56 lines
1.9 KiB
C++
56 lines
1.9 KiB
C++
#ifdef HAS_BATTERY_PROBE
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#include "globals.h"
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#include <driver/adc.h>
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#include <esp_adc_cal.h>
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#define DEFAULT_VREF 1100 // to be done: use adc2_vref_to_gpio() to obtain a better estimate
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#define NO_OF_SAMPLES 64 // we do multisampling
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// Local logging tag
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static const char TAG[] = "main";
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static void print_char_val_type(esp_adc_cal_value_t val_type)
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{
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if (val_type == ESP_ADC_CAL_VAL_EFUSE_TP) {
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ESP_LOGI(TAG,"ADC characterization based on Two Point values stored in eFuse");
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} else if (val_type == ESP_ADC_CAL_VAL_EFUSE_VREF) {
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ESP_LOGI(TAG,"ADC characterization based on reference voltage stored in eFuse");
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} else {
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ESP_LOGI(TAG,"ADC characterization based on default reference voltage");
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}
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}
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uint16_t read_voltage(void)
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{
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static const adc1_channel_t channel = HAS_BATTERY_PROBE;
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static const adc_atten_t atten = ADC_ATTEN_DB_11;
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static const adc_unit_t unit = ADC_UNIT_1;
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//configure ADC1
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ESP_ERROR_CHECK(adc1_config_width(ADC_WIDTH_BIT_12));
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ESP_ERROR_CHECK(adc1_config_channel_atten(channel, atten));
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//calibrate ADC1
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esp_adc_cal_characteristics_t *adc_chars = (esp_adc_cal_characteristics_t *) calloc(1, sizeof(esp_adc_cal_characteristics_t));
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esp_adc_cal_value_t val_type = esp_adc_cal_characterize(unit, atten, ADC_WIDTH_BIT_12, DEFAULT_VREF, adc_chars);
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print_char_val_type(val_type);
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//multisample ADC1
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uint32_t adc_reading = 0;
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for (int i = 0; i < NO_OF_SAMPLES; i++) {
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adc_reading += adc1_get_raw(channel);
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}
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adc_reading /= NO_OF_SAMPLES;
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//Convert adc_reading to voltage in mV
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uint16_t voltage = (uint16_t) esp_adc_cal_raw_to_voltage(adc_reading, adc_chars);
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#ifdef BATT_FACTOR
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voltage *= BATT_FACTOR;
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#endif
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ESP_LOGI(TAG,"Raw: %d / Voltage: %dmV", adc_reading, voltage);
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return voltage;
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}
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#endif // HAS_BATTERY_PROBE
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