STM32实现第一次按键控制LED的点亮，第二次按键LED熄灭的代码

好的，以下是基于STM32的按键控制LED点亮和熄灭的代码，注意这是一个简单的示例代码，需要根据具体的硬件和需求进行调整：

#include "stm32f10x.h"

GPIO_InitTypeDef GPIO_InitStructure;
NVIC_InitTypeDef NVIC_InitStructure;
EXTI_InitTypeDef EXTI_InitStructure;

int main(void)
{
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOC | RCC_APB2Periph_AFIO, ENABLE);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_13;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_Init(GPIOC, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

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

    EXTI_InitStructure.EXTI_Line = EXTI_Line0;
    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Falling;
    EXTI_InitStructure.EXTI_LineCmd = ENABLE;
    EXTI_Init(&EXTI_InitStructure);

    while(1)
    {
        //等待按键
    }
}

void EXTI0_IRQHandler(void)
{
    if(EXTI_GetITStatus(EXTI_Line0) != RESET)
    {
        static int flag = 0; //用于判断LED状态的标志位
        EXTI_ClearITPendingBit(EXTI_Line0); //清除中断标志位
        if(flag == 0)
        {
            GPIO_ResetBits(GPIOC, GPIO_Pin_13); //点亮LED
            flag = 1;
        }
        else
        {
            GPIO_SetBits(GPIOC, GPIO_Pin_13); //熄灭LED
            flag = 0;
        }
    }
}

这段代码实现的功能是：将PA0引脚配置为上拉输入，PC13引脚配置为推挽输出，按下按键PA0时，PC13的LED会从点亮状态变为熄灭状态，再按下按键PA0时，PC13的LED会从熄灭状态变为点亮状态。