circuitpython/atmel-samd/common-hal/nativeio/AnalogIn.c
Scott Shawcroft ccbb5e84f9 This introduces an alternative hardware API called nativeio structured around different functions that are typically accelerated by native hardware. Its not meant to reflect the structure of the hardware.
Docs are here: http://tannewt-micropython.readthedocs.io/en/microcontroller/

It differs from upstream's machine in the following ways:

* Python API is identical across ports due to code structure. (Lives in shared-bindings)
* Focuses on abstracting common functionality (AnalogIn) and not representing structure (ADC).
* Documentation lives with code making it easy to ensure they match.
* Pin is split into references (board.D13 and microcontroller.pin.PA17) and functionality (DigitalInOut).
* All nativeio classes claim underlying hardware resources when inited on construction, support Context Managers (aka with statements) and have deinit methods which release the claimed hardware.
* All constructors take pin references rather than peripheral ids. Its up to the implementation to find hardware or throw and exception.
2016-11-21 14:11:52 -08:00

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2.8 KiB
C

/*
* This file is part of the Micro Python project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Scott Shawcroft for Adafruit Industries
*
* 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 <string.h>
#include "py/nlr.h"
#include "py/runtime.h"
#include "py/binary.h"
#include "py/mphal.h"
#include "shared-bindings/nativeio/AnalogIn.h"
#include "asf/sam0/drivers/adc/adc.h"
void common_hal_nativeio_analogin_construct(nativeio_analogin_obj_t* self,
const mcu_pin_obj_t *pin) {
if (!pin->has_adc) {
// No ADC function on that pin
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "pin %q does not have ADC capabilities", pin->name));
}
self->pin = pin;
struct adc_config config_adc;
adc_get_config_defaults(&config_adc);
config_adc.positive_input = self->pin->adc_input;
config_adc.resolution = ADC_RESOLUTION_CUSTOM;
config_adc.accumulate_samples = ADC_ACCUMULATE_SAMPLES_16;
config_adc.divide_result = ADC_DIVIDE_RESULT_16;
config_adc.clock_prescaler = ADC_CLOCK_PRESCALER_DIV128;
adc_init(&self->adc_instance, ADC, &config_adc);
}
// TODO(tannewt): Don't turn it all on just for one read. This simplifies
// handling of reading multiple inputs and surviving sleep though so for now its
// ok.
uint16_t common_hal_nativeio_analogin_get_value(nativeio_analogin_obj_t *self) {
adc_enable(&self->adc_instance);
adc_start_conversion(&self->adc_instance);
uint16_t data;
enum status_code status = adc_read(&self->adc_instance, &data);
while (status == STATUS_BUSY) {
status = adc_read(&self->adc_instance, &data);
}
if (status == STATUS_ERR_OVERFLOW) {
// TODO(tannewt): Throw an error.
}
adc_disable(&self->adc_instance);
return data;
}