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/* Copyright 2022
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "matrix.h"
#include "gpio.h"
#include "sn74x154.h"
static const pin_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS;
/* All columns use a 74HC154 4-to-16 demultiplexer.
* D3 is the enable pin, must be set high to use it.
*
* A3 A2 A1 A0
* D7 D6 D5 D4
* 0: 0 0 0 0
* 1: 0 0 0 1
* 2: 0 0 1 0
* 3: 0 0 1 1
* 4: 0 1 0 0
* 5: 0 1 0 1
* 6: 0 1 1 0
* 7: 0 1 1 1
* 8: 1 0 0 0
* 9: 1 0 0 1
* 10: 1 0 1 0
* 11: 1 0 1 1
* 12: 1 1 0 0
* 13: 1 1 0 1
* 14: 1 1 1 0
* 15: 1 1 1 1
*/
static void select_col(uint8_t col) {
sn74x154_set_addr(col);
}
static void init_pins(void) {
for (uint8_t x = 0; x < MATRIX_ROWS; x++) {
setPinInputHigh(row_pins[x]);
}
}
static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col) {
bool matrix_changed = false;
// Select col and wait for col seleciton to stabilize
select_col(current_col);
matrix_io_delay();
// For each row...
for (uint8_t row_index = 0; row_index < MATRIX_ROWS; row_index++) {
// Store last value of row prior to reading
matrix_row_t last_row_value = current_matrix[row_index];
// Check row pin state
if (readPin(row_pins[row_index]) == 0) {
// Pin LO, set col bit
current_matrix[row_index] |= (MATRIX_ROW_SHIFTER << current_col);
} else {
// Pin HI, clear col bit
current_matrix[row_index] &= ~(MATRIX_ROW_SHIFTER << current_col);
}
// Determine if the matrix changed state
if ((last_row_value != current_matrix[row_index]) && !(matrix_changed)) {
matrix_changed = true;
}
}
return matrix_changed;
}
void matrix_init_custom(void) {
// initialize demultiplexer
sn74x154_init();
sn74x154_set_enabled(true);
// initialize key pins
init_pins();
}
bool matrix_scan_custom(matrix_row_t current_matrix[]) {
bool changed = false;
// Set col, read rows
for (uint8_t current_col = 0; current_col < MATRIX_COLS; current_col++) {
changed |= read_rows_on_col(current_matrix, current_col);
}
return changed;
}
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