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77 lines
2.2 KiB
77 lines
2.2 KiB
/*
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Copyright 2021 Chad Austin <chad@chadaustin.me>
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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Symmetric per-row debounce algorithm. Changes only apply when
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DEBOUNCE milliseconds have elapsed since the last change.
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*/
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#include "debounce.h"
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#include "timer.h"
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#include <stdlib.h>
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#ifndef DEBOUNCE
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# define DEBOUNCE 5
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#endif
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static uint16_t last_time;
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// [row] milliseconds until key's state is considered debounced.
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static uint8_t* countdowns;
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// [row]
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static matrix_row_t* last_raw;
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void debounce_init(uint8_t num_rows) {
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countdowns = (uint8_t*)calloc(num_rows, sizeof(uint8_t));
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last_raw = (matrix_row_t*)calloc(num_rows, sizeof(matrix_row_t));
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last_time = timer_read();
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}
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void debounce_free(void) {
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free(countdowns);
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countdowns = NULL;
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free(last_raw);
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last_raw = NULL;
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}
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bool debounce(matrix_row_t raw[], matrix_row_t cooked[], uint8_t num_rows, bool changed) {
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uint16_t now = timer_read();
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uint16_t elapsed16 = TIMER_DIFF_16(now, last_time);
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last_time = now;
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uint8_t elapsed = (elapsed16 > 255) ? 255 : elapsed16;
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bool cooked_changed = false;
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uint8_t* countdown = countdowns;
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for (uint8_t row = 0; row < num_rows; ++row, ++countdown) {
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matrix_row_t raw_row = raw[row];
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if (raw_row != last_raw[row]) {
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*countdown = DEBOUNCE;
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last_raw[row] = raw_row;
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} else if (*countdown > elapsed) {
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*countdown -= elapsed;
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} else if (*countdown) {
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cooked_changed |= cooked[row] ^ raw_row;
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cooked[row] = raw_row;
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*countdown = 0;
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}
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}
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return cooked_changed;
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}
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bool debounce_active(void) {
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return true;
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}
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