qmk_firmware

QMK firmware for my keyboards (Corne, Sweep Ferris) and trackball (Ploopy Adept)
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sym_defer_pk.c (4867B)

      1 // Copyright 2017 Alex Ong<the.onga@gmail.com>
      2 // Copyright 2020 Andrei Purdea<andrei@purdea.ro>
      3 // Copyright 2021 Simon Arlott
      4 // SPDX-License-Identifier: GPL-2.0-or-later
      5 //
      6 // Basic symmetric per-key algorithm. Uses an 8-bit counter per key.
      7 // When no state changes have occured for DEBOUNCE milliseconds, we push the state.
      8 
      9 #include "debounce.h"
     10 #include "timer.h"
     11 #include "util.h"
     12 
     13 #ifndef DEBOUNCE
     14 #    define DEBOUNCE 5
     15 #endif
     16 
     17 // Maximum debounce: 255ms
     18 #if DEBOUNCE > UINT8_MAX
     19 #    undef DEBOUNCE
     20 #    define DEBOUNCE UINT8_MAX
     21 #endif
     22 
     23 #define DEBOUNCE_ELAPSED 0
     24 
     25 #if DEBOUNCE > 0
     26 typedef uint8_t debounce_counter_t;
     27 // Uses MATRIX_ROWS_PER_HAND instead of MATRIX_ROWS to support split keyboards
     28 static debounce_counter_t debounce_counters[MATRIX_ROWS_PER_HAND * MATRIX_COLS] = {DEBOUNCE_ELAPSED};
     29 static bool               counters_need_update;
     30 static bool               cooked_changed;
     31 
     32 static inline void update_debounce_counters_and_transfer_if_expired(matrix_row_t raw[], matrix_row_t cooked[], uint8_t elapsed_time);
     33 static inline void start_debounce_counters(matrix_row_t raw[], matrix_row_t cooked[]);
     34 
     35 void debounce_init(void) {}
     36 
     37 bool debounce(matrix_row_t raw[], matrix_row_t cooked[], bool changed) {
     38     static fast_timer_t last_time;
     39     bool                updated_last = false;
     40     cooked_changed                   = false;
     41 
     42     if (counters_need_update) {
     43         fast_timer_t now          = timer_read_fast();
     44         fast_timer_t elapsed_time = TIMER_DIFF_FAST(now, last_time);
     45 
     46         last_time    = now;
     47         updated_last = true;
     48 
     49         if (elapsed_time > 0) {
     50             // Update debounce counters with elapsed timer clamped to UINT8_MAX
     51             update_debounce_counters_and_transfer_if_expired(raw, cooked, MIN(elapsed_time, UINT8_MAX));
     52         }
     53     }
     54 
     55     if (changed) {
     56         if (!updated_last) {
     57             last_time = timer_read_fast();
     58         }
     59 
     60         start_debounce_counters(raw, cooked);
     61     }
     62 
     63     return cooked_changed;
     64 }
     65 
     66 /**
     67  * @brief Updates debounce counters and transfers debounced key states if the debounce period has expired.
     68  *
     69  * Iterates through each key in the matrix and checks its debounce counter. If the debounce period has expired
     70  * for a key, the debounced state is updated to match the raw state. Otherwise, the debounce counter is decremented
     71  * by the elapsed time and marked for further updates.
     72  *
     73  * @param raw The current raw key state matrix.
     74  * @param cooked The debounced key state matrix to be updated.
     75  * @param elapsed_time The time elapsed since the last debounce update, in milliseconds.
     76  */
     77 static inline void update_debounce_counters_and_transfer_if_expired(matrix_row_t raw[], matrix_row_t cooked[], uint8_t elapsed_time) {
     78     counters_need_update = false;
     79     for (uint8_t row = 0; row < MATRIX_ROWS_PER_HAND; row++) {
     80         uint16_t row_offset = row * MATRIX_COLS;
     81 
     82         for (uint8_t col = 0; col < MATRIX_COLS; col++) {
     83             uint16_t index = row_offset + col;
     84 
     85             if (debounce_counters[index] != DEBOUNCE_ELAPSED) {
     86                 if (debounce_counters[index] <= elapsed_time) {
     87                     debounce_counters[index] = DEBOUNCE_ELAPSED;
     88                     matrix_row_t col_mask    = (MATRIX_ROW_SHIFTER << col);
     89                     matrix_row_t cooked_next = (cooked[row] & ~col_mask) | (raw[row] & col_mask);
     90                     cooked_changed |= cooked[row] ^ cooked_next;
     91                     cooked[row] = cooked_next;
     92                 } else {
     93                     debounce_counters[index] -= elapsed_time;
     94                     counters_need_update = true;
     95                 }
     96             }
     97         }
     98     }
     99 }
    100 
    101 /**
    102  * @brief Initializes debounce counters for keys with changed states.
    103  *
    104  * For each key in the matrix, this function checks if the raw state differs from the debounced state.
    105  * If a change is detected and the debounce counter has elapsed, the counter is set to the debounce period
    106  * and marked for update. Otherwise, the counter is cleared.
    107  *
    108  * @param raw The current raw key state matrix.
    109  * @param cooked The debounced key state matrix.
    110  */
    111 static inline void start_debounce_counters(matrix_row_t raw[], matrix_row_t cooked[]) {
    112     for (uint8_t row = 0; row < MATRIX_ROWS_PER_HAND; row++) {
    113         uint16_t     row_offset = row * MATRIX_COLS;
    114         matrix_row_t delta      = raw[row] ^ cooked[row];
    115 
    116         for (uint8_t col = 0; col < MATRIX_COLS; col++) {
    117             uint16_t index = row_offset + col;
    118 
    119             if (delta & (MATRIX_ROW_SHIFTER << col)) {
    120                 if (debounce_counters[index] == DEBOUNCE_ELAPSED) {
    121                     debounce_counters[index] = DEBOUNCE;
    122                     counters_need_update     = true;
    123                 }
    124             } else {
    125                 debounce_counters[index] = DEBOUNCE_ELAPSED;
    126             }
    127         }
    128     }
    129 }
    130 
    131 #else
    132 #    include "none.c"
    133 #endif