matrix.c (3471B)
1 /* 2 Copyright 2012-2018 Jun Wako, Jack Humbert, Yiancar 3 4 This program is free software: you can redistribute it and/or modify 5 it under the terms of the GNU General Public License as published by 6 the Free Software Foundation, either version 2 of the License, or 7 (at your option) any later version. 8 9 This program is distributed in the hope that it will be useful, 10 but WITHOUT ANY WARRANTY; without even the implied warranty of 11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 GNU General Public License for more details. 13 14 You should have received a copy of the GNU General Public License 15 along with this program. If not, see <http://www.gnu.org/licenses/>. 16 */ 17 18 #include "matrix.h" 19 #include "sn74x138.h" 20 21 static const pin_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS; 22 static const pin_t col_pins[MATRIX_COLS] = MATRIX_COL_PINS; 23 24 /* Columns 6-12 use a 74HC138 3-to-8 demultiplexer. 25 * 26 * 0: C7 27 * 1: B6 28 * 2: C6 29 * 3: B4 30 * 4: B5 31 * 5: D7 32 * 33 * A2 A1 A0 34 * D0 D1 D2 35 * 6: 1 1 1 36 * 7: 1 1 0 37 * 8: 1 0 1 38 * 9: 1 0 0 39 * 10: 0 1 1 40 * 11: 0 1 0 41 * 12: 0 0 1 42 * 43 * 13: D3 44 * 14: B7 45 * 15: B3 46 */ 47 static void select_col(uint8_t col) { 48 if (col_pins[col] != NO_PIN) { 49 gpio_write_pin_low(col_pins[col]); 50 } else { 51 sn74x138_set_addr(13 - col); 52 } 53 } 54 55 static void unselect_col(uint8_t col) { 56 if (col_pins[col] != NO_PIN) { 57 gpio_set_pin_output(col_pins[col]); 58 gpio_write_pin_high(col_pins[col]); 59 } else { 60 sn74x138_set_addr(0); 61 } 62 } 63 64 static void unselect_cols(void) { 65 // Native 66 for (uint8_t x = 0; x < MATRIX_COLS; x++) { 67 if (col_pins[x] != NO_PIN) { 68 gpio_set_pin_output(col_pins[x]); 69 gpio_write_pin_high(col_pins[x]); 70 } 71 } 72 73 // Demultiplexer 74 sn74x138_set_addr(0); 75 } 76 77 static void init_pins(void) { 78 unselect_cols(); 79 for (uint8_t x = 0; x < MATRIX_ROWS; x++) { 80 gpio_set_pin_input_high(row_pins[x]); 81 } 82 } 83 84 static bool read_rows_on_col(matrix_row_t current_matrix[], uint8_t current_col) { 85 bool matrix_changed = false; 86 87 // Select col and wait for col selection to stabilize 88 select_col(current_col); 89 matrix_io_delay(); 90 91 // For each row... 92 for (uint8_t row_index = 0; row_index < MATRIX_ROWS; row_index++) { 93 // Store last value of row prior to reading 94 matrix_row_t last_row_value = current_matrix[row_index]; 95 96 // Check row pin state 97 if (gpio_read_pin(row_pins[row_index]) == 0) { 98 // Pin LO, set col bit 99 current_matrix[row_index] |= (MATRIX_ROW_SHIFTER << current_col); 100 } else { 101 // Pin HI, clear col bit 102 current_matrix[row_index] &= ~(MATRIX_ROW_SHIFTER << current_col); 103 } 104 105 // Determine if the matrix changed state 106 if ((last_row_value != current_matrix[row_index]) && !(matrix_changed)) { 107 matrix_changed = true; 108 } 109 } 110 111 // Unselect col 112 unselect_col(current_col); 113 114 return matrix_changed; 115 } 116 117 void matrix_init_custom(void) { 118 // initialize demultiplexer 119 sn74x138_init(); 120 // initialize key pins 121 init_pins(); 122 } 123 124 bool matrix_scan_custom(matrix_row_t current_matrix[]) { 125 bool changed = false; 126 127 // Set col, read rows 128 for (uint8_t current_col = 0; current_col < MATRIX_COLS; current_col++) { 129 changed |= read_rows_on_col(current_matrix, current_col); 130 } 131 132 return changed; 133 }