hhkb/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 // matrix is active low. (key on: 0/key off: 1)
  11 //
  12 // HHKB has no ghost and no bounce.
  13 // row: HC4051 select input channel(0-8)
  14 //      PB0, PB1, PB2(A, B, C)
  15 // col: LS145 select low output line(0-8)
  16 //      PB3, PB4, PB5, PB6(A, B, C, D)
  17 //      use D as ENABLE: (enable: 0/unenable: 1)
  18 // key: KEY: (on: 0/ off:1)
  19 //      UNKNOWN: unknown whether input or output
  20 //      PE6,PE7(KEY, UNKNOWN)
  21 #define COL_ENABLE              (1<<6)
  22 #define KEY_SELELCT(ROW, COL)   (PORTB = COL_ENABLE|(((COL)&0x07)<<3)|((ROW)&0x07))
  23 #define KEY_ENABLE              (PORTB &= ~COL_ENABLE)
  24 #define KEY_UNABLE              (PORTB |=  COL_ENABLE)
  25 #define KEY_ON                  ((PINE&(1<<6)) ? false : true)
  26
  27 // matrix state buffer
  28 uint8_t *matrix;
  29 uint8_t *matrix_prev;
  30 static uint8_t _matrix0[MATRIX_ROWS];
  31 static uint8_t _matrix1[MATRIX_ROWS];
  32
  33
  34 // this must be called once before matrix_scan.
  35 void matrix_init(void)
  36 {
  37     // row & col output(PB0-6)
  38     DDRB = 0xFF;
  39     PORTB = KEY_SELELCT(0, 0);
  40     // KEY & VALID input with pullup(PE6,7)
  41     DDRE = 0x3F;
  42     PORTE = 0xC0;
  43
  44     // initialize matrix state: all keys off
  45     for (int i=0; i < MATRIX_ROWS; i++) _matrix0[i] = 0xFF;
  46     for (int i=0; i < MATRIX_ROWS; i++) _matrix1[i] = 0xFF;
  47     matrix = _matrix0;
  48     matrix_prev = _matrix1;
  49 }
  50
  51 uint8_t matrix_scan(void)
  52 {
  53     uint8_t *tmp;
  54
  55     tmp = matrix_prev;
  56     matrix_prev = matrix;
  57     matrix = tmp;
  58
  59     for (int row = 0; row < MATRIX_ROWS; row++) {
  60         for (int col = 0; col < MATRIX_COLS; col++) {
  61             KEY_SELELCT(row, col);
  62             _delay_us(50);  // from logic analyzer chart
  63             KEY_ENABLE;
  64             _delay_us(10);  // from logic analyzer chart
  65             if (KEY_ON) {
  66                 matrix[row] &= ~(1<<col);
  67             } else {
  68                 matrix[row] |= (1<<col);
  69             }
  70             KEY_UNABLE;
  71             _delay_us(150);  // from logic analyzer chart
  72         }
  73     }
  74     return 1;
  75 }
  76
  77 bool matrix_is_modified(void) {
  78     for (int i=0; i <MATRIX_ROWS; i++) {
  79         if (matrix[i] != matrix_prev[i])
  80             return true;
  81     }
  82     return false;
  83 }
  84
  85 bool matrix_has_ghost(void) {
  86     return false;
  87 }
  88
  89 bool matrix_has_ghost_in_row(uint8_t row) {
  90     return false;
  91 }