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micropython/ports/nrf/modules/machine/adc.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2017-2018 Glenn Ruben Bakke
*
* 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 <stdio.h>
#include <string.h>
#include "py/nlr.h"
#include "py/runtime.h"
#include "py/mphal.h"
#if MICROPY_PY_MACHINE_ADC
#include "adc.h"
#if NRF51
#include "nrfx_adc.h"
#else
#include "nrfx_saadc.h"
#endif
typedef struct _machine_adc_obj_t {
mp_obj_base_t base;
uint8_t id;
#if NRF51
uint8_t ain;
#endif
} machine_adc_obj_t;
STATIC const machine_adc_obj_t machine_adc_obj[] = {
#if NRF51
{{&machine_adc_type}, .id = 0, .ain = NRF_ADC_CONFIG_INPUT_0},
{{&machine_adc_type}, .id = 1, .ain = NRF_ADC_CONFIG_INPUT_1},
{{&machine_adc_type}, .id = 2, .ain = NRF_ADC_CONFIG_INPUT_2},
{{&machine_adc_type}, .id = 3, .ain = NRF_ADC_CONFIG_INPUT_3},
{{&machine_adc_type}, .id = 4, .ain = NRF_ADC_CONFIG_INPUT_4},
{{&machine_adc_type}, .id = 5, .ain = NRF_ADC_CONFIG_INPUT_5},
{{&machine_adc_type}, .id = 6, .ain = NRF_ADC_CONFIG_INPUT_6},
{{&machine_adc_type}, .id = 7, .ain = NRF_ADC_CONFIG_INPUT_7},
#else
{{&machine_adc_type}, .id = 0},
{{&machine_adc_type}, .id = 1},
{{&machine_adc_type}, .id = 2},
{{&machine_adc_type}, .id = 3},
{{&machine_adc_type}, .id = 4},
{{&machine_adc_type}, .id = 5},
{{&machine_adc_type}, .id = 6},
{{&machine_adc_type}, .id = 7},
#endif
};
void adc_init0(void) {
#if defined(NRF52_SERIES)
const uint8_t interrupt_priority = 6;
nrfx_saadc_init(interrupt_priority);
#endif
}
STATIC int adc_find(mp_obj_t id) {
int adc_idx;
if (mp_obj_is_int(id)) {
// Given an integer id
adc_idx = mp_obj_get_int(id);
} else {
// Assume it's a pin-compatible object and convert it to an ADC channel number
mp_hal_pin_obj_t pin = mp_hal_get_pin_obj(id);
if (pin->adc_num & PIN_ADC1) {
adc_idx = pin->adc_channel;
} else {
mp_raise_ValueError(MP_ERROR_TEXT("invalid Pin for ADC"));
}
}
if (adc_idx >= 0 && adc_idx < MP_ARRAY_SIZE(machine_adc_obj)
&& machine_adc_obj[adc_idx].id != (uint8_t)-1) {
return adc_idx;
}
mp_raise_ValueError(MP_ERROR_TEXT("ADC doesn't exist"));
}
/// \method __str__()
/// Return a string describing the ADC object.
STATIC void machine_adc_print(const mp_print_t *print, mp_obj_t o, mp_print_kind_t kind) {
machine_adc_obj_t *self = o;
mp_printf(print, "ADC(%u)", self->id);
}
/******************************************************************************/
/* MicroPython bindings for machine API */
// for make_new
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) {
enum { ARG_id };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_id, MP_ARG_OBJ, {.u_obj = MP_OBJ_NEW_SMALL_INT(-1) } },
};
// parse args
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
int adc_id = adc_find(args[ARG_id].u_obj);
const machine_adc_obj_t *self = &machine_adc_obj[adc_id];
#if defined(NRF52_SERIES)
const nrfx_saadc_channel_t config = { \
.channel_config =
{
.resistor_p = NRF_SAADC_RESISTOR_DISABLED,
.resistor_n = NRF_SAADC_RESISTOR_DISABLED,
.gain = NRF_SAADC_GAIN1_4,
.reference = NRF_SAADC_REFERENCE_VDD4,
.acq_time = NRF_SAADC_ACQTIME_3US,
.mode = NRF_SAADC_MODE_SINGLE_ENDED,
.burst = NRF_SAADC_BURST_DISABLED,
},
.pin_p = (nrf_saadc_input_t)(1 + self->id), // pin_p=0 is AIN0, pin_p=8 is AIN7
.pin_n = NRF_SAADC_INPUT_DISABLED,
.channel_index = self->id,
};
nrfx_saadc_channels_config(&config, 1);
#endif
return MP_OBJ_FROM_PTR(self);
}
int16_t machine_adc_value_read(machine_adc_obj_t * adc_obj) {
#if NRF51
nrf_adc_value_t value = 0;
nrfx_adc_channel_t channel_config = {
.config.resolution = NRF_ADC_CONFIG_RES_8BIT,
.config.input = NRF_ADC_CONFIG_SCALING_INPUT_TWO_THIRDS,
.config.reference = NRF_ADC_CONFIG_REF_VBG,
.config.input = adc_obj->ain,
.config.extref = ADC_CONFIG_EXTREFSEL_None << ADC_CONFIG_EXTREFSEL_Pos // Currently not defined in nrfx/hal.
};
nrfx_adc_sample_convert(&channel_config, &value);
#else // NRF52
nrf_saadc_value_t value = 0;
nrfx_saadc_simple_mode_set((1 << adc_obj->id), NRF_SAADC_RESOLUTION_8BIT, NRF_SAADC_INPUT_DISABLED, NULL);
nrfx_saadc_buffer_set(&value, 1);
nrfx_saadc_mode_trigger();
#endif
return value;
}
// read_u16()
STATIC mp_obj_t machine_adc_read_u16(mp_obj_t self_in) {
machine_adc_obj_t *self = self_in;
int16_t raw = machine_adc_value_read(self);
#if defined(NRF52_SERIES)
// raw is signed but the channel is in single-ended mode and this method cannot return negative values
if (raw < 0) {
raw = 0;
}
#endif
// raw is an 8-bit value
return MP_OBJ_NEW_SMALL_INT(raw << 8 | raw);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_machine_adc_read_u16_obj, machine_adc_read_u16);
/// \method value()
/// Read adc level.
mp_obj_t machine_adc_value(mp_obj_t self_in) {
machine_adc_obj_t *self = self_in;
int16_t value = machine_adc_value_read(self);
return MP_OBJ_NEW_SMALL_INT(value);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(mp_machine_adc_value_obj, machine_adc_value);
#if NRF51
#define ADC_REF_VOLTAGE_IN_MILLIVOLT (1200) // Reference voltage in mV (1.2V).
#define ADC_PRE_SCALING_MULTIPLIER (3) // VDD 1/3 prescaling as input. Hence, multiplied by 3 to get the value of the battery voltage.
#else // NRF52
#define ADC_REF_VOLTAGE_IN_MILLIVOLT (600) // Reference voltage in mV (0.6V).
#define ADC_PRE_SCALING_MULTIPLIER (6) // VDD 1/6 prescaling as input. Hence, multiplied by 6 to get the value of the battery voltage.
#endif
#define DIODE_VOLT_DROP_MILLIVOLT (270) // Voltage drop over diode.
#define BATTERY_MILLIVOLT(VALUE) \
((((VALUE) * ADC_REF_VOLTAGE_IN_MILLIVOLT) / 255) * ADC_PRE_SCALING_MULTIPLIER)
static uint8_t battery_level_in_percent(const uint16_t mvolts)
{
uint8_t battery_level;
if (mvolts >= 3000) {
battery_level = 100;
} else if (mvolts > 2900) {
battery_level = 100 - ((3000 - mvolts) * 58) / 100;
} else if (mvolts > 2740) {
battery_level = 42 - ((2900 - mvolts) * 24) / 160;
} else if (mvolts > 2440) {
battery_level = 18 - ((2740 - mvolts) * 12) / 300;
} else if (mvolts > 2100) {
battery_level = 6 - ((2440 - mvolts) * 6) / 340;
} else {
battery_level = 0;
}
return battery_level;
}
/// \method battery_level()
/// Get battery level in percentage.
mp_obj_t machine_adc_battery_level(void) {
#if NRF51
nrf_adc_value_t value = 0;
nrfx_adc_channel_t channel_config = {
.config.resolution = NRF_ADC_CONFIG_RES_8BIT,
.config.input = NRF_ADC_CONFIG_SCALING_SUPPLY_ONE_THIRD,
.config.reference = NRF_ADC_CONFIG_REF_VBG,
.config.input = NRF_ADC_CONFIG_INPUT_DISABLED,
.config.extref = ADC_CONFIG_EXTREFSEL_None << ADC_CONFIG_EXTREFSEL_Pos // Currently not defined in nrfx/hal.
};
nrfx_adc_sample_convert(&channel_config, &value);
#else // NRF52
nrf_saadc_value_t value = 0;
const nrfx_saadc_channel_t config = { \
.channel_config =
{
.resistor_p = NRF_SAADC_RESISTOR_DISABLED,
.resistor_n = NRF_SAADC_RESISTOR_DISABLED,
.gain = NRF_SAADC_GAIN1_6,
.reference = NRF_SAADC_REFERENCE_INTERNAL,
.acq_time = NRF_SAADC_ACQTIME_3US,
.mode = NRF_SAADC_MODE_SINGLE_ENDED,
.burst = NRF_SAADC_BURST_DISABLED,
},
.pin_p = NRF_SAADC_INPUT_VDD,
.pin_n = NRF_SAADC_INPUT_DISABLED,
.channel_index = 0,
};
nrfx_saadc_channels_config(&config, 1);
nrfx_saadc_simple_mode_set((1 << 0), NRF_SAADC_RESOLUTION_8BIT, NRF_SAADC_INPUT_DISABLED, NULL);
nrfx_saadc_buffer_set(&value, 1);
nrfx_saadc_mode_trigger();
#endif
uint16_t batt_lvl_in_milli_volts = BATTERY_MILLIVOLT(value) + DIODE_VOLT_DROP_MILLIVOLT;
uint16_t batt_in_percent = battery_level_in_percent(batt_lvl_in_milli_volts);
return MP_OBJ_NEW_SMALL_INT(batt_in_percent);
}
STATIC MP_DEFINE_CONST_FUN_OBJ_0(mp_machine_adc_battery_level_obj, machine_adc_battery_level);
STATIC const mp_rom_map_elem_t machine_adc_locals_dict_table[] = {
// instance methods
{ MP_ROM_QSTR(MP_QSTR_read_u16), MP_ROM_PTR(&mp_machine_adc_read_u16_obj) },
{ MP_ROM_QSTR(MP_QSTR_value), MP_ROM_PTR(&mp_machine_adc_value_obj) },
// class methods
{ MP_ROM_QSTR(MP_QSTR_battery_level), MP_ROM_PTR(&mp_machine_adc_battery_level_obj) },
};
STATIC MP_DEFINE_CONST_DICT(machine_adc_locals_dict, machine_adc_locals_dict_table);
MP_DEFINE_CONST_OBJ_TYPE(
machine_adc_type,
MP_QSTR_ADC,
MP_TYPE_FLAG_NONE,
make_new, machine_adc_make_new,
locals_dict, &machine_adc_locals_dict,
print, machine_adc_print
);
#endif // MICROPY_PY_MACHINE_ADC
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