keyboard/hbkb/matrix.c

   1 /*
   2 Copyright 2012 Jun Wako <wakojun@gmail.com>
   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 <stdint.h>
  19 #include <stdbool.h>
  20 #include <avr/io.h>
  21 #include <util/delay.h>
  22 #include "print.h"
  23 #include "debug.h"
  24 #include "util.h"
  25 #include "matrix.h"
  26
  27
  28 /*
  29  * Happy Buckling Keyboard(IBM Model M mod)
  30  *
  31  * Pin usage:
  32  *   COL: PD0-7
  33  *   ROW: PB0-7, PF4-7
  34  */
  35 #ifndef DEBOUNCE
  36 #   define DEBOUNCE     10
  37 #endif
  38 static uint8_t debouncing = DEBOUNCE;
  39
  40 /* matrix state(1:on, 0:off) */
  41 static matrix_row_t matrix[MATRIX_ROWS];
  42 static matrix_row_t matrix_debouncing[MATRIX_ROWS];
  43
  44 static matrix_row_t read_cols(void);
  45 static void unselect_rows(void);
  46 static void select_row(uint8_t row);
  47
  48
  49 void matrix_init(void)
  50 {
  51     // JTAG disable for PORT F. write JTD bit twice within four cycles.
  52     MCUCR |= (1<<JTD);
  53     MCUCR |= (1<<JTD);
  54
  55     // initialize rows
  56     unselect_rows();
  57
  58     // initialize columns to input with pull-up(DDR:0, PORT:1)
  59     DDRD = 0x00;
  60     PORTD = 0xFF;
  61
  62     // initialize matrix state: all keys off
  63     for (uint8_t i=0; i < MATRIX_ROWS; i++) {
  64         matrix[i] = 0;
  65         matrix_debouncing[i] = 0;
  66     }
  67 }
  68
  69 uint8_t matrix_scan(void)
  70 {
  71     for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
  72         select_row(i);
  73         _delay_us(30);  // without this wait read unstable value.
  74         matrix_row_t cols = read_cols();
  75         if (matrix_debouncing[i] != cols) {
  76             matrix_debouncing[i] = cols;
  77             if (debouncing) {
  78                 debug("bounce!: "); debug_hex(debouncing); debug("\n");
  79             }
  80             debouncing = DEBOUNCE;
  81         }
  82         unselect_rows();
  83     }
  84
  85     if (debouncing) {
  86         if (--debouncing) {
  87             _delay_ms(1);
  88         } else {
  89             for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
  90                 matrix[i] = matrix_debouncing[i];
  91             }
  92         }
  93     }
  94
  95     return 1;
  96 }
  97
  98 inline
  99 matrix_row_t matrix_get_row(uint8_t row)
 100 {
 101     return matrix[row];
 102 }
 103
 104 inline
 105 static matrix_row_t read_cols(void)
 106 {
 107     return ~PIND;
 108 }
 109
 110 inline
 111 static void unselect_rows(void)
 112 {
 113     // Hi-Z(DDR:0, PORT:0) to unselect
 114     DDRB  &= ~0b11111111;
 115     PORTB &= ~0b11111111;
 116     DDRF  &= ~0b11110000;
 117     PORTF &= ~0b11110000;
 118 }
 119
 120 inline
 121 static void select_row(uint8_t row)
 122 {
 123     // Output low(DDR:1, PORT:0) to select
 124     switch (row) {
 125         case 0:
 126         case 1:
 127         case 2:
 128         case 3:
 129         case 4:
 130         case 5:
 131         case 6:
 132         case 7:
 133             DDRB  |=  (1<<row);
 134             PORTB &= ~(1<<row);
 135             break;
 136         case 8:
 137             DDRF  |=  (1<<4);
 138             PORTF &= ~(1<<4);
 139             break;
 140         case 9:
 141         case 10:
 142         case 11:
 143             DDRF  |=  (1<<(row-4));
 144             PORTF &= ~(1<<(row-4));
 145             break;
 146     }
 147 }