ESP32 idf 用gpio4做有个带校准的adc检测代码

以下是使用ESP32 IDF框架的GPIO4进行带校准的ADC检测代码示例：

#include <stdio.h>
#include "esp_system.h"
#include "driver/gpio.h"
#include "driver/adc.h"

#define DEFAULT_VREF    1100        //默认的参考电压值为1.1V
#define NO_OF_SAMPLES   64          //采样次数

void calibrate_voltage() {
    //配置ADC1的通道4，参考电压为1.1V
    adc1_config_channel_atten(ADC1_CHANNEL_4, ADC_ATTEN_DB_11);

    //计算出ADC1的读数的最大值和最小值
    int32_t voltage_min = 4096;
    int32_t voltage_max = 0;

    for (int i = 0; i < NO_OF_SAMPLES; i++) {
        int32_t voltage = adc1_get_raw(ADC1_CHANNEL_4);
        if (voltage < voltage_min) {
            voltage_min = voltage;
        }
        if (voltage > voltage_max) {
            voltage_max = voltage;
        }
        vTaskDelay(pdMS_TO_TICKS(50));
    }

    //计算出参考电压值
    float calibration_value = (float)(DEFAULT_VREF * NO_OF_SAMPLES) / (float)(voltage_max - voltage_min);

    printf("Calibration value: %f\n", calibration_value);
}

void read_voltage() {
    //配置ADC1的通道4，参考电压为1.1V
    adc1_config_channel_atten(ADC1_CHANNEL_4, ADC_ATTEN_DB_11);

    //读取ADC1的值，并根据校准值计算出实际电压值
    int32_t voltage_raw = 0;
    for (int i = 0; i < NO_OF_SAMPLES; i++) {
        voltage_raw += adc1_get_raw(ADC1_CHANNEL_4);
        vTaskDelay(pdMS_TO_TICKS(50));
    }

    float voltage = ((float)voltage_raw / (float)NO_OF_SAMPLES) * calibration_value;

    printf("Voltage: %f\n", voltage);
}

void app_main() {
    //配置GPIO4为输入模式
    gpio_pad_select_gpio(GPIO_NUM_4);
    gpio_set_direction(GPIO_NUM_4, GPIO_MODE_INPUT);

    calibrate_voltage();

    while (1) {
        if (gpio_get_level(GPIO_NUM_4) == 1) {
            read_voltage();
        }

        vTaskDelay(pdMS_TO_TICKS(50));
    }
}

该示例代码中的`calibrate_voltage()`函数用于校准ADC1通道4的读数，`read_voltage()`函数用于读取ADC1通道4的电压值。在`app_main()`函数中，首先将GPIO4配置为输入模式，然后循环检测GPIO4的状态，如果为高电平则读取电压值并打印。注意，在读取电压值之前需要先进行校准操作。