circuitpython/ports/nrf/common-hal/rotaryio/IncrementalEncoder.c

117 lines
4.0 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Nick Moore 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 "common-hal/rotaryio/IncrementalEncoder.h"
#include "nrfx_gpiote.h"
#include "py/runtime.h"
#include <stdio.h>
// obj array to map pin number -> self since nrfx hide the mapping
static rotaryio_incrementalencoder_obj_t *_objs[NUMBER_OF_PINS];
static void _intr_handler(nrfx_gpiote_pin_t pin, nrf_gpiote_polarity_t action) {
rotaryio_incrementalencoder_obj_t *self = _objs[pin];
if (!self) return;
// reads a state 0 .. 3 *in order*.
uint8_t new_state = nrf_gpio_pin_read(self->pin_a);
new_state = (new_state << 1) + (new_state ^ nrf_gpio_pin_read(self->pin_b));
uint8_t change = (new_state - self->state) & 0x03;
if (change == 1) self->quarter++;
else if (change == 3) self->quarter--;
// ignore other state transitions
self->state = new_state;
// logic from the atmel-samd port: provides some damping and scales movement
// down by 4:1.
if (self->quarter >= 4) {
self->position++;
self->quarter = 0;
} else if (self->quarter <= -4) {
self->position--;
self->quarter = 0;
}
}
void common_hal_rotaryio_incrementalencoder_construct(rotaryio_incrementalencoder_obj_t* self,
const mcu_pin_obj_t* pin_a, const mcu_pin_obj_t* pin_b) {
self->pin_a = pin_a->number;
self->pin_b = pin_b->number;
_objs[self->pin_a] = self;
_objs[self->pin_b] = self;
nrfx_gpiote_in_config_t cfg = {
.sense = NRF_GPIOTE_POLARITY_TOGGLE,
.pull = NRF_GPIO_PIN_PULLUP,
.is_watcher = false,
.hi_accuracy = true,
.skip_gpio_setup = false
};
nrfx_gpiote_in_init(self->pin_a, &cfg, _intr_handler);
nrfx_gpiote_in_init(self->pin_b, &cfg, _intr_handler);
nrfx_gpiote_in_event_enable(self->pin_a, true);
nrfx_gpiote_in_event_enable(self->pin_b, true);
claim_pin(pin_a);
claim_pin(pin_b);
}
bool common_hal_rotaryio_incrementalencoder_deinited(rotaryio_incrementalencoder_obj_t* self) {
return self->pin_a == NO_PIN;
}
void common_hal_rotaryio_incrementalencoder_deinit(rotaryio_incrementalencoder_obj_t* self) {
if (common_hal_rotaryio_incrementalencoder_deinited(self)) {
return;
}
_objs[self->pin_a] = NULL;
_objs[self->pin_b] = NULL;
nrfx_gpiote_in_event_disable(self->pin_a);
nrfx_gpiote_in_event_disable(self->pin_b);
nrfx_gpiote_in_uninit(self->pin_a);
nrfx_gpiote_in_uninit(self->pin_b);
reset_pin_number(self->pin_a);
reset_pin_number(self->pin_b);
self->pin_a = NO_PIN;
self->pin_b = NO_PIN;
}
mp_int_t common_hal_rotaryio_incrementalencoder_get_position(rotaryio_incrementalencoder_obj_t* self) {
return self->position;
}
void common_hal_rotaryio_incrementalencoder_set_position(rotaryio_incrementalencoder_obj_t* self,
mp_int_t new_position) {
self->position = new_position;
}