mirror of
https://github.com/qmk/qmk_firmware.git
synced 2024-11-25 12:46:41 +00:00
117 lines
3.9 KiB
C
117 lines
3.9 KiB
C
/* Copyright 2023 Leorize <leorize+oss@disroot.org>
|
|
* Copyright 2011 Ben Buxton <bb@cactii.net>
|
|
*
|
|
* This program is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#include "opt_encoder.h"
|
|
#include <stdbool.h>
|
|
#include <stdint.h>
|
|
|
|
/* An extremely simple implementation of the encoder:
|
|
*
|
|
* For read out, the mechanism mimics that of a Schmitt trigger, with
|
|
* statically defined high/low thresholds used instead of computing
|
|
* one at runtime.
|
|
*
|
|
* The advantage of this approach is computing less in the decoder
|
|
* implementation and allow the state to be measured before the wheel
|
|
* moved.
|
|
*
|
|
* Compared to opt_encoder_simple.c, the use of an intermediary state
|
|
* reduces sensitivity and de-sensitize against tiny movements caused
|
|
* when lifting finger off the wheel.
|
|
*
|
|
* For turning decoded values into rotation, an algorithm inspired by
|
|
* http://www.buxtronix.net/2011/10/rotary-encoders-done-properly.html
|
|
* is employed.
|
|
*/
|
|
|
|
#if !defined(ENCODER_LOW_THRES_A) || !defined(ENCODER_HIGH_THRES_A)
|
|
# error "The thresholds for phototransistors A is not defined in config.h"
|
|
#endif
|
|
#if !defined(ENCODER_LOW_THRES_B) || !defined(ENCODER_HIGH_THRES_B)
|
|
# error "The thresholds for phototransistors B is not defined in config.h"
|
|
#endif
|
|
/*
|
|
* Sample values, captured for a Ploopy Mini Trackball
|
|
*
|
|
* The following min-max values was captured by aggregating data recorded
|
|
* when debug_encoder is enabled:
|
|
*
|
|
* A: min: 0, max: 214
|
|
* B: min: 0, max: 204
|
|
*
|
|
* The threshold specified is then defined at the 1/4 and the 3/4 points.
|
|
*
|
|
* As these values might vary between units, you're encouraged to
|
|
* measure your own.
|
|
*/
|
|
#if 0
|
|
# define ENCODER_LOW_THRES_A 53
|
|
# define ENCODER_HIGH_THRES_A 161
|
|
# define ENCODER_LOW_THRES_B 52
|
|
# define ENCODER_HIGH_THRES_B 153
|
|
#endif
|
|
|
|
/* Utilities for composing the encoder state */
|
|
#define MAKE_STATE(HI_A, HI_B) (((uint8_t)((HI_A) & 0x1) << 1) | ((uint8_t)((HI_B) & 0x1)))
|
|
#define STATE_A(st) ((st & 0x2) >> 1)
|
|
#define STATE_B(st) (st & 0x1)
|
|
|
|
typedef enum {
|
|
START,
|
|
DOWN_BEGIN,
|
|
UP_BEGIN,
|
|
START_MID,
|
|
DOWN_BEGIN_MID,
|
|
UP_BEGIN_MID,
|
|
STATE_MASK = 0xf, /* 0b1111 */
|
|
EMIT_UP = 0x10,
|
|
EMIT_UP_MID = EMIT_UP & START_MID,
|
|
EMIT_DOWN = 0x80,
|
|
EMIT_DOWN_MID = EMIT_DOWN & START_MID,
|
|
EMIT_MASK = 0xf0
|
|
} encoder_state_t;
|
|
|
|
static encoder_state_t state;
|
|
static uint8_t encState;
|
|
|
|
static const uint8_t transitions[] = {
|
|
// clang-format off
|
|
// START -> 00, 01, 10, 11
|
|
START, DOWN_BEGIN, UP_BEGIN, START_MID,
|
|
// DOWN_BEGIN -> 00, 01, 10, 11
|
|
START, DOWN_BEGIN, START, EMIT_DOWN_MID,
|
|
// UP_BEGIN -> 00, 01, 10, 11
|
|
START, START, UP_BEGIN, EMIT_UP_MID,
|
|
// START_MID -> 00, 01, 10, 11
|
|
START, UP_BEGIN_MID, DOWN_BEGIN_MID, START_MID,
|
|
// DOWN_BEGIN_MID -> 00, 01, 10, 11
|
|
EMIT_DOWN, START_MID, DOWN_BEGIN_MID, START_MID,
|
|
// UP_BEGIN_MID -> 00, 01, 10, 11
|
|
EMIT_UP, UP_BEGIN_MID, START_MID, START_MID,
|
|
// clang-format on
|
|
};
|
|
|
|
void opt_encoder_init(void) {
|
|
state = START;
|
|
encState = 0;
|
|
}
|
|
|
|
int8_t opt_encoder_handler(uint16_t encA, uint16_t encB) {
|
|
encState = MAKE_STATE((STATE_A(encState) & (encA > ENCODER_LOW_THRES_A)) | (encA > ENCODER_HIGH_THRES_A), (STATE_B(encState) & (encB > ENCODER_LOW_THRES_B)) | (encB > ENCODER_HIGH_THRES_B));
|
|
state = transitions[((state & STATE_MASK) << 2) + encState];
|
|
return state & EMIT_MASK;
|
|
}
|