用stm32f103c8t6实现mq2烟雾报警，并用串口输出的代码

好的，以下是用STM32F103C8T6实现MQ2烟雾报警并用串口输出的代码，供参考：

#include "stm32f10x.h"
#include "stdio.h"

#define MQ2_PIN GPIO_Pin_0
#define MQ2_PORT GPIOA

void GPIO_Configuration(void);
void USART_Configuration(void);
void USART_SendChar(char c);

int main(void)
{
    uint16_t adc_value;
    char buffer[10];

    GPIO_Configuration();
    USART_Configuration();

    while(1)
    {
        GPIO_SetBits(MQ2_PORT, MQ2_PIN);  // 开启MQ2传感器
        ADC_SoftwareStartConvCmd(ADC1, ENABLE);  // 启动ADC转换
        while(!ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC));  // 等待转换完成
        adc_value = ADC_GetConversionValue(ADC1);  // 读取ADC值
        GPIO_ResetBits(MQ2_PORT, MQ2_PIN);  // 关闭MQ2传感器

        if(adc_value > 1000)  // 判断MQ2传感器是否检测到烟雾
        {
            sprintf(buffer, "%d", adc_value);  // 将ADC值转换为字符串
            USART_SendChar('S');  // 发送烟雾报警信号
            USART_SendChar(buffer[0]);  // 发送ADC值的第一位数字
            USART_SendChar(buffer[1]);  // 发送ADC值的第二位数字
            USART_SendChar(buffer[2]);  // 发送ADC值的第三位数字
            USART_SendChar('\n');  // 发送换行符
        }

        delay_ms(1000);  // 延时1秒钟
    }
}

void GPIO_Configuration(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA | RCC_APB2Periph_ADC1 | RCC_APB2Periph_AFIO, ENABLE);

    GPIO_InitStructure.GPIO_Pin = MQ2_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(MQ2_PORT, &GPIO_InitStructure);

    ADC_InitTypeDef ADC_InitStructure;
    ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
    ADC_InitStructure.ADC_ScanConvMode = DISABLE;
    ADC_InitStructure.ADC_ContinuousConvMode = DISABLE;
    ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
    ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
    ADC_InitStructure.ADC_NbrOfChannel = 1;
    ADC_Init(ADC1, &ADC_InitStructure);

    ADC_Cmd(ADC1, ENABLE);

    ADC_RegularChannelConfig(ADC1, ADC_Channel_0, 1, ADC_SampleTime_239Cycles5);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(GPIOA, &GPIO_InitStructure);
}

void USART_Configuration(void)
{
    USART_InitTypeDef USART_InitStructure;

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_USART1, ENABLE);

    USART_InitStructure.USART_BaudRate = 9600;
    USART_InitStructure.USART_WordLength = USART_WordLength_8b;
    USART_InitStructure.USART_StopBits = USART_StopBits_1;
    USART_InitStructure.USART_Parity = USART_Parity_No;
    USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
    USART_InitStructure.USART_Mode = USART_Mode_Tx;
    USART_Init(USART1, &USART_InitStructure);

    USART_Cmd(USART1, ENABLE);
}

void USART_SendChar(char c)
{
    while(USART_GetFlagStatus(USART1, USART_FLAG_TXE) == RESET);
    USART_SendData(USART1, c);
}

void delay_ms(uint16_t ms)
{
    volatile uint32_t nCount;
    RCC_ClocksTypeDef RCC_Clocks;
    RCC_GetClocksFreq(&RCC_Clocks);
    nCount = (RCC_Clocks.HCLK_Frequency / 10000) * ms;
    for(; nCount != 0; nCount--);
}

注意：以上代码仅供参考，需要根据具体的硬件环境和需求进行适当修改。