134 lines
3.4 KiB
C
134 lines
3.4 KiB
C
/*
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Copyright 2012-2018 Jun Wako, Jack Humbert, Yiancar
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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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#include "matrix.h"
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#include "sn74x138.h"
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static const pin_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS;
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static const pin_t col_pins[MATRIX_COLS] = MATRIX_COL_PINS;
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/* Columns 6-12 use a 74HC138 3-to-8 demultiplexer.
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*
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* 0: C7
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* 1: B6
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* 2: C6
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* 3: B4
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* 4: B5
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* 5: D7
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*
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* A2 A1 A0
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* D0 D1 D2
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* 6: 1 1 1
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* 7: 1 1 0
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* 8: 1 0 1
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* 9: 1 0 0
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* 10: 0 1 1
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* 11: 0 1 0
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* 12: 0 0 1
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*
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* 13: D3
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* 14: B7
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* 15: B3
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*/
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static void select_col(uint8_t col) {
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if (col_pins[col] != NO_PIN) {
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gpio_write_pin_low(col_pins[col]);
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} else {
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sn74x138_set_addr(13 - col);
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}
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}
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static void unselect_col(uint8_t col) {
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if (col_pins[col] != NO_PIN) {
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gpio_set_pin_output(col_pins[col]);
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gpio_write_pin_high(col_pins[col]);
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} else {
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sn74x138_set_addr(0);
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}
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}
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static void unselect_cols(void) {
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// Native
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for (uint8_t x = 0; x < MATRIX_COLS; x++) {
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if (col_pins[x] != NO_PIN) {
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gpio_set_pin_output(col_pins[x]);
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gpio_write_pin_high(col_pins[x]);
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}
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}
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// Demultiplexer
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sn74x138_set_addr(0);
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}
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static void init_pins(void) {
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unselect_cols();
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for (uint8_t x = 0; x < MATRIX_ROWS; x++) {
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gpio_set_pin_input_high(row_pins[x]);
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}
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}
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static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col) {
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bool matrix_changed = false;
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// Select col and wait for col selection to stabilize
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select_col(current_col);
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matrix_io_delay();
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// For each row...
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for (uint8_t row_index = 0; row_index < MATRIX_ROWS; row_index++) {
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// Store last value of row prior to reading
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matrix_row_t last_row_value = current_matrix[row_index];
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// Check row pin state
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if (gpio_read_pin(row_pins[row_index]) == 0) {
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// Pin LO, set col bit
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current_matrix[row_index] |= (MATRIX_ROW_SHIFTER << current_col);
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} else {
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// Pin HI, clear col bit
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current_matrix[row_index] &= ~(MATRIX_ROW_SHIFTER << current_col);
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}
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// Determine if the matrix changed state
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if ((last_row_value != current_matrix[row_index]) && !(matrix_changed)) {
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matrix_changed = true;
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}
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}
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// Unselect col
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unselect_col(current_col);
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return matrix_changed;
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}
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void matrix_init_custom(void) {
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// initialize demultiplexer
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sn74x138_init();
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// initialize key pins
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init_pins();
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}
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bool matrix_scan_custom(matrix_row_t current_matrix[]) {
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bool changed = false;
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// Set col, read rows
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for (uint8_t current_col = 0; current_col < MATRIX_COLS; current_col++) {
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changed |= read_rows_on_col(current_matrix, current_col);
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}
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return changed;
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}
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