matrix.c

   1 /*
   2  * scan matrix
   3  */
   4 #include <avr/io.h>
   5 #include <util/delay.h>
   6 #include "keymap.h"
   7 #include "matrix.h"
   8 #include "print.h"
   9
  10 uint8_t *matrix;
  11 uint8_t *prev_matrix;
  12 static uint8_t _matrix0[MATRIX_ROWS];
  13 static uint8_t _matrix1[MATRIX_ROWS];
  14
  15 static uint8_t read_col(void);
  16 static void select_row(uint8_t row);
  17
  18
  19 void matrix_init(void)
  20 {
  21     // Column: input w/pullup
  22     DDRB = 0x00;
  23     PORTB = 0xFF;
  24
  25     // Row: Hi-Z(unselected)
  26     // PD:0,1,2,3,6,7
  27     // PC:6,7
  28     // PF:7
  29     DDRD = 0x00;
  30     PORTD = 0x00;
  31     DDRC = 0x00;
  32     PORTC = 0x00;
  33     DDRF = 0x00;
  34     PORTF = 0x00;
  35
  36     for (int i=0; i < MATRIX_ROWS; i++) {
  37         _matrix0[i] = 0xFF;
  38         _matrix1[i] = 0xFF;
  39     }
  40     matrix = _matrix0;
  41     prev_matrix = _matrix1;
  42 }
  43
  44 uint8_t matrix_scan(void)
  45 {
  46     uint8_t row, state;
  47     uint8_t *tmp;
  48
  49     tmp = prev_matrix;
  50     prev_matrix = matrix;
  51     matrix = tmp;
  52
  53     for (row = 0; row < MATRIX_ROWS; row++) {
  54         select_row(row);
  55         _delay_us(30);  // without this wait read unstable value.
  56         state = read_col();
  57
  58         matrix[row] = state;
  59     }
  60     return 1;
  61 }
  62
  63 static uint8_t read_col(void)
  64 {
  65     return PINB;
  66 }
  67
  68 static void select_row(uint8_t row)
  69 {
  70     switch (row) {
  71         case 0:
  72             DDRD  = (1<<0);
  73             PORTD = 0x00;
  74             DDRC  = 0x00;
  75             PORTC = 0x00;
  76             DDRF  = 0x00;
  77             PORTF = 0x00;
  78             break;
  79         case 1:
  80             DDRD  = (1<<1);
  81             PORTD = 0x00;
  82             DDRC  = 0x00;
  83             PORTC = 0x00;
  84             DDRF  = 0x00;
  85             PORTF = 0x00;
  86             break;
  87         case 2:
  88             DDRD  = (1<<2);
  89             PORTD = 0x00;
  90             DDRC  = 0x00;
  91             PORTC = 0x00;
  92             DDRF  = 0x00;
  93             PORTF = 0x00;
  94             break;
  95         case 3:
  96             DDRD  = (1<<3);
  97             PORTD = 0x00;
  98             DDRC  = 0x00;
  99             PORTC = 0x00;
 100             DDRF  = 0x00;
 101             PORTF = 0x00;
 102             break;
 103         case 4:
 104             DDRD  = (1<<6);
 105             PORTD = 0x00;
 106             DDRC  = 0x00;
 107             PORTC = 0x00;
 108             DDRF  = 0x00;
 109             PORTF = 0x00;
 110             break;
 111         case 5:
 112             DDRD  = (1<<7);
 113             PORTD = 0x00;
 114             DDRC  = 0x00;
 115             PORTC = 0x00;
 116             DDRF  = 0x00;
 117             PORTF = 0x00;
 118             break;
 119         case 6:
 120             DDRD  = 0x00;
 121             PORTD = 0x00;
 122             DDRC  = (1<<6);
 123             PORTC = 0x00;
 124             DDRF  = 0x00;
 125             PORTF = 0x00;
 126             break;
 127         case 7:
 128             DDRD  = 0x00;
 129             PORTD = 0x00;
 130             DDRC  = (1<<7);
 131             PORTC = 0x00;
 132             DDRF  = 0x00;
 133             PORTF = 0x00;
 134             break;
 135         case 8:
 136             DDRD  = 0x00;
 137             PORTD = 0x00;
 138             DDRC  = 0x00;
 139             PORTC = 0x00;
 140             DDRF  = (1<<7);
 141             PORTF = 0x00;
 142             break;
 143     }
 144 }