ESP-IDF
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Outline
#include <stdint.h>
#include "sdkconfig.h"
#include "esp_err.h"
#include "hal/adc_types.h"
#include "driver/adc_types_legacy.h"
#include "esp_adc_cal_types_legacy.h"
esp_adc_cal_check_efuse(esp_adc_cal_value_t);
esp_adc_cal_characterize(adc_unit_t, adc_atten_t, adc_bits_width_t, uint32_t, esp_adc_cal_characteristics_t *);
esp_adc_cal_raw_to_voltage(uint32_t, const esp_adc_cal_characteristics_t *);
esp_adc_cal_get_voltage(adc_channel_t, const esp_adc_cal_characteristics_t *, uint32_t *);
Files
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SourceVuESP-IDF Framework and ExamplesESP-IDFcomponents/esp_adc/deprecated/include/esp_adc_cal.h
 
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/* * SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD * * SPDX-License-Identifier: Apache-2.0 *//* ... */ #pragma once #include <stdint.h> #include "sdkconfig.h" #include "esp_err.h" #include "hal/adc_types.h" #include "driver/adc_types_legacy.h" #include "esp_adc_cal_types_legacy.h"6 includes #if !CONFIG_ADC_SUPPRESS_DEPRECATE_WARN #warning "legacy adc calibration driver is deprecated, please migrate to use esp_adc/adc_cali.h and esp_adc/adc_cali_scheme.h" #endif #ifdef __cplusplus extern "C" { #endif #if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2 || CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32S3 /** * @brief Checks if ADC calibration values are burned into eFuse * * This function checks if ADC reference voltage or Two Point values have been * burned to the eFuse of the current ESP32 * * @param value_type Type of calibration value (ESP_ADC_CAL_VAL_EFUSE_VREF or ESP_ADC_CAL_VAL_EFUSE_TP) * @note in ESP32S2, only ESP_ADC_CAL_VAL_EFUSE_TP is supported. Some old ESP32S2s do not support this, either. * In which case you have to calibrate it manually, possibly by performing your own two-point calibration on the chip. * * @return * - ESP_OK: The calibration mode is supported in eFuse * - ESP_ERR_NOT_SUPPORTED: Error, eFuse values are not burned * - ESP_ERR_INVALID_ARG: Error, invalid argument (ESP_ADC_CAL_VAL_DEFAULT_VREF) *//* ... */ esp_err_t esp_adc_cal_check_efuse(esp_adc_cal_value_t value_type); /** * @brief Characterize an ADC at a particular attenuation * * This function will characterize the ADC at a particular attenuation and generate * the ADC-Voltage curve in the form of [y = coeff_a * x + coeff_b]. * Characterization can be based on Two Point values, eFuse Vref, or default Vref * and the calibration values will be prioritized in that order. * * @note * For ESP32, Two Point values and eFuse Vref calibration can be enabled/disabled using menuconfig. * For ESP32s2, only Two Point values calibration and only ADC_WIDTH_BIT_13 is supported. The parameter default_vref is unused. * * * @param[in] adc_num ADC to characterize (ADC_UNIT_1 or ADC_UNIT_2) * @param[in] atten Attenuation to characterize * @param[in] bit_width Bit width configuration of ADC * @param[in] default_vref Default ADC reference voltage in mV (Only in ESP32, used if eFuse values is not available) * @param[out] chars Pointer to empty structure used to store ADC characteristics * * @return * - ESP_ADC_CAL_VAL_EFUSE_VREF: eFuse Vref used for characterization * - ESP_ADC_CAL_VAL_EFUSE_TP: Two Point value used for characterization (only in Linear Mode) * - ESP_ADC_CAL_VAL_DEFAULT_VREF: Default Vref used for characterization *//* ... */ esp_adc_cal_value_t esp_adc_cal_characterize(adc_unit_t adc_num, adc_atten_t atten, adc_bits_width_t bit_width, uint32_t default_vref, esp_adc_cal_characteristics_t *chars); /** * @brief Convert an ADC reading to voltage in mV * * This function converts an ADC reading to a voltage in mV based on the ADC's * characteristics. * * @note Characteristics structure must be initialized before this function * is called (call esp_adc_cal_characterize()) * * @param[in] adc_reading ADC reading * @param[in] chars Pointer to initialized structure containing ADC characteristics * * @return Voltage in mV *//* ... */ uint32_t esp_adc_cal_raw_to_voltage(uint32_t adc_reading, const esp_adc_cal_characteristics_t *chars); /** * @brief Reads an ADC and converts the reading to a voltage in mV * * This function reads an ADC then converts the raw reading to a voltage in mV * based on the characteristics provided. The ADC that is read is also * determined by the characteristics. * * @note The Characteristics structure must be initialized before this * function is called (call esp_adc_cal_characterize()) * * @param[in] channel ADC Channel to read * @param[in] chars Pointer to initialized ADC characteristics structure * @param[out] voltage Pointer to store converted voltage * * @return * - ESP_OK: ADC read and converted to mV * - ESP_ERR_INVALID_ARG: Error due to invalid arguments * - ESP_ERR_INVALID_STATE: Reading result is invalid. Try to read again. *//* ... */ esp_err_t esp_adc_cal_get_voltage(adc_channel_t channel, const esp_adc_cal_characteristics_t *chars, uint32_t *voltage); /* ... */ #endif //#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2 || CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32S3 #ifdef __cplusplus }{...} #endif
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