将PB6设置为输入模式（当然你想用外部中断也行），用杜邦线将PB6分别于高低电平相接，若接高电平（3.3v），LED灯就亮，接低电平LED灯就灭

。以下是代码示例：

#include "stm32f10x.h"

void GPIO_Configuration(void);
void EXTI_Configuration(void);
void LED_On(void);
void LED_Off(void);

int main(void)
{
    GPIO_Configuration();
    EXTI_Configuration();

    while(1)
    {
        // do nothing
    }
}

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    // Enable GPIOB clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    // Configure PB6 as input floating
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOB, &GPIO_InitStructure);
}

void EXTI_Configuration(void)
{
    EXTI_InitTypeDef EXTI_InitStructure;
    NVIC_InitTypeDef NVIC_InitStructure;

    // Enable AFIO clock
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_AFIO, ENABLE);

    // Configure EXTI line 6
    GPIO_EXTILineConfig(GPIO_PortSourceGPIOB, GPIO_PinSource6);

    EXTI_InitStructure.EXTI_Line = EXTI_Line6;
    EXTI_InitStructure.EXTI_Mode = EXTI_Mode_Interrupt;
    EXTI_InitStructure.EXTI_Trigger = EXTI_Trigger_Rising_Falling;
    EXTI_InitStructure.EXTI_LineCmd = ENABLE;
    EXTI_Init(&EXTI_InitStructure);

    // Enable and set EXTI line 6 interrupt to the lowest priority
    NVIC_InitStructure.NVIC_IRQChannel = EXTI9_5_IRQn;
    NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0x0F;
    NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0x0F;
    NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
    NVIC_Init(&NVIC_InitStructure);
}

void EXTI9_5_IRQHandler(void)
{
    if(EXTI_GetITStatus(EXTI_Line6) != RESET)
    {
        // Check PB6 state
        if(GPIO_ReadInputDataBit(GPIOB, GPIO_Pin_6) == Bit_SET)
        {
            LED_On();
        }
        else
        {
            LED_Off();
        }

        // Clear interrupt flag
        EXTI_ClearITPendingBit(EXTI_Line6);
    }
}

void LED_On(void)
{
    GPIO_SetBits(GPIOC, GPIO_Pin_13);
}

void LED_Off(void)
{
    GPIO_ResetBits(GPIOC, GPIO_Pin_13);
}

注意，上述代码使用了外部中断，需要连接PB6到中断线，否则无法触发中断。如果只是简单的检测PB6的电平，可以不使用外部中断，直接轮询GPIO的状态即可。