124 lines
4.4 KiB
C
124 lines
4.4 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) 2020-2021 Damien P. George
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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 "py/runtime.h"
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#include "py/mphal.h"
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#include "hardware/adc.h"
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#define ADC_IS_VALID_GPIO(gpio) ((gpio) >= 26 && (gpio) <= 29)
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#define ADC_CHANNEL_FROM_GPIO(gpio) ((gpio) - 26)
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#define ADC_CHANNEL_TEMPSENSOR (4)
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STATIC uint16_t adc_config_and_read_u16(uint32_t channel) {
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adc_select_input(channel);
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uint32_t raw = adc_read();
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const uint32_t bits = 12;
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// Scale raw reading to 16 bit value using a Taylor expansion (for 8 <= bits <= 16)
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return raw << (16 - bits) | raw >> (2 * bits - 16);
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}
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/******************************************************************************/
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// MicroPython bindings for machine.ADC
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const mp_obj_type_t machine_adc_type;
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typedef struct _machine_adc_obj_t {
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mp_obj_base_t base;
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uint32_t channel;
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} machine_adc_obj_t;
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STATIC void machine_adc_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
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machine_adc_obj_t *self = MP_OBJ_TO_PTR(self_in);
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mp_printf(print, "<ADC channel=%u>", self->channel);
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}
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// ADC(id)
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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) {
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// Check number of arguments
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mp_arg_check_num(n_args, n_kw, 1, 1, false);
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mp_obj_t source = all_args[0];
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uint32_t channel;
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if (mp_obj_is_int(source)) {
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// Get and validate channel number.
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channel = mp_obj_get_int(source);
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if (!((channel >= 0 && channel <= ADC_CHANNEL_TEMPSENSOR) || ADC_IS_VALID_GPIO(channel))) {
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mp_raise_ValueError(MP_ERROR_TEXT("invalid channel"));
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}
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} else {
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// Get GPIO and check it has ADC capabilities.
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channel = mp_hal_get_pin_obj(source);
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if (!ADC_IS_VALID_GPIO(channel)) {
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mp_raise_ValueError(MP_ERROR_TEXT("Pin doesn't have ADC capabilities"));
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}
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}
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// Initialise the ADC peripheral if it's not already running.
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if (!(adc_hw->cs & ADC_CS_EN_BITS)) {
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adc_init();
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}
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if (ADC_IS_VALID_GPIO(channel)) {
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// Configure the GPIO pin in ADC mode.
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adc_gpio_init(channel);
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channel = ADC_CHANNEL_FROM_GPIO(channel);
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} else if (channel == ADC_CHANNEL_TEMPSENSOR) {
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// Enable temperature sensor.
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adc_set_temp_sensor_enabled(1);
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}
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// Create ADC object.
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machine_adc_obj_t *o = m_new_obj(machine_adc_obj_t);
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o->base.type = &machine_adc_type;
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o->channel = channel;
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return MP_OBJ_FROM_PTR(o);
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}
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// read_u16()
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STATIC mp_obj_t machine_adc_read_u16(mp_obj_t self_in) {
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machine_adc_obj_t *self = MP_OBJ_TO_PTR(self_in);
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return MP_OBJ_NEW_SMALL_INT(adc_config_and_read_u16(self->channel));
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}
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MP_DEFINE_CONST_FUN_OBJ_1(machine_adc_read_u16_obj, machine_adc_read_u16);
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STATIC const mp_rom_map_elem_t machine_adc_locals_dict_table[] = {
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{ MP_ROM_QSTR(MP_QSTR_read_u16), MP_ROM_PTR(&machine_adc_read_u16_obj) },
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{ MP_ROM_QSTR(MP_QSTR_CORE_TEMP), MP_ROM_INT(ADC_CHANNEL_TEMPSENSOR) },
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};
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STATIC MP_DEFINE_CONST_DICT(machine_adc_locals_dict, machine_adc_locals_dict_table);
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const mp_obj_type_t machine_adc_type = {
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{ &mp_type_type },
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.name = MP_QSTR_ADC,
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.print = machine_adc_print,
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.make_new = machine_adc_make_new,
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.locals_dict = (mp_obj_dict_t *)&machine_adc_locals_dict,
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};
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