5c7e93ec48
With the method read_u16(). Keyword arguments of the constructor are:
- bits=n The resolution; default is 12.
- average=n The average of samples, which are taken and cumulated. The
default value is 16. Averaging by hw is faster than averaging
in code.
The ADC runs at a clock freq 1.5 MHz. A single 12 bit conversion takes
8 microseconds.
239 lines
9.4 KiB
C
239 lines
9.4 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) 2021 Philipp Ebensberger
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* Copyright (c) 2022 Robert Hammelrath
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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 <stdint.h>
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#include "py/obj.h"
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#include "py/runtime.h"
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#include "py/mphal.h"
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#include "sam.h"
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#include "pin_af.h"
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#include "modmachine.h"
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typedef struct _machine_adc_obj_t {
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mp_obj_base_t base;
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adc_config_t adc_config;
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uint8_t id;
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uint8_t avg;
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uint8_t bits;
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} machine_adc_obj_t;
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#define DEFAULT_ADC_BITS 12
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#define DEFAULT_ADC_AVG 16
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Adc *const adc_bases[] = ADC_INSTS;
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uint32_t busy_flags = 0;
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bool init_flags[2] = {false, false};
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static void adc_init(machine_adc_obj_t *self);
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static uint8_t resolution[] = {
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ADC_CTRLB_RESSEL_8BIT_Val, ADC_CTRLB_RESSEL_10BIT_Val, ADC_CTRLB_RESSEL_12BIT_Val
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};
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// Calculate the floor value of log2(n)
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mp_int_t log2i(mp_int_t num) {
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mp_int_t res = 0;
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for (; num > 1; num >>= 1) {
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res += 1;
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}
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return res;
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}
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STATIC void adc_obj_print(const mp_print_t *print, mp_obj_t o, mp_print_kind_t kind) {
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(void)kind;
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machine_adc_obj_t *self = MP_OBJ_TO_PTR(o);
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mp_printf(print, "ADC(P%c%02u, ADC%u, channel=%u, bits=%u, average=%u)",
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"ABCD"[self->id / 32], self->id % 32, self->adc_config.device,
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self->adc_config.channel, self->bits, 1 << self->avg);
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}
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STATIC mp_obj_t adc_obj_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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enum { ARG_id, ARG_bits, ARG_average };
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static const mp_arg_t allowed_args[] = {
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{ MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ },
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{ MP_QSTR_bits, MP_ARG_INT, {.u_int = DEFAULT_ADC_BITS} },
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{ MP_QSTR_average, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_ADC_AVG} },
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};
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// Parse the arguments.
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mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
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mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
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// Unpack and check, whther the pin has ADC capability
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int id = mp_hal_get_pin_obj(args[ARG_id].u_obj);
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adc_config_t adc_config = get_adc_config(id, busy_flags);
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// Now that we have a valid device and channel, create and populate the ADC instance
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machine_adc_obj_t *self = mp_obj_malloc(machine_adc_obj_t, &machine_adc_type);
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self->id = id;
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self->adc_config = adc_config;
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self->bits = DEFAULT_ADC_BITS;
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uint16_t bits = args[ARG_bits].u_int;
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if (bits >= 8 && bits <= 12) {
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self->bits = bits;
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}
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uint32_t avg = log2i(args[ARG_average].u_int);
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self->avg = (avg <= 10 ? avg : 10);
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// flag the device/channel as being in use.
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busy_flags |= (1 << (self->adc_config.device * 16 + self->adc_config.channel));
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adc_init(self);
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return MP_OBJ_FROM_PTR(self);
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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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Adc *adc = adc_bases[self->adc_config.device];
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// Set Input channel and resolution
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// Select the pin as positive input and gnd as negative input reference, non-diff mode by default
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adc->INPUTCTRL.reg = ADC_INPUTCTRL_MUXNEG_GND | self->adc_config.channel;
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// set resolution. Scale 8-16 to 0 - 4 for table access.
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adc->CTRLB.bit.RESSEL = resolution[(self->bits - 8) / 2];
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// Measure input voltage
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adc->SWTRIG.bit.START = 1;
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while (adc->INTFLAG.bit.RESRDY == 0) {
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}
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// Get and return the result
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return MP_OBJ_NEW_SMALL_INT(adc->RESULT.reg * (65536 / (1 << self->bits)));
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_adc_read_u16_obj, machine_adc_read_u16);
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// deinit() : release the ADC channel
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STATIC mp_obj_t machine_adc_deinit(mp_obj_t self_in) {
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machine_adc_obj_t *self = MP_OBJ_TO_PTR(self_in);
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busy_flags &= ~((1 << (self->adc_config.device * 16 + self->adc_config.channel)));
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return mp_const_none;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_adc_deinit_obj, machine_adc_deinit);
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void adc_deinit_all(void) {
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busy_flags = 0;
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init_flags[0] = 0;
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init_flags[1] = 0;
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}
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STATIC const mp_rom_map_elem_t 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_deinit), MP_ROM_PTR(&machine_adc_deinit_obj) },
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};
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STATIC MP_DEFINE_CONST_DICT(adc_locals_dict, adc_locals_dict_table);
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MP_DEFINE_CONST_OBJ_TYPE(
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machine_adc_type,
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MP_QSTR_ADC,
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MP_TYPE_FLAG_NONE,
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make_new, adc_obj_make_new,
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print, adc_obj_print,
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locals_dict, &adc_locals_dict
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);
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static void adc_init(machine_adc_obj_t *self) {
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// ADC & clock init is done only once per ADC
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if (init_flags[self->adc_config.device] == false) {
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Adc *adc = adc_bases[self->adc_config.device];
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init_flags[self->adc_config.device] = true;
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#if defined(MCU_SAMD21)
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// Configuration SAMD21
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// Enable APBD clocks and PCHCTRL clocks; GCLK2 at 48 MHz
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PM->APBCMASK.reg |= PM_APBCMASK_ADC;
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GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK2 | GCLK_CLKCTRL_ID_ADC;
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while (GCLK->STATUS.bit.SYNCBUSY) {
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}
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// Reset ADC registers
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adc->CTRLA.bit.SWRST = 1;
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while (adc->CTRLA.bit.SWRST) {
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}
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// Get the calibration data
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uint32_t bias = (*((uint32_t *)ADC_FUSES_BIASCAL_ADDR) & ADC_FUSES_BIASCAL_Msk) >> ADC_FUSES_BIASCAL_Pos;
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uint32_t linearity = (*((uint32_t *)ADC_FUSES_LINEARITY_0_ADDR) & ADC_FUSES_LINEARITY_0_Msk) >> ADC_FUSES_LINEARITY_0_Pos;
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linearity |= ((*((uint32_t *)ADC_FUSES_LINEARITY_1_ADDR) & ADC_FUSES_LINEARITY_1_Msk) >> ADC_FUSES_LINEARITY_1_Pos) << 5;
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/* Write the calibration data. */
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ADC->CALIB.reg = ADC_CALIB_BIAS_CAL(bias) | ADC_CALIB_LINEARITY_CAL(linearity);
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// Divide 48MHz clock by 32 to obtain 1.5 MHz clock to adc
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adc->CTRLB.reg = ADC_CTRLB_PRESCALER_DIV32;
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// Select external AREFA as reference voltage.
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adc->REFCTRL.reg = ADC_REFCTRL_REFSEL_AREFA;
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// Average: Accumulate samples and scale them down accordingly
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adc->AVGCTRL.reg = self->avg | ADC_AVGCTRL_ADJRES(self->avg);
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// Enable ADC and wait to be ready
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adc->CTRLA.bit.ENABLE = 1;
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while (adc->STATUS.bit.SYNCBUSY) {
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}
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#elif defined(MCU_SAMD51)
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// Configuration SAMD51
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// Enable APBD clocks and PCHCTRL clocks; GCLK2 at 48 MHz
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if (self->adc_config.device == 0) {
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GCLK->PCHCTRL[ADC0_GCLK_ID].reg = GCLK_PCHCTRL_GEN_GCLK2 | GCLK_PCHCTRL_CHEN;
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MCLK->APBDMASK.bit.ADC0_ = 1;
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} else {
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GCLK->PCHCTRL[ADC1_GCLK_ID].reg = GCLK_PCHCTRL_GEN_GCLK2 | GCLK_PCHCTRL_CHEN;
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MCLK->APBDMASK.bit.ADC1_ = 1;
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}
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// Reset ADC registers
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adc->CTRLA.bit.SWRST = 1;
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while (adc->CTRLA.bit.SWRST) {
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}
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// Get the calibration data
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uint32_t biascomp;
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uint32_t biasr2r;
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uint32_t biasrefbuf;
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if (self->adc_config.device == 0) {
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biascomp = (*((uint32_t *)ADC0_FUSES_BIASCOMP_ADDR) & ADC0_FUSES_BIASCOMP_Msk) >> ADC0_FUSES_BIASCOMP_Pos;
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biasr2r = (*((uint32_t *)ADC0_FUSES_BIASR2R_ADDR) & ADC0_FUSES_BIASR2R_Msk) >> ADC0_FUSES_BIASR2R_Pos;
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biasrefbuf = (*((uint32_t *)ADC0_FUSES_BIASREFBUF_ADDR) & ADC0_FUSES_BIASREFBUF_Msk) >> ADC0_FUSES_BIASREFBUF_Pos;
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} else {
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biascomp = (*((uint32_t *)ADC1_FUSES_BIASCOMP_ADDR) & ADC1_FUSES_BIASCOMP_Msk) >> ADC1_FUSES_BIASCOMP_Pos;
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biasr2r = (*((uint32_t *)ADC1_FUSES_BIASR2R_ADDR) & ADC1_FUSES_BIASR2R_Msk) >> ADC1_FUSES_BIASR2R_Pos;
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biasrefbuf = (*((uint32_t *)ADC1_FUSES_BIASREFBUF_ADDR) & ADC1_FUSES_BIASREFBUF_Msk) >> ADC1_FUSES_BIASREFBUF_Pos;
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}
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/* Write the calibration data. */
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adc->CALIB.reg = ADC_CALIB_BIASCOMP(biascomp) | ADC_CALIB_BIASR2R(biasr2r) | ADC_CALIB_BIASREFBUF(biasrefbuf);
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// Divide 48MHz clock by 32 to obtain 1.5 MHz clock to adc
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adc->CTRLA.reg = ADC_CTRLA_PRESCALER_DIV32;
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// Select external AREFA as reference voltage.
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adc->REFCTRL.reg = ADC_REFCTRL_REFSEL_AREFA;
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// Average: Accumulate samples and scale them down accordingly
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adc->AVGCTRL.reg = self->avg | ADC_AVGCTRL_ADJRES(self->avg);
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// Enable ADC and wait to be ready
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adc->CTRLA.bit.ENABLE = 1;
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while (adc->SYNCBUSY.bit.ENABLE) {
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}
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#endif
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}
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// Set the port as given in self->id as ADC
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mp_hal_set_pin_mux(self->id, ALT_FCT_ADC);
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}
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