sym_defer_pr.c (4121B)
1 // Copyright 2017 Alex Ong<the.onga@gmail.com> 2 // Copyright 2020 Andrei Purdea<andrei@purdea.ro> 3 // Copyright 2021 Simon Arlott 4 // Copyright @filterpaper 5 // SPDX-License-Identifier: GPL-2.0-or-later 6 // 7 // Basic symmetric per-row algorithm. Uses an 8-bit counter per row. 8 // When no state changes have occured for DEBOUNCE milliseconds, we push the state. 9 10 #include "debounce.h" 11 #include "timer.h" 12 #include "util.h" 13 14 #ifndef DEBOUNCE 15 # define DEBOUNCE 5 16 #endif 17 18 // Maximum debounce: 255ms 19 #if DEBOUNCE > UINT8_MAX 20 # undef DEBOUNCE 21 # define DEBOUNCE UINT8_MAX 22 #endif 23 24 #define DEBOUNCE_ELAPSED 0 25 26 #if DEBOUNCE > 0 27 typedef uint8_t debounce_counter_t; 28 // Uses MATRIX_ROWS_PER_HAND instead of MATRIX_ROWS to support split keyboards 29 static debounce_counter_t debounce_counters[MATRIX_ROWS_PER_HAND] = {DEBOUNCE_ELAPSED}; 30 static bool counters_need_update; 31 static bool cooked_changed; 32 33 static inline void update_debounce_counters_and_transfer_if_expired(matrix_row_t raw[], matrix_row_t cooked[], uint8_t elapsed_time); 34 static inline void start_debounce_counters(matrix_row_t raw[], matrix_row_t cooked[]); 35 36 void debounce_init(void) {} 37 38 bool debounce(matrix_row_t raw[], matrix_row_t cooked[], bool changed) { 39 static fast_timer_t last_time; 40 bool updated_last = false; 41 cooked_changed = false; 42 43 if (counters_need_update) { 44 fast_timer_t now = timer_read_fast(); 45 fast_timer_t elapsed_time = TIMER_DIFF_FAST(now, last_time); 46 47 last_time = now; 48 updated_last = true; 49 50 if (elapsed_time > 0) { 51 // Update debounce counters with elapsed timer clamped to UINT8_MAX 52 update_debounce_counters_and_transfer_if_expired(raw, cooked, MIN(elapsed_time, UINT8_MAX)); 53 } 54 } 55 56 if (changed) { 57 if (!updated_last) { 58 last_time = timer_read_fast(); 59 } 60 61 start_debounce_counters(raw, cooked); 62 } 63 64 return cooked_changed; 65 } 66 67 /** 68 * @brief Updates debounce counters and transfers debounced row states if the debounce period has expired. 69 * 70 * Iterates through each row in the matrix and checks its debounce counter. If the debounce period has expired 71 * for a row, the debounced state is updated to match the raw state. Otherwise, the debounce counter is decremented 72 * by the elapsed time and marked for further updates. 73 * 74 * @param raw The current raw key state matrix. 75 * @param cooked The debounced key state matrix to be updated. 76 * @param elapsed_time The time elapsed since the last debounce update, in milliseconds. 77 */ 78 static inline void update_debounce_counters_and_transfer_if_expired(matrix_row_t raw[], matrix_row_t cooked[], uint8_t elapsed_time) { 79 counters_need_update = false; 80 for (uint8_t row = 0; row < MATRIX_ROWS_PER_HAND; row++) { 81 if (debounce_counters[row] != DEBOUNCE_ELAPSED) { 82 if (debounce_counters[row] <= elapsed_time) { 83 debounce_counters[row] = DEBOUNCE_ELAPSED; 84 cooked_changed |= cooked[row] ^ raw[row]; 85 cooked[row] = raw[row]; 86 } else { 87 debounce_counters[row] -= elapsed_time; 88 counters_need_update = true; 89 } 90 } 91 } 92 } 93 94 /** 95 * @brief Initializes debounce counters for rows with changed states. 96 * 97 * For each row in the matrix, this function checks if the raw state differs from the debounced state. 98 * If a change is detected and the debounce counter has elapsed, the counter is set to the debounce period 99 * and marked for update. Otherwise, the counter is cleared. 100 * 101 * @param raw The current raw key state matrix. 102 * @param cooked The debounced key state matrix. 103 */ 104 static inline void start_debounce_counters(matrix_row_t raw[], matrix_row_t cooked[]) { 105 for (uint8_t row = 0; row < MATRIX_ROWS_PER_HAND; row++) { 106 if (raw[row] != cooked[row]) { 107 debounce_counters[row] = DEBOUNCE; 108 counters_need_update = true; 109 } else { 110 debounce_counters[row] = DEBOUNCE_ELAPSED; 111 } 112 } 113 } 114 115 #else 116 # include "none.c" 117 #endif