mirror of
https://github.com/espressif/esp-idf.git
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233 lines
9.0 KiB
C
233 lines
9.0 KiB
C
/*
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* SPDX-FileCopyrightText: 2019-2023 Espressif Systems (Shanghai) CO LTD
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <stdint.h>
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#include <stdbool.h>
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#include <string.h>
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#include "esp_types.h"
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#include "esp_err.h"
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#include "esp_log.h"
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#include "esp_check.h"
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#include "esp_heap_caps.h"
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#include "soc/soc_caps.h"
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#include "esp_adc/adc_cali_scheme.h"
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#include "adc_cali_interface.h"
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#include "esp_private/adc_share_hw_ctrl.h"
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#if ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED
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#include "esp_efuse_rtc_calib.h"
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#include "curve_fitting_coefficients.h"
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const __attribute__((unused)) static char *TAG = "adc_cali";
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// coeff_a is actually a float number
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// it is scaled to put them into uint32_t so that the headers do not have to be changed
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static const int coeff_a_scaling = 65536;
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/* -------------------- Characterization Helper Data Types ------------------ */
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typedef struct {
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uint32_t voltage;
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uint32_t digi;
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} adc_calib_data_ver1_t;
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typedef struct {
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char version_num;
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adc_unit_t unit_id;
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adc_atten_t atten;
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union {
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adc_calib_data_ver1_t ver1;
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} ref_data;
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} adc_calib_info_t;
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/* ------------------------ Context Structure--------------------------- */
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typedef struct {
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uint32_t coeff_a; ///< Gradient of ADC-Voltage curve
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uint32_t coeff_b; ///< Offset of ADC-Voltage curve
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} cali_chars_first_step_t;
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typedef struct {
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adc_unit_t unit_id; ///< ADC unit
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adc_channel_t chan; ///< ADC channel
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adc_atten_t atten; ///< ADC attenuation
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cali_chars_first_step_t chars_first_step; ///< Calibration first step characteristics
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cali_chars_second_step_t chars_second_step; ///< Calibration second step characteristics
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} cali_chars_curve_fitting_t;
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/* ----------------------- Characterization Functions ----------------------- */
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static void get_first_step_reference_point(int version_num, adc_unit_t unit_id, adc_atten_t atten, adc_calib_info_t *calib_info);
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static void calc_first_step_coefficients(const adc_calib_info_t *parsed_data, cali_chars_curve_fitting_t *chars);
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static int32_t get_reading_error(uint64_t v_cali_1, const cali_chars_second_step_t *param);
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static esp_err_t check_valid(const adc_cali_curve_fitting_config_t *config);
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/* ------------------------ Interface Functions --------------------------- */
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static esp_err_t cali_raw_to_voltage(void *arg, int raw, int *voltage);
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/* ------------------------- Public API ------------------------------------- */
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esp_err_t adc_cali_create_scheme_curve_fitting(const adc_cali_curve_fitting_config_t *config, adc_cali_handle_t *ret_handle)
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{
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esp_err_t ret = ESP_OK;
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ESP_RETURN_ON_FALSE(config && ret_handle, ESP_ERR_INVALID_ARG, TAG, "invalid arg: null pointer");
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ret = check_valid(config);
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if (ret != ESP_OK) {
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return ret;
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}
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// current version only accepts encoding version: ESP_EFUSE_ADC_CALIB_VER_MIN <= adc_encoding_version <= ESP_EFUSE_ADC_CALIB_VER_MAX.
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uint32_t adc_encoding_version = esp_efuse_rtc_calib_get_ver();
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ESP_RETURN_ON_FALSE((adc_encoding_version >= ESP_EFUSE_ADC_CALIB_VER_MIN) &&
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(adc_encoding_version <= ESP_EFUSE_ADC_CALIB_VER_MAX), ESP_ERR_NOT_SUPPORTED, TAG, "Calibration required eFuse bits not burnt");
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adc_cali_scheme_t *scheme = (adc_cali_scheme_t *)heap_caps_calloc(1, sizeof(adc_cali_scheme_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
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ESP_RETURN_ON_FALSE(scheme, ESP_ERR_NO_MEM, TAG, "no mem for adc calibration scheme");
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cali_chars_curve_fitting_t *chars = (cali_chars_curve_fitting_t *)heap_caps_calloc(1, sizeof(cali_chars_curve_fitting_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT);
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ESP_GOTO_ON_FALSE(chars, ESP_ERR_NO_MEM, err, TAG, "no memory for the calibration characteristics");
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scheme->raw_to_voltage = cali_raw_to_voltage;
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scheme->ctx = chars;
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//Prepare calibration characteristics
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adc_calib_info_t calib_info = {0};
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//Set first step calibration context
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get_first_step_reference_point(adc_encoding_version, config->unit_id, config->atten, &calib_info);
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calc_first_step_coefficients(&calib_info, chars);
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//Set second step calibration context
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curve_fitting_get_second_step_coeff(config, &(chars->chars_second_step));
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chars->unit_id = config->unit_id;
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chars->chan = config->chan;
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chars->atten = config->atten;
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*ret_handle = scheme;
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return ESP_OK;
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err:
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if (scheme) {
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free(scheme);
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}
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return ret;
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}
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esp_err_t adc_cali_delete_scheme_curve_fitting(adc_cali_handle_t handle)
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{
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ESP_RETURN_ON_FALSE(handle, ESP_ERR_INVALID_ARG, TAG, "invalid argument: null pointer");
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free(handle->ctx);
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handle->ctx = NULL;
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free(handle);
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handle = NULL;
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return ESP_OK;
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}
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/* ------------------------ Interface Functions --------------------------- */
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static esp_err_t cali_raw_to_voltage(void *arg, int raw, int *voltage)
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{
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//pointers are checked in the upper layer
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cali_chars_curve_fitting_t *ctx = arg;
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#if SOC_ADC_CALIB_CHAN_COMPENS_SUPPORTED
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int chan_compensation = adc_get_hw_calibration_chan_compens(ctx->unit_id, ctx->chan, ctx->atten);
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raw -= chan_compensation;
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/* Limit the range */
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int max_val = (1L << SOC_ADC_RTC_MAX_BITWIDTH) - 1;
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raw = raw <= 0 ? 0 :
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raw > max_val ? max_val : raw;
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#endif // SOC_ADC_CALIB_CHAN_COMPENS_SUPPORTED
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uint64_t v_cali_1 = (uint64_t)raw * ctx->chars_first_step.coeff_a / coeff_a_scaling + ctx->chars_first_step.coeff_b;
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int32_t error = get_reading_error(v_cali_1, &(ctx->chars_second_step));
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*voltage = (int32_t)v_cali_1 - error;
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return ESP_OK;
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}
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/* ----------------------- Characterization Functions ----------------------- */
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//To get the reference point (Dout, Vin)
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static void get_first_step_reference_point(int version_num, adc_unit_t unit_id, adc_atten_t atten, adc_calib_info_t *calib_info)
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{
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assert((version_num >= ESP_EFUSE_ADC_CALIB_VER_MIN) &&
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(version_num <= ESP_EFUSE_ADC_CALIB_VER_MAX));
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esp_err_t ret;
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calib_info->version_num = version_num;
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calib_info->unit_id = unit_id;
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calib_info->atten = atten;
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uint32_t voltage = 0;
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uint32_t digi = 0;
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ret = esp_efuse_rtc_calib_get_cal_voltage(version_num, unit_id, (int)atten, &digi, &voltage);
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assert(ret == ESP_OK);
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calib_info->ref_data.ver1.voltage = voltage;
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calib_info->ref_data.ver1.digi = digi;
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}
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/*
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* Estimate the (assumed) linear relationship btwn the measured raw value and the voltage
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* with the previously done measurement when the chip was manufactured.
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*/
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static void calc_first_step_coefficients(const adc_calib_info_t *parsed_data, cali_chars_curve_fitting_t *ctx)
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{
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ctx->chars_first_step.coeff_a = coeff_a_scaling * parsed_data->ref_data.ver1.voltage / parsed_data->ref_data.ver1.digi;
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ctx->chars_first_step.coeff_b = 0;
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ESP_LOGV(TAG, "Calib V1, Cal Voltage = %" PRId32 ", Digi out = %" PRId32 ", Coef_a = %" PRId32, parsed_data->ref_data.ver1.voltage, parsed_data->ref_data.ver1.digi, ctx->chars_first_step.coeff_a);
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}
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static int32_t get_reading_error(uint64_t v_cali_1, const cali_chars_second_step_t *param)
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{
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if (v_cali_1 == 0 || param->term_num == 0) {
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return 0;
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}
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uint8_t term_num = param->term_num;
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int32_t error = 0;
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uint64_t coeff = 0;
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uint64_t variable[term_num];
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uint64_t term[term_num];
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memset(variable, 0, term_num * sizeof(uint64_t));
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memset(term, 0, term_num * sizeof(uint64_t));
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/**
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* The scheme formula is:
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* error = (K0 * X^0) + (K1 * X^1) + (K2 * X^2) + (K3 * X^3) + ... + (Kn * X^n);
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*/
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variable[0] = 1;
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coeff = (param->coeff)[0][0];
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term[0] = variable[0] * coeff / (param->coeff)[0][1];
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error = (int32_t)term[0] * (param->sign)[0];
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for (int i = 1; i < term_num; i++) {
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variable[i] = variable[i - 1] * v_cali_1;
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coeff = (param->coeff)[i][0];
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term[i] = variable[i] * coeff;
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ESP_LOGV(TAG, "big coef is %llu, big term%d is %llu, coef_id is %d", coeff, i, term[i], i);
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term[i] = term[i] / (param->coeff)[i][1];
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error += (int32_t)term[i] * (param->sign)[i];
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ESP_LOGV(TAG, "term%d is %llu, error is %"PRId32, i, term[i], error);
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}
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return error;
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}
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static esp_err_t check_valid(const adc_cali_curve_fitting_config_t *config)
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{
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ESP_RETURN_ON_FALSE(config->unit_id < SOC_ADC_PERIPH_NUM, ESP_ERR_INVALID_ARG, TAG, "invalid ADC unit");
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ESP_RETURN_ON_FALSE(config->atten < SOC_ADC_ATTEN_NUM, ESP_ERR_INVALID_ARG, TAG, "invalid ADC attenuation");
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bool available_oneshot_bitwidth = (config->bitwidth >= SOC_ADC_RTC_MIN_BITWIDTH && config->bitwidth <= SOC_ADC_RTC_MAX_BITWIDTH);
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bool available_dma_bitwidth = (config->bitwidth >= SOC_ADC_DIGI_MIN_BITWIDTH && config->bitwidth <= SOC_ADC_DIGI_MAX_BITWIDTH);
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bool default_bitwidth_mark = (config->bitwidth == ADC_BITWIDTH_DEFAULT);
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bool available_bitwidth = (available_oneshot_bitwidth || available_dma_bitwidth || default_bitwidth_mark);
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ESP_RETURN_ON_FALSE(available_bitwidth, ESP_ERR_INVALID_ARG, TAG, "invalid bitwidth");
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return ESP_OK;
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}
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#endif //#if ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED
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