circuitpython/ports/raspberrypi/common-hal/analogio/AnalogIn.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2021 Scott Shawcroft for Adafruit Industries
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "common-hal/analogio/AnalogIn.h"
#include "shared-bindings/analogio/AnalogIn.h"
#include "shared-bindings/microcontroller/__init__.h"
#include "shared-bindings/microcontroller/Pin.h"
#include "py/runtime.h"
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#include "supervisor/shared/translate/translate.h"
#include "src/rp2_common/hardware_adc/include/hardware/adc.h"
#define ADC_FIRST_PIN_NUMBER 26
#define ADC_PIN_COUNT 4
// Voltage monitor is special on Pico W, because this pin is shared between the
// voltage monitor function and the wifi function. Special handling is required
// to read the analog voltage.
#if CIRCUITPY_CYW43
#include "bindings/cyw43/__init__.h"
#define SPECIAL_PIN(pin) (pin->number == 29)
const mcu_pin_obj_t *common_hal_analogio_analogin_validate_pin(mp_obj_t obj) {
return validate_obj_is_free_pin_or_gpio29(obj, MP_QSTR_pin);
}
#else
#define SPECIAL_PIN(pin) false
#endif
void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self, const mcu_pin_obj_t *pin) {
if (pin->number < ADC_FIRST_PIN_NUMBER || pin->number > ADC_FIRST_PIN_NUMBER + ADC_PIN_COUNT) {
raise_ValueError_invalid_pin();
}
adc_init();
if (!SPECIAL_PIN(pin)) {
adc_gpio_init(pin->number);
claim_pin(pin);
}
self->pin = pin;
}
bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
return self->pin == NULL;
}
void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
if (common_hal_analogio_analogin_deinited(self)) {
return;
}
if (!SPECIAL_PIN(self->pin)) {
reset_pin_number(self->pin->number);
}
self->pin = NULL;
}
uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
uint16_t value;
if (SPECIAL_PIN(self->pin)) {
common_hal_mcu_disable_interrupts();
uint32_t old_pad = padsbank0_hw->io[self->pin->number];
uint32_t old_ctrl = iobank0_hw->io[self->pin->number].ctrl;
adc_gpio_init(self->pin->number);
adc_select_input(self->pin->number - ADC_FIRST_PIN_NUMBER);
common_hal_mcu_delay_us(100);
value = adc_read();
gpio_init(self->pin->number);
padsbank0_hw->io[self->pin->number] = old_pad;
iobank0_hw->io[self->pin->number].ctrl = old_ctrl;
common_hal_mcu_enable_interrupts();
} else {
adc_select_input(self->pin->number - ADC_FIRST_PIN_NUMBER);
value = adc_read();
}
// Stretch 12-bit ADC reading to 16-bit range
return (value << 4) | (value >> 8);
}
float common_hal_analogio_analogin_get_reference_voltage(analogio_analogin_obj_t *self) {
// The nominal VCC voltage
return 3.3f;
}