123 lines
4.5 KiB
C
123 lines
4.5 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) 2019 Dan Halbert for Adafruit Industries
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* Copyright (c) 2016 Scott Shawcroft 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/runtime.h"
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#include "supervisor/shared/translate.h"
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#include "nrf_saadc.h"
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#include "nrf_gpio.h"
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#define CHANNEL_NO 0
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void analogin_init(void) {
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// Calibrate the ADC once, on startup.
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nrf_saadc_enable(NRF_SAADC);
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nrf_saadc_event_clear(NRF_SAADC, NRF_SAADC_EVENT_CALIBRATEDONE);
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nrf_saadc_task_trigger(NRF_SAADC, NRF_SAADC_TASK_CALIBRATEOFFSET);
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while (nrf_saadc_event_check(NRF_SAADC, NRF_SAADC_EVENT_CALIBRATEDONE) == 0) { }
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nrf_saadc_event_clear(NRF_SAADC, NRF_SAADC_EVENT_CALIBRATEDONE);
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nrf_saadc_disable(NRF_SAADC);
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}
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void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self, const mcu_pin_obj_t *pin) {
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if (pin->adc_channel == 0)
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mp_raise_ValueError(translate("Pin does not have ADC capabilities"));
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nrf_gpio_cfg_default(pin->number);
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claim_pin(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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nrf_gpio_cfg_default(self->pin->number);
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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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// Something else might have used the ADC in a different way,
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// so we completely re-initialize it.
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nrf_saadc_value_t value;
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const nrf_saadc_channel_config_t config = {
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.resistor_p = NRF_SAADC_RESISTOR_DISABLED,
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.resistor_n = NRF_SAADC_RESISTOR_DISABLED,
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.gain = NRF_SAADC_GAIN1_4,
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.reference = NRF_SAADC_REFERENCE_VDD4,
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.acq_time = NRF_SAADC_ACQTIME_3US,
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.mode = NRF_SAADC_MODE_SINGLE_ENDED,
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.burst = NRF_SAADC_BURST_DISABLED
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};
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nrf_saadc_resolution_set(NRF_SAADC, NRF_SAADC_RESOLUTION_14BIT);
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nrf_saadc_oversample_set(NRF_SAADC, NRF_SAADC_OVERSAMPLE_DISABLED);
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nrf_saadc_enable(NRF_SAADC);
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for (uint32_t i = 0; i < SAADC_CH_NUM; i++)
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nrf_saadc_channel_input_set(NRF_SAADC, i, NRF_SAADC_INPUT_DISABLED, NRF_SAADC_INPUT_DISABLED);
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nrf_saadc_channel_init(NRF_SAADC, CHANNEL_NO, &config);
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nrf_saadc_channel_input_set(NRF_SAADC, CHANNEL_NO, self->pin->adc_channel, self->pin->adc_channel);
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nrf_saadc_buffer_init(NRF_SAADC, &value, 1);
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nrf_saadc_task_trigger(NRF_SAADC, NRF_SAADC_TASK_START);
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while (nrf_saadc_event_check(NRF_SAADC, NRF_SAADC_EVENT_STARTED) == 0);
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nrf_saadc_event_clear(NRF_SAADC, NRF_SAADC_EVENT_STARTED);
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nrf_saadc_task_trigger(NRF_SAADC, NRF_SAADC_TASK_SAMPLE);
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while (nrf_saadc_event_check(NRF_SAADC, NRF_SAADC_EVENT_END) == 0);
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nrf_saadc_event_clear(NRF_SAADC, NRF_SAADC_EVENT_END);
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nrf_saadc_task_trigger(NRF_SAADC, NRF_SAADC_TASK_STOP);
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while (nrf_saadc_event_check(NRF_SAADC, NRF_SAADC_EVENT_STOPPED) == 0);
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nrf_saadc_event_clear(NRF_SAADC, NRF_SAADC_EVENT_STOPPED);
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nrf_saadc_disable(NRF_SAADC);
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if (value < 0)
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value = 0;
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// Map value to from 14 to 16 bits
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return (value << 2);
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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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// The nominal VCC voltage
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return 3.3f;
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}
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