117 lines
4 KiB
C
117 lines
4 KiB
C
// Copyright 2017 Alex Ong<the.onga@gmail.com>
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// Copyright 2020 Andrei Purdea<andrei@purdea.ro>
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// Copyright 2021 Simon Arlott
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// Copyright @filterpaper
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// SPDX-License-Identifier: GPL-2.0-or-later
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//
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// Basic symmetric per-row algorithm. Uses an 8-bit counter per row.
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// When no state changes have occured for DEBOUNCE milliseconds, we push the state.
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#include "debounce.h"
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#include "timer.h"
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#include "util.h"
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#ifndef DEBOUNCE
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# define DEBOUNCE 5
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#endif
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// Maximum debounce: 255ms
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#if DEBOUNCE > UINT8_MAX
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# undef DEBOUNCE
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# define DEBOUNCE UINT8_MAX
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#endif
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#define DEBOUNCE_ELAPSED 0
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#if DEBOUNCE > 0
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typedef uint8_t debounce_counter_t;
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// Uses MATRIX_ROWS_PER_HAND instead of MATRIX_ROWS to support split keyboards
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static debounce_counter_t debounce_counters[MATRIX_ROWS_PER_HAND] = {DEBOUNCE_ELAPSED};
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static bool counters_need_update;
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static bool cooked_changed;
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static inline void update_debounce_counters_and_transfer_if_expired(matrix_row_t raw[], matrix_row_t cooked[], uint8_t elapsed_time);
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static inline void start_debounce_counters(matrix_row_t raw[], matrix_row_t cooked[]);
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void debounce_init(void) {}
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bool debounce(matrix_row_t raw[], matrix_row_t cooked[], bool changed) {
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static fast_timer_t last_time;
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bool updated_last = false;
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cooked_changed = false;
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if (counters_need_update) {
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fast_timer_t now = timer_read_fast();
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fast_timer_t elapsed_time = TIMER_DIFF_FAST(now, last_time);
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last_time = now;
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updated_last = true;
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if (elapsed_time > 0) {
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// Update debounce counters with elapsed timer clamped to UINT8_MAX
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update_debounce_counters_and_transfer_if_expired(raw, cooked, MIN(elapsed_time, UINT8_MAX));
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}
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}
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if (changed) {
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if (!updated_last) {
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last_time = timer_read_fast();
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}
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start_debounce_counters(raw, cooked);
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}
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return cooked_changed;
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}
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/**
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* @brief Updates debounce counters and transfers debounced row states if the debounce period has expired.
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*
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* Iterates through each row in the matrix and checks its debounce counter. If the debounce period has expired
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* for a row, the debounced state is updated to match the raw state. Otherwise, the debounce counter is decremented
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* by the elapsed time and marked for further updates.
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*
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* @param raw The current raw key state matrix.
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* @param cooked The debounced key state matrix to be updated.
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* @param elapsed_time The time elapsed since the last debounce update, in milliseconds.
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*/
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static inline void update_debounce_counters_and_transfer_if_expired(matrix_row_t raw[], matrix_row_t cooked[], uint8_t elapsed_time) {
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counters_need_update = false;
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for (uint8_t row = 0; row < MATRIX_ROWS_PER_HAND; row++) {
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if (debounce_counters[row] != DEBOUNCE_ELAPSED) {
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if (debounce_counters[row] <= elapsed_time) {
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debounce_counters[row] = DEBOUNCE_ELAPSED;
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cooked_changed |= cooked[row] ^ raw[row];
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cooked[row] = raw[row];
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} else {
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debounce_counters[row] -= elapsed_time;
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counters_need_update = true;
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}
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}
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}
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}
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/**
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* @brief Initializes debounce counters for rows with changed states.
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*
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* For each row in the matrix, this function checks if the raw state differs from the debounced state.
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* If a change is detected and the debounce counter has elapsed, the counter is set to the debounce period
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* and marked for update. Otherwise, the counter is cleared.
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*
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* @param raw The current raw key state matrix.
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* @param cooked The debounced key state matrix.
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*/
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static inline void start_debounce_counters(matrix_row_t raw[], matrix_row_t cooked[]) {
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for (uint8_t row = 0; row < MATRIX_ROWS_PER_HAND; row++) {
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if (raw[row] != cooked[row]) {
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debounce_counters[row] = DEBOUNCE;
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counters_need_update = true;
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} else {
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debounce_counters[row] = DEBOUNCE_ELAPSED;
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}
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}
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}
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#else
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# include "none.c"
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#endif
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