1 /*
2 * SPDX-FileCopyrightText: 2020-2021 Espressif Systems (Shanghai) CO LTD
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <stdint.h>
8 #include <string.h>
9 #include "esp_types.h"
10 #include "esp_err.h"
11 #include "esp_log.h"
12 #include "esp_check.h"
13 #include "driver/adc.h"
14 #include "hal/adc_types.h"
15 #include "esp_adc_cal.h"
16 #include "esp_adc_cal_internal.h"
17
18 const static char *TAG = "ADC_CALI";
19
esp_adc_cal_get_voltage(adc_channel_t channel,const esp_adc_cal_characteristics_t * chars,uint32_t * voltage)20 esp_err_t esp_adc_cal_get_voltage(adc_channel_t channel,
21 const esp_adc_cal_characteristics_t *chars,
22 uint32_t *voltage)
23 {
24 // Check parameters
25 ESP_RETURN_ON_FALSE(chars != NULL, ESP_ERR_INVALID_ARG, TAG, "No characteristic input");
26 ESP_RETURN_ON_FALSE(voltage != NULL, ESP_ERR_INVALID_ARG, TAG, "No output buffer");
27
28 esp_err_t ret = ESP_OK;
29 int adc_reading;
30 if (chars->adc_num == ADC_UNIT_1) {
31 ESP_RETURN_ON_FALSE(channel < SOC_ADC_CHANNEL_NUM(0), ESP_ERR_INVALID_ARG, TAG, "Invalid channel");
32 adc_reading = adc1_get_raw(channel);
33 } else {
34 ESP_RETURN_ON_FALSE(channel < SOC_ADC_CHANNEL_NUM(1), ESP_ERR_INVALID_ARG, TAG, "Invalid channel");
35 ret = adc2_get_raw(channel, chars->bit_width, &adc_reading);
36 }
37 *voltage = esp_adc_cal_raw_to_voltage((uint32_t)adc_reading, chars);
38 return ret;
39 }
40
41 #if ESP_ADC_CAL_CURVE_FITTING_SUPPORTED
42 /*------------------------------------------------------------------------------
43 * Private API
44 *----------------------------------------------------------------------------*/
esp_adc_cal_get_reading_error(const esp_adc_error_calc_param_t * param,uint8_t atten)45 int32_t esp_adc_cal_get_reading_error(const esp_adc_error_calc_param_t *param, uint8_t atten)
46 {
47 if (param->v_cali_input == 0) {
48 return 0;
49 }
50
51 uint64_t v_cali_1 = param->v_cali_input;
52 uint8_t term_num = param->term_num;
53 int32_t error = 0;
54 uint64_t coeff = 0;
55 uint64_t variable[term_num];
56 uint64_t term[term_num];
57 memset(variable, 0, term_num * sizeof(uint64_t));
58 memset(term, 0, term_num * sizeof(uint64_t));
59
60 /**
61 * For atten0 ~ 2:
62 * error = (K0 * X^0) + (K1 * X^1) + (K2 * X^2);
63 *
64 * For atten3:
65 * error = (K0 * X^0) + (K1 * X^1) + (K2 * X^2) + (K3 * X^3) + (K4 * X^4);
66 */
67 variable[0] = 1;
68 coeff = (*param->coeff)[atten][0][0];
69 term[0] = variable[0] * coeff / (*param->coeff)[atten][0][1];
70 error = (int32_t)term[0] * (*param->sign)[atten][0];
71
72 for (int i = 1; i < term_num; i++) {
73 variable[i] = variable[i-1] * v_cali_1;
74 coeff = (*param->coeff)[atten][i][0];
75 term[i] = variable[i] * coeff;
76 ESP_LOGV(TAG, "big coef is %llu, big term%d is %llu, coef_id is %d", coeff, i, term[i], i);
77
78 term[i] = term[i] / (*param->coeff)[atten][i][1];
79 error += (int32_t)term[i] * (*param->sign)[atten][i];
80 ESP_LOGV(TAG, "term%d is %llu, error is %d", i, term[i], error);
81 }
82
83 return error;
84 }
85 #endif //#if ESP_ADC_CAL_CURVE_FITTING_SUPPORTED
86
