85 lines
3.3 KiB
C
85 lines
3.3 KiB
C
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/*
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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 Jeff Epler for Adafruit Industries
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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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#if CIRCUITPY_ROTARYIO && CIRCUITPY_ROTARYIO_SOFTENCODER
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#include "shared-module/rotaryio/IncrementalEncoder.h"
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#include "common-hal/rotaryio/IncrementalEncoder.h"
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void shared_module_softencoder_state_init(rotaryio_incrementalencoder_obj_t *self, uint8_t quiescent_state) {
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self->state = quiescent_state;
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self->quarter_count = 0;
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common_hal_rotaryio_incrementalencoder_set_position(self, 0);
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}
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void shared_module_softencoder_state_update(rotaryio_incrementalencoder_obj_t *self, uint8_t new_state) {
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#define BAD 7
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static const int8_t transitions[16] = {
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0, // 00 -> 00 no movement
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-1, // 00 -> 01 3/4 ccw (11 detent) or 1/4 ccw (00 at detent)
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+1, // 00 -> 10 3/4 cw or 1/4 cw
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BAD, // 00 -> 11 non-Gray-code transition
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+1, // 01 -> 00 2/4 or 4/4 cw
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0, // 01 -> 01 no movement
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BAD, // 01 -> 10 non-Gray-code transition
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-1, // 01 -> 11 4/4 or 2/4 ccw
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-1, // 10 -> 00 2/4 or 4/4 ccw
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BAD, // 10 -> 01 non-Gray-code transition
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0, // 10 -> 10 no movement
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+1, // 10 -> 11 4/4 or 2/4 cw
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BAD, // 11 -> 00 non-Gray-code transition
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+1, // 11 -> 01 1/4 or 3/4 cw
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-1, // 11 -> 10 1/4 or 3/4 ccw
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0, // 11 -> 11 no movement
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};
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new_state &= 0x3;
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int idx = (self->state << 2) | new_state;
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self->state = new_state;
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int8_t quarter_incr = transitions[idx];
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if (quarter_incr == BAD) {
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// Missed a transition. We don't know which way we're going, so do nothing.
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return;
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}
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if (self->quarter_count >= 4) {
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self->position += 1;
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self->quarter_count = 0;
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} else if (self->quarter_count <= -4) {
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self->position -= 1;
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self->quarter_count = 0;
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}
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}
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mp_int_t common_hal_rotaryio_incrementalencoder_get_position(rotaryio_incrementalencoder_obj_t *self) {
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return self->position;
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}
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void common_hal_rotaryio_incrementalencoder_set_position(rotaryio_incrementalencoder_obj_t *self, mp_int_t position) {
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self->position = position;
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}
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#endif
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