matrix.c (3588B)
1 /* 2 * Copyright 2020 Richard Titmuss (richard.titmuss@gmail.com) 3 * Copyright 2012-2018 Jun Wako, Jack Humbert, Yiancar 4 * 5 * This program is free software: you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation, either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program. If not, see <http://www.gnu.org/licenses/>. 17 */ 18 19 #include "matrix.h" 20 #include "mcp23018.h" 21 22 #define SPLIT_MATRIX_COLS (MATRIX_COLS / 2) 23 #define SECONDARY_ROW_OFFSET (MATRIX_ROWS / 2) 24 25 typedef uint16_t mcp23018_pin_t; 26 27 static const pin_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS; 28 static const pin_t col_pins[SPLIT_MATRIX_COLS] = MATRIX_COL_PINS; 29 static const mcp23018_pin_t secondary_row_pins[MATRIX_ROWS] = SECONDARY_ROW_PINS; 30 static const mcp23018_pin_t secondary_col_pins[SPLIT_MATRIX_COLS] = SECONDARY_COL_PINS; 31 32 static void select_row(uint8_t row) { 33 gpio_set_pin_output(row_pins[row]); 34 gpio_write_pin_low(row_pins[row]); 35 } 36 37 static void unselect_row(uint8_t row) { gpio_set_pin_input_high(row_pins[row]); } 38 39 static void unselect_rows(void) { 40 for (uint8_t x = 0; x < MATRIX_ROWS; x++) { 41 gpio_set_pin_input_high(row_pins[x]); 42 } 43 } 44 45 static void select_secondary_row(uint8_t row) { 46 uint8_t gpioa = 0xFF & ~secondary_row_pins[row]; 47 mcp23018_writeReg(GPIOA, &gpioa, 1); 48 } 49 50 static void init_pins(void) { 51 unselect_rows(); 52 for (uint8_t x = 0; x < SPLIT_MATRIX_COLS; x++) { 53 gpio_set_pin_input_high(col_pins[x]); 54 } 55 } 56 57 static matrix_row_t read_cols(void) { 58 matrix_row_t state = 0; 59 60 // For each col... 61 for (uint8_t col_index = 0; col_index < SPLIT_MATRIX_COLS; col_index++) { 62 // Select the col pin to read (active low) 63 uint8_t pin_state = gpio_read_pin(col_pins[col_index]); 64 65 // Populate the matrix row with the state of the col pin 66 state |= pin_state ? 0 : (MATRIX_ROW_SHIFTER << col_index); 67 } 68 69 return state; 70 } 71 72 static matrix_row_t read_secondary_cols(void) { 73 matrix_row_t state = 0; 74 75 uint8_t mcp23018_pin_state[2]; 76 if (mcp23018_readReg(GPIOA, mcp23018_pin_state, 2)) { 77 return 0; 78 } 79 80 uint16_t pins = mcp23018_pin_state[0] | (mcp23018_pin_state[1] << 8); 81 82 for (uint8_t col_index = 0; col_index < SPLIT_MATRIX_COLS; col_index++) { 83 uint16_t pin_state = pins & (secondary_col_pins[col_index]); 84 state |= pin_state ? 0 : (MATRIX_ROW_SHIFTER << col_index); 85 } 86 87 return state; 88 } 89 90 static bool read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) { 91 matrix_row_t last_row_value = current_matrix[current_row]; 92 93 select_row(current_row); 94 select_secondary_row(current_row); 95 96 current_matrix[current_row] = read_cols() | (read_secondary_cols() << 6); 97 98 unselect_row(current_row); 99 100 return (last_row_value != current_matrix[current_row]); 101 } 102 103 void matrix_init_custom(void) { init_pins(); } 104 105 bool matrix_scan_custom(matrix_row_t current_matrix[]) { 106 bool changed = false; 107 108 for (uint8_t current_row = 0; current_row < MATRIX_ROWS; current_row++) { 109 changed |= read_cols_on_row(current_matrix, current_row); 110 } 111 112 return changed; 113 }