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qmk_firmware

custom branch of QMK firmware git clone https://anongit.hacktivis.me/git/qmk_firmware.git

opt_encoder_tiny.c (4001B)

    

  1. /* Copyright 2023 Leorize <leorize+oss@disroot.org>
  2.  * Copyright 2011 Ben Buxton <bb@cactii.net>
  3.  *
  4.  * This program is free software: you can redistribute it and/or modify
  5.  * it under the terms of the GNU General Public License as published by
  6.  * the Free Software Foundation, either version 3 of the License, or
  7.  * (at your option) any later version.
  8.  *
  9.  * This program is distributed in the hope that it will be useful,
  10.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12.  * GNU General Public License for more details.
  13.  *
  14.  * You should have received a copy of the GNU General Public License
  15.  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16.  */
  17. #include "opt_encoder.h"
  18. #include <stdbool.h>
  19. #include <stdint.h>
  21. /* An extremely simple implementation of the encoder:
  22.  *
  23.  * For read out, the mechanism mimics that of a Schmitt trigger, with
  24.  * statically defined high/low thresholds used instead of computing
  25.  * one at runtime.
  26.  *
  27.  * The advantage of this approach is computing less in the decoder
  28.  * implementation and allow the state to be measured before the wheel
  29.  * moved.
  30.  *
  31.  * Compared to opt_encoder_simple.c, the use of an intermediary state
  32.  * reduces sensitivity and de-sensitize against tiny movements caused
  33.  * when lifting finger off the wheel.
  34.  *
  35.  * For turning decoded values into rotation, an algorithm inspired by
  36.  * http://www.buxtronix.net/2011/10/rotary-encoders-done-properly.html
  37.  * is employed.
  38.  */
  40. #if !defined(ENCODER_LOW_THRES_A) || !defined(ENCODER_HIGH_THRES_A)
  41. #    error "The thresholds for phototransistors A is not defined in config.h"
  42. #endif
  43. #if !defined(ENCODER_LOW_THRES_B) || !defined(ENCODER_HIGH_THRES_B)
  44. #    error "The thresholds for phototransistors B is not defined in config.h"
  45. #endif
  46. /*
  47.  * Sample values, captured for a Ploopy Mini Trackball
  48.  *
  49.  * The following min-max values was captured by aggregating data recorded
  50.  * when debug_encoder is enabled:
  51.  *
  52.  *   A: min: 0, max: 214
  53.  *   B: min: 0, max: 204
  54.  *
  55.  * The threshold specified is then defined at the 1/4 and the 3/4 points.
  56.  *
  57.  * As these values might vary between units, you're encouraged to
  58.  * measure your own.
  59.  */
  60. #if 0
  61. #    define ENCODER_LOW_THRES_A 53
  62. #    define ENCODER_HIGH_THRES_A 161
  63. #    define ENCODER_LOW_THRES_B 52
  64. #    define ENCODER_HIGH_THRES_B 153
  65. #endif
  67. /* Utilities for composing the encoder state */
  68. #define MAKE_STATE(HI_A, HI_B) (((uint8_t)((HI_A) & 0x1) << 1) | ((uint8_t)((HI_B) & 0x1)))
  69. #define STATE_A(st) ((st & 0x2) >> 1)
  70. #define STATE_B(st) (st & 0x1)
  72. typedef enum {
  73.     START,
  74.     DOWN_BEGIN,
  75.     UP_BEGIN,
  76.     START_MID,
  77.     DOWN_BEGIN_MID,
  78.     UP_BEGIN_MID,
  79.     STATE_MASK    = 0xf, /* 0b1111 */
  80.     EMIT_UP       = 0x10,
  81.     EMIT_UP_MID   = EMIT_UP & START_MID,
  82.     EMIT_DOWN     = 0x80,
  83.     EMIT_DOWN_MID = EMIT_DOWN & START_MID,
  84.     EMIT_MASK     = 0xf0
  85. } encoder_state_t;
  87. static encoder_state_t state;
  88. static uint8_t         encState;
  90. static const uint8_t transitions[] = {
  91.     // clang-format off
  92.     // START -> 00, 01, 10, 11
  93.     START, DOWN_BEGIN, UP_BEGIN, START_MID,
  94.     // DOWN_BEGIN -> 00, 01, 10, 11
  95.     START, DOWN_BEGIN, START, EMIT_DOWN_MID,
  96.     // UP_BEGIN -> 00, 01, 10, 11
  97.     START, START, UP_BEGIN, EMIT_UP_MID,
  98.     // START_MID -> 00, 01, 10, 11
  99.     START, UP_BEGIN_MID, DOWN_BEGIN_MID, START_MID,
  100.     // DOWN_BEGIN_MID -> 00, 01, 10, 11
  101.     EMIT_DOWN, START_MID, DOWN_BEGIN_MID, START_MID,
  102.     // UP_BEGIN_MID -> 00, 01, 10, 11
  103.     EMIT_UP, UP_BEGIN_MID, START_MID, START_MID,
  104.     // clang-format on
  105. };
  107. void opt_encoder_init(void) {
  108.     state    = START;
  109.     encState = 0;
  110. }
  112. int8_t opt_encoder_handler(uint16_t encA, uint16_t encB) {
  113.     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));
  114.     state    = transitions[((state & STATE_MASK) << 2) + encState];
  115.     return state & EMIT_MASK;
  116. }