circuitpython/ports/mimxrt/machine_adc.c

145 lines
5.0 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2021 Philipp Ebensberger
*
* 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 <stdint.h>
#include "py/obj.h"
#include "py/runtime.h"
#include "py/mphal.h"
#include "fsl_adc.h"
#include "fsl_gpio.h"
#include "fsl_iomuxc.h"
#include "modmachine.h"
typedef struct _machine_adc_obj_t {
mp_obj_base_t base;
ADC_Type *adc;
uint8_t channel;
uint8_t channel_group;
uint16_t resolution;
} machine_adc_obj_t;
STATIC ADC_Type *const adc_bases[] = ADC_BASE_PTRS;
STATIC void adc_obj_print(const mp_print_t *print, mp_obj_t o, mp_print_kind_t kind) {
(void)kind;
machine_adc_obj_t *self = MP_OBJ_TO_PTR(o);
// Get ADC adc id
for (int i = 1; i < sizeof(adc_bases) / sizeof(ADC_Type *); ++i) {
if (adc_bases[i] == self->adc) {
mp_printf(print, "ADC(%u, channel=%u)", i, self->channel);
break;
}
}
}
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 *args) {
mp_arg_check_num(n_args, n_kw, 1, 1, false);
// Unpack and check parameter
const machine_pin_obj_t *pin = pin_find(args[0]);
if (pin->adc_list_len == 0) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("Pin(%q) does not have ADC capabilities"), pin->name);
}
// Extract arguments
ADC_Type *adc_instance = pin->adc_list[0].instance; // NOTE: we only use the first ADC assignment - multiple assignments are not supported for now
uint8_t channel = pin->adc_list[0].channel;
// Configure ADC peripheral channel
adc_channel_config_t channel_config = {
.channelNumber = (uint32_t)channel,
.enableInterruptOnConversionCompleted = false,
};
ADC_SetChannelConfig(adc_instance, 0UL, &channel_config); // NOTE: we always choose channel group '0' since we only perform software triggered conversion
// Create ADC Instance
machine_adc_obj_t *o = mp_obj_malloc(machine_adc_obj_t, &machine_adc_type);
o->adc = adc_instance;
o->channel = (uint8_t)channel;
o->channel_group = 0;
o->resolution = 4096; // NOTE: currently only 12bit resolution supported
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);
// Initiate conversion
adc_channel_config_t channel_config = {
.channelNumber = self->channel,
.enableInterruptOnConversionCompleted = false,
};
ADC_SetChannelConfig(self->adc, (uint32_t)self->channel_group, &channel_config);
// Wait for conversion to finish
while (!ADC_GetChannelStatusFlags(self->adc, (uint32_t)self->channel_group)) {
// do nothing
}
// Measure input voltage
uint32_t value = ADC_GetChannelConversionValue(self->adc, (uint32_t)self->channel_group);
return MP_OBJ_NEW_SMALL_INT(value * 65535 / self->resolution);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_adc_read_u16_obj, machine_adc_read_u16);
STATIC const mp_rom_map_elem_t adc_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_read_u16), MP_ROM_PTR(&machine_adc_read_u16_obj) },
};
STATIC MP_DEFINE_CONST_DICT(adc_locals_dict, adc_locals_dict_table);
const mp_obj_type_t machine_adc_type = {
{&mp_type_type},
.name = MP_QSTR_ADC,
.print = adc_obj_print,
.make_new = adc_obj_make_new,
.locals_dict = (mp_obj_dict_t *)&adc_locals_dict,
};
void machine_adc_init(void) {
for (int i = 1; i < sizeof(adc_bases) / sizeof(ADC_Type *); ++i) {
ADC_Type *adc_instance = adc_bases[i];
// Configure ADC perpheral
adc_config_t config;
ADC_GetDefaultConfig(&config);
ADC_Init(adc_instance, &config);
// Perform calibration
status_t calib_state = ADC_DoAutoCalibration(adc_instance);
if (calib_state == kStatus_Fail) {
mp_printf(&mp_plat_print, "Calibration for ADC Instance %d failed", i);
}
}
}