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Esp32 HAL - Dynamic ADC attenuation #14623

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Merged
thinkyhead merged 4 commits into from
Jul 15, 2019
Merged

Esp32 HAL - Dynamic ADC attenuation #14623

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adafc94
dynamic ADC attenuation level
Jul 12, 2019
1b41892
Update HAL.cpp
thinkyhead Jul 14, 2019
5545e35
Tweak attenuation (probably compiles the same)
thinkyhead Jul 15, 2019
e393a51
Update HAL.cpp
thinkyhead Jul 15, 2019
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53 changes: 40 additions & 13 deletions Marlin/src/HAL/HAL_ESP32/HAL.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -67,7 +67,9 @@ uint16_t HAL_adc_result;
// Private Variables
// ------------------------

esp_adc_cal_characteristics_t characteristics;
esp_adc_cal_characteristics_t characteristics[ADC_ATTEN_MAX];
adc_atten_t attenuations[ADC1_CHANNEL_MAX] = {};
uint32_t thresholds[ADC_ATTEN_MAX];
volatile int numPWMUsed = 0,
pwmPins[MAX_PWM_PINS],
pwmValues[MAX_PWM_PINS];
Expand Down Expand Up @@ -129,49 +131,74 @@ adc1_channel_t get_channel(int pin) {
return ADC1_CHANNEL_MAX;
}

void adc1_set_attenuation(adc1_channel_t chan, adc_atten_t atten) {
if (attenuations[chan] != atten) {
adc1_config_channel_atten(chan, atten);
attenuations[chan] = atten;
}
}

void HAL_adc_init() {
// Configure ADC
adc1_config_width(ADC_WIDTH_12Bit);

// Configure channels only if used as (re-)configuring a pin for ADC that is used elsewhere might have adverse effects
#if HAS_TEMP_ADC_0
adc1_config_channel_atten(get_channel(TEMP_0_PIN), ADC_ATTEN_11db);
adc1_set_attenuation(get_channel(TEMP_0_PIN), ADC_ATTEN_11db);
#endif
#if HAS_TEMP_ADC_1
adc1_config_channel_atten(get_channel(TEMP_1_PIN), ADC_ATTEN_11db);
adc1_set_attenuation(get_channel(TEMP_1_PIN), ADC_ATTEN_11db);
#endif
#if HAS_TEMP_ADC_2
adc1_config_channel_atten(get_channel(TEMP_2_PIN), ADC_ATTEN_11db);
adc1_set_attenuation(get_channel(TEMP_2_PIN), ADC_ATTEN_11db);
#endif
#if HAS_TEMP_ADC_3
adc1_config_channel_atten(get_channel(TEMP_3_PIN), ADC_ATTEN_11db);
adc1_set_attenuation(get_channel(TEMP_3_PIN), ADC_ATTEN_11db);
#endif
#if HAS_TEMP_ADC_4
adc1_config_channel_atten(get_channel(TEMP_4_PIN), ADC_ATTEN_11db);
adc1_set_attenuation(get_channel(TEMP_4_PIN), ADC_ATTEN_11db);
#endif
#if HAS_TEMP_ADC_5
adc1_config_channel_atten(get_channel(TEMP_5_PIN), ADC_ATTEN_11db);
adc1_set_attenuation(get_channel(TEMP_5_PIN), ADC_ATTEN_11db);
#endif
#if HAS_HEATED_BED
adc1_config_channel_atten(get_channel(TEMP_BED_PIN), ADC_ATTEN_11db);
adc1_set_attenuation(get_channel(TEMP_BED_PIN), ADC_ATTEN_11db);
#endif
#if HAS_TEMP_CHAMBER
adc1_config_channel_atten(get_channel(TEMP_CHAMBER_PIN), ADC_ATTEN_11db);
adc1_set_attenuation(get_channel(TEMP_CHAMBER_PIN), ADC_ATTEN_11db);
#endif
#if ENABLED(FILAMENT_WIDTH_SENSOR)
adc1_config_channel_atten(get_channel(FILWIDTH_PIN), ADC_ATTEN_11db);
adc1_set_attenuation(get_channel(FILWIDTH_PIN), ADC_ATTEN_11db);
#endif

// Note that adc2 is shared with the WiFi module, which has higher priority, so the conversion may fail.
// That's why we're not setting it up here.

// Calculate ADC characteristics i.e. gain and offset factors
esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_11, ADC_WIDTH_BIT_12, V_REF, &characteristics);
// Calculate ADC characteristics (i.e., gain and offset factors for each attenuation level)
for (int i = 0; i < ADC_ATTEN_MAX; i++) {
esp_adc_cal_characterize(ADC_UNIT_1, (adc_atten_t)i, ADC_WIDTH_BIT_12, V_REF, &characteristics[i]);

// Change attenuation 100mV below the calibrated threshold
thresholds[i] = esp_adc_cal_raw_to_voltage(4095, &characteristics[i]);
}
}

void HAL_adc_start_conversion(uint8_t adc_pin) {
const adc1_channel_t chan = get_channel(adc_pin);
uint32_t mv;
esp_adc_cal_get_voltage((adc_channel_t)get_channel(adc_pin), &characteristics, &mv);
esp_adc_cal_get_voltage((adc_channel_t)chan, &characteristics[attenuations[chan]], &mv);

// Change the attenuation level based on the new reading
adc_atten_t atten;
if (mv < thresholds[ADC_ATTEN_DB_0] - 100)
adc1_set_attenuation(chan, ADC_ATTEN_DB_0);
else if (mv > thresholds[ADC_ATTEN_DB_0] - 50 && mv < thresholds[ADC_ATTEN_DB_2_5] - 100)
adc1_set_attenuation(chan, ADC_ATTEN_DB_2_5);
else if (mv > thresholds[ADC_ATTEN_DB_2_5] - 50 && mv < thresholds[ADC_ATTEN_DB_6] - 100)
adc1_set_attenuation(chan, ADC_ATTEN_DB_6);
else if (mv > thresholds[ADC_ATTEN_DB_6] - 50)
adc1_set_attenuation(chan, ADC_ATTEN_DB_11);

HAL_adc_result = mv * 1023.0 / 3300.0;
}

Expand Down