ESP32-PaxCounter/src/adcread.cpp
2018-06-03 00:05:53 +02:00

81 lines
2.6 KiB
C++

#ifdef HAS_BATTERY_PROBE
/* ADC1 Example
This example code is in the Public Domain (or CC0 licensed, at your option.)
Unless required by applicable law or agreed to in writing, this
software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
CONDITIONS OF ANY KIND, either express or implied.
*/
#include "globals.h"
#include <driver/adc.h>
#include <esp_adc_cal.h>
#define DEFAULT_VREF 1100 // we use adc2_vref_to_gpio() to obtain a better estimate
#define NO_OF_SAMPLES 64 // we do multisampling
// Local logging tag
static const char TAG[] = "main";
static void check_efuse()
{
//Check if two point calibration values are burned into eFuse
if (esp_adc_cal_check_efuse(ESP_ADC_CAL_VAL_EFUSE_TP) == ESP_OK) {
ESP_LOGI(TAG,"eFuse Two Point: Supported");
} else {
ESP_LOGI(TAG,"eFuse Two Point: NOT supported");
}
//Check Vref is burned into eFuse
if (esp_adc_cal_check_efuse(ESP_ADC_CAL_VAL_EFUSE_VREF) == ESP_OK) {
ESP_LOGI(TAG,"eFuse Vref: Supported");
} else {
ESP_LOGI(TAG,"eFuse Vref: NOT supported");
}
}
static void print_char_val_type(esp_adc_cal_value_t val_type)
{
if (val_type == ESP_ADC_CAL_VAL_EFUSE_TP) {
ESP_LOGI(TAG,"Characterized using Two Point Value");
} else if (val_type == ESP_ADC_CAL_VAL_EFUSE_VREF) {
ESP_LOGI(TAG,"Characterized using eFuse Vref");
} else {
ESP_LOGI(TAG,"Characterized using Default Vref");
}
}
uint16_t read_voltage(void)
{
static const adc1_channel_t channel = HAS_BATTERY_PROBE;
static const adc_atten_t atten = ADC_ATTEN_DB_0;
static const adc_unit_t unit = ADC_UNIT_1;
//Check if Two Point or Vref are burned into eFuse
check_efuse();
//Configure ADC1
adc1_config_width(ADC_WIDTH_BIT_12);
adc1_config_channel_atten(channel, atten);
//Characterize ADC1
esp_adc_cal_characteristics_t *adc_chars = (esp_adc_cal_characteristics_t *) calloc(1, sizeof(esp_adc_cal_characteristics_t));
esp_adc_cal_value_t val_type = esp_adc_cal_characterize(unit, atten, ADC_WIDTH_BIT_12, DEFAULT_VREF, adc_chars);
print_char_val_type(val_type);
//sample ADC1
uint32_t adc_reading = 0;
//Multisampling
for (int i = 0; i < NO_OF_SAMPLES; i++) {
adc_reading += adc1_get_raw(channel);
}
adc_reading /= NO_OF_SAMPLES;
//Convert adc_reading to voltage in mV
uint32_t voltage = esp_adc_cal_raw_to_voltage(adc_reading, adc_chars);
ESP_LOGI(TAG,"Raw: %d\tVoltage: %dmV", adc_reading, voltage);
return voltage;
}
#endif // HAS_BATTERY_PROBE