175 lines
6.2 KiB
C
175 lines
6.2 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 "bindings/espidf/__init__.h"
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#include "shared-bindings/analogio/AnalogIn.h"
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#include "py/mperrno.h"
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#include "py/runtime.h"
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#include "adc_cali_schemes.h"
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#include "esp_adc/adc_oneshot.h"
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#include "esp_adc/adc_cali.h"
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#include "driver/gpio.h"
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#include "hal/adc_types.h"
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#include "shared-bindings/microcontroller/Pin.h"
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#include <string.h>
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#define DEFAULT_VREF 1100
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#define NO_OF_SAMPLES 2
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#define ATTENUATION ADC_ATTEN_DB_11
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#if defined(CONFIG_IDF_TARGET_ESP32)
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#define DATA_WIDTH ADC_BITWIDTH_12
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#elif defined(CONFIG_IDF_TARGET_ESP32C3)
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#define DATA_WIDTH ADC_BITWIDTH_12
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#elif defined(CONFIG_IDF_TARGET_ESP32C6)
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#define DATA_WIDTH ADC_BITWIDTH_12
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#elif defined(CONFIG_IDF_TARGET_ESP32S2)
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#define DATA_WIDTH ADC_BITWIDTH_13
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#elif defined(CONFIG_IDF_TARGET_ESP32S3)
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#define DATA_WIDTH ADC_BITWIDTH_12
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#elif defined(CONFIG_IDF_TARGET_ESP32H2)
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#define DATA_WIDTH ADC_BITWIDTH_12
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#else
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#error No known CONFIG_IDF_TARGET_xxx found
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#endif
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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 == NO_ADC || pin->adc_channel == NO_ADC_CHANNEL) {
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raise_ValueError_invalid_pin();
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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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// Pull-ups are enabled by default for power-saving reasons on quiescent pins.
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// Turn off the pull-up as soon as we know the pin will be used for analog reads,
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// since it may take a while for the voltage to stabilize if the input is high-impedance.
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gpio_pullup_dis(pin->number);
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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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adc_oneshot_unit_handle_t adc_handle;
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adc_oneshot_unit_init_cfg_t adc_config = {
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.unit_id = self->pin->adc_index,
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.ulp_mode = ADC_ULP_MODE_DISABLE
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};
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cp_check_esp_error(adc_oneshot_new_unit(&adc_config, &adc_handle));
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adc_oneshot_chan_cfg_t channel_config = {
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.atten = ATTENUATION,
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.bitwidth = DATA_WIDTH
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};
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adc_channel_t channel = (adc_channel_t)self->pin->adc_channel;
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adc_oneshot_config_channel(adc_handle, channel, &channel_config);
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adc_cali_scheme_ver_t supported_schemes;
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adc_cali_check_scheme(&supported_schemes);
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adc_cali_scheme_ver_t calibration_scheme = 0;
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adc_cali_handle_t calibration;
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#if defined(ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED
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adc_cali_curve_fitting_config_t config = {
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.unit_id = self->pin->adc_index,
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.chan = channel,
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.atten = ATTENUATION,
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.bitwidth = DATA_WIDTH
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};
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if (adc_cali_create_scheme_curve_fitting(&config, &calibration) == ESP_OK) {
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calibration_scheme = ADC_CALI_SCHEME_VER_CURVE_FITTING;
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}
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#endif
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#if defined(ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED
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if (calibration_scheme == 0) {
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adc_cali_line_fitting_config_t config = {
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.unit_id = self->pin->adc_index,
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.atten = ATTENUATION,
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.bitwidth = DATA_WIDTH,
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#ifdef CONFIG_IDF_TARGET_ESP32
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.default_vref = DEFAULT_VREF,
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#endif
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};
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if (adc_cali_create_scheme_line_fitting(&config, &calibration) == ESP_OK) {
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calibration_scheme = ADC_CALI_SCHEME_VER_LINE_FITTING;
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}
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}
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#endif
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uint32_t adc_reading = 0;
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size_t sample_count = 0;
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// Multisampling
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esp_err_t ret = ESP_OK;
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for (int i = 0; i < NO_OF_SAMPLES; i++) {
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int raw;
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ret = adc_oneshot_read(adc_handle, channel, &raw);
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if (ret != ESP_OK) {
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continue;
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}
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adc_reading += raw;
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sample_count += 1;
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}
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if (sample_count == 0) {
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raise_esp_error(ret);
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}
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adc_reading /= sample_count;
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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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int voltage;
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adc_cali_raw_to_voltage(calibration, adc_reading, &voltage);
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#if defined(ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_CURVE_FITTING_SUPPORTED
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if (calibration_scheme == ADC_CALI_SCHEME_VER_CURVE_FITTING) {
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adc_cali_delete_scheme_curve_fitting(calibration);
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}
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#endif
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#if defined(ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED) && ADC_CALI_SCHEME_LINE_FITTING_SUPPORTED
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if (calibration_scheme == ADC_CALI_SCHEME_VER_LINE_FITTING) {
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adc_cali_delete_scheme_line_fitting(calibration);
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}
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#endif
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adc_oneshot_del_unit(adc_handle);
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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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