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Correct ADC auto-range for ESP32-S2 variant (13 bit adc) (#3158)

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Co-authored-by: Otto Winter <otto@otto-winter.com>
This commit is contained in:
Carlos Garcia Saura 2022-06-03 06:07:35 +02:00 committed by GitHub
parent d0dda48932
commit dd24ffa24e
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1 changed files with 28 additions and 17 deletions
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45
esphome/components/adc/adc_sensor.cpp
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@ -15,10 +15,21 @@ namespace esphome {
namespace adc { namespace adc {
static const char *const TAG = "adc"; static const char *const TAG = "adc";
// 13 bits for S3 / 12 bit for all other esp32 variants
// create a const to avoid the repated cast to enum // 13bit for S2, and 12bit for all other esp32 variants
#ifdef USE_ESP32 #ifdef USE_ESP32
static const adc_bits_width_t ADC_WIDTH_MAX_SOC_BITS = static_cast<adc_bits_width_t>(ADC_WIDTH_MAX - 1); static const adc_bits_width_t ADC_WIDTH_MAX_SOC_BITS = static_cast<adc_bits_width_t>(ADC_WIDTH_MAX - 1);
#ifndef SOC_ADC_RTC_MAX_BITWIDTH
#if USE_ESP32_VARIANT_ESP32S2
static const int SOC_ADC_RTC_MAX_BITWIDTH = 13;
#else
static const int SOC_ADC_RTC_MAX_BITWIDTH = 12;
#endif
#endif
static const int ADC_MAX = (1 << SOC_ADC_RTC_MAX_BITWIDTH) - 1; // 4095 (12 bit) or 8191 (13 bit)
static const int ADC_HALF = (1 << SOC_ADC_RTC_MAX_BITWIDTH) >> 1; // 2048 (12 bit) or 4096 (13 bit)
#endif #endif
void ADCSensor::setup() { void ADCSensor::setup() {
@ -75,16 +86,16 @@ void ADCSensor::dump_config() {
} else { } else {
switch (this->attenuation_) { switch (this->attenuation_) {
case ADC_ATTEN_DB_0: case ADC_ATTEN_DB_0:
ESP_LOGCONFIG(TAG, " Attenuation: 0db (max 1.1V)"); ESP_LOGCONFIG(TAG, " Attenuation: 0db");
break; break;
case ADC_ATTEN_DB_2_5: case ADC_ATTEN_DB_2_5:
ESP_LOGCONFIG(TAG, " Attenuation: 2.5db (max 1.5V)"); ESP_LOGCONFIG(TAG, " Attenuation: 2.5db");
break; break;
case ADC_ATTEN_DB_6: case ADC_ATTEN_DB_6:
ESP_LOGCONFIG(TAG, " Attenuation: 6db (max 2.2V)"); ESP_LOGCONFIG(TAG, " Attenuation: 6db");
break; break;
case ADC_ATTEN_DB_11: case ADC_ATTEN_DB_11:
ESP_LOGCONFIG(TAG, " Attenuation: 11db (max 3.9V)"); ESP_LOGCONFIG(TAG, " Attenuation: 11db");
break; break;
default: // This is to satisfy the unused ADC_ATTEN_MAX default: // This is to satisfy the unused ADC_ATTEN_MAX
break; break;
@ -129,16 +140,16 @@ float ADCSensor::sample() {
return mv / 1000.0f; return mv / 1000.0f;
} }
int raw11, raw6 = 4095, raw2 = 4095, raw0 = 4095; int raw11, raw6 = ADC_MAX, raw2 = ADC_MAX, raw0 = ADC_MAX;
adc1_config_channel_atten(channel_, ADC_ATTEN_DB_11); adc1_config_channel_atten(channel_, ADC_ATTEN_DB_11);
raw11 = adc1_get_raw(channel_); raw11 = adc1_get_raw(channel_);
if (raw11 < 4095) { if (raw11 < ADC_MAX) {
adc1_config_channel_atten(channel_, ADC_ATTEN_DB_6); adc1_config_channel_atten(channel_, ADC_ATTEN_DB_6);
raw6 = adc1_get_raw(channel_); raw6 = adc1_get_raw(channel_);
if (raw6 < 4095) { if (raw6 < ADC_MAX) {
adc1_config_channel_atten(channel_, ADC_ATTEN_DB_2_5); adc1_config_channel_atten(channel_, ADC_ATTEN_DB_2_5);
raw2 = adc1_get_raw(channel_); raw2 = adc1_get_raw(channel_);
if (raw2 < 4095) { if (raw2 < ADC_MAX) {
adc1_config_channel_atten(channel_, ADC_ATTEN_DB_0); adc1_config_channel_atten(channel_, ADC_ATTEN_DB_0);
raw0 = adc1_get_raw(channel_); raw0 = adc1_get_raw(channel_);
} }
@ -154,15 +165,15 @@ float ADCSensor::sample() {
uint32_t mv2 = esp_adc_cal_raw_to_voltage(raw2, &cal_characteristics_[(int) ADC_ATTEN_DB_2_5]); uint32_t mv2 = esp_adc_cal_raw_to_voltage(raw2, &cal_characteristics_[(int) ADC_ATTEN_DB_2_5]);
uint32_t mv0 = esp_adc_cal_raw_to_voltage(raw0, &cal_characteristics_[(int) ADC_ATTEN_DB_0]); uint32_t mv0 = esp_adc_cal_raw_to_voltage(raw0, &cal_characteristics_[(int) ADC_ATTEN_DB_0]);
// Contribution of each value, in range 0-2048 // Contribution of each value, in range 0-2048 (12 bit ADC) or 0-4096 (13 bit ADC)
uint32_t c11 = std::min(raw11, 2048); uint32_t c11 = std::min(raw11, ADC_HALF);
uint32_t c6 = 2048 - std::abs(raw6 - 2048); uint32_t c6 = ADC_HALF - std::abs(raw6 - ADC_HALF);
uint32_t c2 = 2048 - std::abs(raw2 - 2048); uint32_t c2 = ADC_HALF - std::abs(raw2 - ADC_HALF);
uint32_t c0 = std::min(4095 - raw0, 2048); uint32_t c0 = std::min(ADC_MAX - raw0, ADC_HALF);
// max theoretical csum value is 2048*4 = 8192 // max theoretical csum value is 4096*4 = 16384
uint32_t csum = c11 + c6 + c2 + c0; uint32_t csum = c11 + c6 + c2 + c0;
// each mv is max 3900; so max value is 3900*2048*4, fits in unsigned // each mv is max 3900; so max value is 3900*4096*4, fits in unsigned32
uint32_t mv_scaled = (mv11 * c11) + (mv6 * c6) + (mv2 * c2) + (mv0 * c0); uint32_t mv_scaled = (mv11 * c11) + (mv6 * c6) + (mv2 * c2) + (mv0 * c0);
return mv_scaled / (float) (csum * 1000U); return mv_scaled / (float) (csum * 1000U);
} }