7f36a365cf
.. otherwise, depending on the prior state of the pin as a digital input, the value read could be 20% low.
103 lines
3.6 KiB
C
103 lines
3.6 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) 2021 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 "shared-bindings/analogio/AnalogIn.h"
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#include "shared-bindings/microcontroller/__init__.h"
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#include "shared-bindings/microcontroller/Pin.h"
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#include "py/runtime.h"
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#include "supervisor/shared/translate/translate.h"
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#include "src/rp2_common/hardware_adc/include/hardware/adc.h"
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#define ADC_FIRST_PIN_NUMBER 26
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#define ADC_PIN_COUNT 4
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// Voltage monitor is special on Pico W, because this pin is shared between the
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// voltage monitor function and the wifi function. Special handling is required
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// to read the analog voltage.
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#if CIRCUITPY_CYW43
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#define SPECIAL_PIN(pin) (pin->number == 29)
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#else
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#define SPECIAL_PIN(pin) false
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#endif
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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->number < ADC_FIRST_PIN_NUMBER || pin->number > ADC_FIRST_PIN_NUMBER + ADC_PIN_COUNT) {
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raise_ValueError_invalid_pin();
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}
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adc_init();
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if (!SPECIAL_PIN(pin)) {
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adc_gpio_init(pin->number);
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claim_pin(pin);
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}
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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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if (!SPECIAL_PIN(self->pin)) {
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reset_pin_number(self->pin->number);
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}
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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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uint16_t value;
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if (SPECIAL_PIN(self->pin)) {
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common_hal_mcu_disable_interrupts();
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uint32_t old_pad = padsbank0_hw->io[self->pin->number];
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uint32_t old_ctrl = iobank0_hw->io[self->pin->number].ctrl;
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adc_gpio_init(self->pin->number);
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adc_select_input(self->pin->number - ADC_FIRST_PIN_NUMBER);
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common_hal_mcu_delay_us(100);
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value = adc_read();
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gpio_init(self->pin->number);
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padsbank0_hw->io[self->pin->number] = old_pad;
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iobank0_hw->io[self->pin->number].ctrl = old_ctrl;
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common_hal_mcu_enable_interrupts();
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} else {
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adc_select_input(self->pin->number - ADC_FIRST_PIN_NUMBER);
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value = adc_read();
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}
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// Stretch 12-bit ADC reading to 16-bit range
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return (value << 4) | (value >> 8);
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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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