮灭

首先，需要将按键接到STM32F407的外部中断输入引脚上。假设按键连接到了GPIOE的第0位引脚。

接下来，需要进行如下配置：

1. 使能GPIOE时钟

RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);

2. 配置GPIOE.0为输入模式

GPIO_InitTypeDef GPIO_InitStructure;
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_Init(GPIOE, &GPIO_InitStructure);

3. 配置外部中断 EXTI0

EXTI_InitTypeDef EXTI_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;

GPIO_EXTILineConfig(GPIO_PortSourceGPIOE, GPIO_PinSource0);
EXTI_InitStructure.EXTI_Line = EXTI_Line0;
EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
EXTI_InitStructure.EXTI_LineCmd = ENABLE;
EXTI_Init(&EXTI_InitStructure);

NVIC_InitStructure.NVIC_IRQChannel = EXTI0_IRQn;
NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x00;
NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x01;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_Init(&NVIC_InitStructure);

4. 在EXTI0_IRQHandler中实现按键控制LED亮灭

void EXTI0_IRQHandler(void)
{
  if(EXTI_GetITStatus(EXTI_Line0) != RESET)
  {
    // 读取按键状态，如果按键按下，则点亮LED
    if(GPIO_ReadInputDataBit(GPIOE, GPIO_Pin_0) == Bit_RESET)
    {
      GPIO_SetBits(GPIOA, GPIO_Pin_5);
    }
    // 否则熄灭LED
    else
    {
      GPIO_ResetBits(GPIOA, GPIO_Pin_5);
    }

    EXTI_ClearITPendingBit(EXTI_Line0);
  }
}

在上述代码中，我们假设将LED连接到了GPIOA的第5位引脚上。在按下按键时，点亮LED；松开按键时，熄灭LED。