1 /* 2 * SPDX-FileCopyrightText: 2015-2022 Espressif Systems (Shanghai) CO LTD 3 * 4 * SPDX-License-Identifier: Apache-2.0 5 */ 6 7 #pragma once 8 9 #include <stdint.h> 10 #include "sdkconfig.h" 11 #include "esp_err.h" 12 #include "hal/adc_types.h" 13 #include "driver/adc_types_legacy.h" 14 #include "esp_adc_cal_types_legacy.h" 15 16 #if !CONFIG_ADC_SUPPRESS_DEPRECATE_WARN 17 #warning "legacy adc calibration driver is deprecated, please migrate to use esp_adc/adc_cali.h and esp_adc/adc_cali_scheme.h" 18 #endif 19 20 #ifdef __cplusplus 21 extern "C" { 22 #endif 23 24 #if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2 || CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32S3 25 /** 26 * @brief Checks if ADC calibration values are burned into eFuse 27 * 28 * This function checks if ADC reference voltage or Two Point values have been 29 * burned to the eFuse of the current ESP32 30 * 31 * @param value_type Type of calibration value (ESP_ADC_CAL_VAL_EFUSE_VREF or ESP_ADC_CAL_VAL_EFUSE_TP) 32 * @note in ESP32S2, only ESP_ADC_CAL_VAL_EFUSE_TP is supported. Some old ESP32S2s do not support this, either. 33 * In which case you have to calibrate it manually, possibly by performing your own two-point calibration on the chip. 34 * 35 * @return 36 * - ESP_OK: The calibration mode is supported in eFuse 37 * - ESP_ERR_NOT_SUPPORTED: Error, eFuse values are not burned 38 * - ESP_ERR_INVALID_ARG: Error, invalid argument (ESP_ADC_CAL_VAL_DEFAULT_VREF) 39 */ 40 esp_err_t esp_adc_cal_check_efuse(esp_adc_cal_value_t value_type); 41 42 /** 43 * @brief Characterize an ADC at a particular attenuation 44 * 45 * This function will characterize the ADC at a particular attenuation and generate 46 * the ADC-Voltage curve in the form of [y = coeff_a * x + coeff_b]. 47 * Characterization can be based on Two Point values, eFuse Vref, or default Vref 48 * and the calibration values will be prioritized in that order. 49 * 50 * @note 51 * For ESP32, Two Point values and eFuse Vref calibration can be enabled/disabled using menuconfig. 52 * For ESP32s2, only Two Point values calibration and only ADC_WIDTH_BIT_13 is supported. The parameter default_vref is unused. 53 * 54 * 55 * @param[in] adc_num ADC to characterize (ADC_UNIT_1 or ADC_UNIT_2) 56 * @param[in] atten Attenuation to characterize 57 * @param[in] bit_width Bit width configuration of ADC 58 * @param[in] default_vref Default ADC reference voltage in mV (Only in ESP32, used if eFuse values is not available) 59 * @param[out] chars Pointer to empty structure used to store ADC characteristics 60 * 61 * @return 62 * - ESP_ADC_CAL_VAL_EFUSE_VREF: eFuse Vref used for characterization 63 * - ESP_ADC_CAL_VAL_EFUSE_TP: Two Point value used for characterization (only in Linear Mode) 64 * - ESP_ADC_CAL_VAL_DEFAULT_VREF: Default Vref used for characterization 65 */ 66 esp_adc_cal_value_t esp_adc_cal_characterize(adc_unit_t adc_num, 67 adc_atten_t atten, 68 adc_bits_width_t bit_width, 69 uint32_t default_vref, 70 esp_adc_cal_characteristics_t *chars); 71 72 /** 73 * @brief Convert an ADC reading to voltage in mV 74 * 75 * This function converts an ADC reading to a voltage in mV based on the ADC's 76 * characteristics. 77 * 78 * @note Characteristics structure must be initialized before this function 79 * is called (call esp_adc_cal_characterize()) 80 * 81 * @param[in] adc_reading ADC reading 82 * @param[in] chars Pointer to initialized structure containing ADC characteristics 83 * 84 * @return Voltage in mV 85 */ 86 uint32_t esp_adc_cal_raw_to_voltage(uint32_t adc_reading, const esp_adc_cal_characteristics_t *chars); 87 88 /** 89 * @brief Reads an ADC and converts the reading to a voltage in mV 90 * 91 * This function reads an ADC then converts the raw reading to a voltage in mV 92 * based on the characteristics provided. The ADC that is read is also 93 * determined by the characteristics. 94 * 95 * @note The Characteristics structure must be initialized before this 96 * function is called (call esp_adc_cal_characterize()) 97 * 98 * @param[in] channel ADC Channel to read 99 * @param[in] chars Pointer to initialized ADC characteristics structure 100 * @param[out] voltage Pointer to store converted voltage 101 * 102 * @return 103 * - ESP_OK: ADC read and converted to mV 104 * - ESP_ERR_INVALID_ARG: Error due to invalid arguments 105 * - ESP_ERR_INVALID_STATE: Reading result is invalid. Try to read again. 106 */ 107 esp_err_t esp_adc_cal_get_voltage(adc_channel_t channel, const esp_adc_cal_characteristics_t *chars, uint32_t *voltage); 108 109 #endif //#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2 || CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32S3 110 111 #ifdef __cplusplus 112 } 113 #endif 114
