99 lines
3.8 KiB
C
99 lines
3.8 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2020 Lucian Copeland for Adafruit Industries
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "common-hal/analogio/AnalogIn.h"
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#include "py/mperrno.h"
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#include "py/runtime.h"
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#include "supervisor/shared/translate.h"
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#include "components/driver/include/driver/adc_common.h"
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#include "components/esp_adc_cal/include/esp_adc_cal.h"
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#include "shared-bindings/microcontroller/Pin.h"
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#define DEFAULT_VREF 1100
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#define NO_OF_SAMPLES 64
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#define ATTENUATION ADC_ATTEN_DB_11
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#define DATA_WIDTH ADC_WIDTH_BIT_13
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void common_hal_analogio_analogin_construct(analogio_analogin_obj_t* self,
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const mcu_pin_obj_t *pin) {
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if (pin->adc_index == 0 || pin->adc_channel == ADC_CHANNEL_MAX) {
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mp_raise_ValueError(translate("Pin does not have ADC capabilities"));
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}
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common_hal_mcu_pin_claim(pin);
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self->pin = pin;
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}
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bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
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return self->pin == NULL;
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}
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void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
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if (common_hal_analogio_analogin_deinited(self)) {
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return;
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}
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reset_pin_number(self->pin->number);
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self->pin = NULL;
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}
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uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
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if (self->pin->adc_index == ADC_UNIT_1) {
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adc1_config_width(DATA_WIDTH);
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adc1_config_channel_atten((adc1_channel_t)self->pin->adc_channel, ATTENUATION);
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} else if (self->pin->adc_index == ADC_UNIT_2) {
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adc2_config_channel_atten((adc2_channel_t)self->pin->adc_channel, ATTENUATION);
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}
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// Automatically select calibration process depending on status of efuse
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esp_adc_cal_characteristics_t *adc_chars = calloc(1, sizeof(esp_adc_cal_characteristics_t));
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esp_adc_cal_characterize(self->pin->adc_index, ATTENUATION, DATA_WIDTH, DEFAULT_VREF, adc_chars);
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uint32_t adc_reading = 0;
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//Multisampling
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for (int i = 0; i < NO_OF_SAMPLES; i++) {
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if (self->pin->adc_index == ADC_UNIT_1) {
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adc_reading += adc1_get_raw((adc1_channel_t)self->pin->adc_channel);
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} else {
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int raw;
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esp_err_t r = adc2_get_raw((adc2_channel_t)self->pin->adc_channel, DATA_WIDTH, &raw);
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if ( r != ESP_OK ) {
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mp_raise_ValueError(translate("ADC2 is being used by WiFi"));
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}
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adc_reading += raw;
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}
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}
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adc_reading /= NO_OF_SAMPLES;
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// This corrects non-linear regions of the ADC range with a LUT, so it's a better reading than raw
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uint32_t voltage = esp_adc_cal_raw_to_voltage(adc_reading, adc_chars);
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return voltage * ((1 << 16) - 1)/3300;
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}
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float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self) {
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return 3.3f;
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}
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