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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2020-2021 Damien P. George
*
* 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 "py/runtime.h"
#include "py/mphal.h"
#include "hardware/adc.h"
#define ADC_IS_VALID_GPIO(gpio) ((gpio) >= 26 && (gpio) <= 29)
#define ADC_CHANNEL_FROM_GPIO(gpio) ((gpio) - 26)
#define ADC_CHANNEL_TEMPSENSOR (4)
STATIC uint16_t adc_config_and_read_u16(uint32_t channel) {
adc_select_input(channel);
uint32_t raw = adc_read();
const uint32_t bits = 12;
// Scale raw reading to 16 bit value using a Taylor expansion (for 8 <= bits <= 16)
return raw << (16 - bits) | raw >> (2 * bits - 16);
}
/******************************************************************************/
// MicroPython bindings for machine.ADC
const mp_obj_type_t machine_adc_type;
typedef struct _machine_adc_obj_t {
mp_obj_base_t base;
uint32_t channel;
} machine_adc_obj_t;
STATIC void machine_adc_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
machine_adc_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_printf(print, "<ADC channel=%u>", self->channel);
}
// ADC(id)
STATIC mp_obj_t machine_adc_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
// Check number of arguments
mp_arg_check_num(n_args, n_kw, 1, 1, false);
mp_obj_t source = all_args[0];
uint32_t channel;
if (mp_obj_is_int(source)) {
// Get and validate channel number.
channel = mp_obj_get_int(source);
if (!((channel >= 0 && channel <= ADC_CHANNEL_TEMPSENSOR) || ADC_IS_VALID_GPIO(channel))) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid channel"));
}
} else {
// Get GPIO and check it has ADC capabilities.
channel = mp_hal_get_pin_obj(source);
if (!ADC_IS_VALID_GPIO(channel)) {
mp_raise_ValueError(MP_ERROR_TEXT("Pin doesn't have ADC capabilities"));
}
}
// Initialise the ADC peripheral if it's not already running.
if (!(adc_hw->cs & ADC_CS_EN_BITS)) {
adc_init();
}
if (ADC_IS_VALID_GPIO(channel)) {
// Configure the GPIO pin in ADC mode.
adc_gpio_init(channel);
channel = ADC_CHANNEL_FROM_GPIO(channel);
} else if (channel == ADC_CHANNEL_TEMPSENSOR) {
// Enable temperature sensor.
adc_set_temp_sensor_enabled(1);
}
// Create ADC object.
machine_adc_obj_t *o = m_new_obj(machine_adc_obj_t);
o->base.type = &machine_adc_type;
o->channel = channel;
return MP_OBJ_FROM_PTR(o);
}
// read_u16()
STATIC mp_obj_t machine_adc_read_u16(mp_obj_t self_in) {
machine_adc_obj_t *self = MP_OBJ_TO_PTR(self_in);
return MP_OBJ_NEW_SMALL_INT(adc_config_and_read_u16(self->channel));
}
MP_DEFINE_CONST_FUN_OBJ_1(machine_adc_read_u16_obj, machine_adc_read_u16);
STATIC const mp_rom_map_elem_t machine_adc_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_read_u16), MP_ROM_PTR(&machine_adc_read_u16_obj) },
{ MP_ROM_QSTR(MP_QSTR_CORE_TEMP), MP_ROM_INT(ADC_CHANNEL_TEMPSENSOR) },
};
STATIC MP_DEFINE_CONST_DICT(machine_adc_locals_dict, machine_adc_locals_dict_table);
const mp_obj_type_t machine_adc_type = {
{ &mp_type_type },
.name = MP_QSTR_ADC,
.print = machine_adc_print,
.make_new = machine_adc_make_new,
.locals_dict = (mp_obj_dict_t *)&machine_adc_locals_dict,
};
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