写一个stm32f103rc6使用MQ2获得烟雾浓度的代码

以下是一个简单的示例代码，用于使用STM32F103RC6和MQ2传感器获取烟雾浓度：

#include "stm32f10x.h"

#define MQ2_ADC_CHANNEL 0
#define MQ2_RL_VALUE 10
#define MQ2_RO_CLEAN_AIR_FACTOR 9.83

void ADC1_Init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure;
    ADC_InitTypeDef ADC_InitStructure;

    /* Enable ADC1 and GPIOA clock */
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1 | RCC_APB2Periph_GPIOA, ENABLE);

    /* Configure ADC1 Channel0 pin as analog input */
    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_0;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AIN;
    GPIO_Init(GPIOA, &GPIO_InitStructure);

    /* ADC1 configuration */
    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);

    /* ADC1 regular channel0 configuration */
    ADC_RegularChannelConfig(ADC1, MQ2_ADC_CHANNEL, 1, ADC_SampleTime_55Cycles5);

    /* Enable ADC1 */
    ADC_Cmd(ADC1, ENABLE);
}

uint16_t MQ2_Read(void)
{
    uint32_t sum = 0;
    uint16_t i;
    uint16_t buffer[10];

    /* Read multiple samples */
    for (i = 0; i < 10; i++)
    {
        /* Start the conversion */
        ADC_SoftwareStartConvCmd(ADC1, ENABLE);

        /* Wait for the conversion to complete */
        while (ADC_GetFlagStatus(ADC1, ADC_FLAG_EOC) == RESET);

        /* Read the converted value */
        buffer[i] = ADC_GetConversionValue(ADC1);

        /* Add the converted value to the sum */
        sum += buffer[i];
    }

    /* Calculate the average value */
    uint16_t average = sum / 10;

    /* Calculate the resistance of the sensor */
    float resistance = ((float)(4095 - average) * MQ2_RL_VALUE) / average;

    /* Calculate the sensor resistance ratio */
    float ratio = resistance / MQ2_RO_CLEAN_AIR_FACTOR;

    /* Calculate the gas concentration in ppm */
    float concentration = 10 * pow(3.43, -3) * pow(ratio, -1.27);

    /* Convert the concentration to an integer value */
    uint16_t ppm = (uint16_t)concentration;

    return ppm;
}

int main(void)
{
    ADC1_Init();

    while (1)
    {
        uint16_t ppm = MQ2_Read();

        /* Do something with the ppm value */
    }
}

在这个示例代码中，我们首先初始化了ADC1，然后定义了一个`MQ2_Read()`函数来读取MQ2传感器的值。该函数首先通过ADC读取传感器的电压值，然后计算出传感器的电阻值和浓度值，并将浓度值返回给主函数。在主函数中，我们可以使用返回的浓度值来执行任何适当的操作。请注意，示例代码中的计算公式可能需要根据您使用的MQ2传感器进行调整。