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- /*
- * scan matrix
- */
- #include <avr/io.h>
- #include <util/delay.h>
- #include "keymap.h"
- #include "matrix.h"
-
- // matrix is active low. (key on: 0/key off: 1)
- // row: Hi-Z(unselected)/low output(selected)
- // PD:0,1,2,3,6,7/PC:6,7/PF:7
- // col: input w/pullup
- // PB:0-8
-
- // matrix state buffer
- uint8_t *matrix;
- uint8_t *matrix_prev;
- static uint8_t _matrix0[MATRIX_ROWS];
- static uint8_t _matrix1[MATRIX_ROWS];
-
- static uint8_t read_col(void);
- static void unselect_rows(void);
- static void select_row(uint8_t row);
-
-
- // this must be called once before matrix_scan.
- void matrix_init(void)
- {
- // initialize row and col
- unselect_rows();
- DDRB = 0x00;
- PORTB = 0xFF;
-
- // initialize matrix state: all keys off
- for (int i=0; i < MATRIX_ROWS; i++) _matrix0[i] = 0xFF;
- for (int i=0; i < MATRIX_ROWS; i++) _matrix1[i] = 0xFF;
- matrix = _matrix0;
- matrix_prev = _matrix1;
- }
-
- uint8_t matrix_scan(void)
- {
- uint8_t row, state;
- uint8_t *tmp;
-
- tmp = matrix_prev;
- matrix_prev = matrix;
- matrix = tmp;
-
- for (row = 0; row < MATRIX_ROWS; row++) {
- select_row(row);
- _delay_us(30); // without this wait read unstable value.
- state = read_col();
- unselect_rows();
-
- matrix[row] = state;
- }
- return 1;
- }
-
- bool matrix_is_modified(void) {
- for (int i=0; i <MATRIX_ROWS; i++) {
- if (matrix[i] != matrix_prev[i])
- return true;
- }
- return false;
- }
-
- bool matrix_has_ghost(void) {
- for (int i=0; i <MATRIX_ROWS; i++) {
- if (matrix_has_ghost_in_row(i))
- return true;
- }
- return false;
- }
-
- bool matrix_has_ghost_in_row(uint8_t row) {
- uint8_t state = ~matrix[row];
- // no ghost exists in case less than 2 keys on
- if (((state - 1) & state) == 0)
- return false;
-
- // ghost exists in case same state as other row
- for (int i=0; i < MATRIX_ROWS; i++) {
- if (i == row) continue;
- if ((~matrix[i] & state) == state) return true;
- }
- return false;
- }
-
- static uint8_t read_col(void)
- {
- return PINB;
- }
-
- static void unselect_rows(void) {
- DDRD = 0x00;
- PORTD = 0x00;
- DDRC = 0x00;
- PORTC = 0x00;
- DDRF = 0x00;
- PORTF = 0x00;
- }
-
- static void select_row(uint8_t row)
- {
- switch (row) {
- case 0:
- DDRD = (1<<0);
- PORTD = 0x00;
- DDRC = 0x00;
- PORTC = 0x00;
- DDRF = 0x00;
- PORTF = 0x00;
- break;
- case 1:
- DDRD = (1<<1);
- PORTD = 0x00;
- DDRC = 0x00;
- PORTC = 0x00;
- DDRF = 0x00;
- PORTF = 0x00;
- break;
- case 2:
- DDRD = (1<<2);
- PORTD = 0x00;
- DDRC = 0x00;
- PORTC = 0x00;
- DDRF = 0x00;
- PORTF = 0x00;
- break;
- case 3:
- DDRD = (1<<3);
- PORTD = 0x00;
- DDRC = 0x00;
- PORTC = 0x00;
- DDRF = 0x00;
- PORTF = 0x00;
- break;
- case 4:
- DDRD = (1<<6);
- PORTD = 0x00;
- DDRC = 0x00;
- PORTC = 0x00;
- DDRF = 0x00;
- PORTF = 0x00;
- break;
- case 5:
- DDRD = (1<<7);
- PORTD = 0x00;
- DDRC = 0x00;
- PORTC = 0x00;
- DDRF = 0x00;
- PORTF = 0x00;
- break;
- case 6:
- DDRD = 0x00;
- PORTD = 0x00;
- DDRC = (1<<6);
- PORTC = 0x00;
- DDRF = 0x00;
- PORTF = 0x00;
- break;
- case 7:
- DDRD = 0x00;
- PORTD = 0x00;
- DDRC = (1<<7);
- PORTC = 0x00;
- DDRF = 0x00;
- PORTF = 0x00;
- break;
- case 8:
- DDRD = 0x00;
- PORTD = 0x00;
- DDRC = 0x00;
- PORTC = 0x00;
- DDRF = (1<<7);
- PORTF = 0x00;
- break;
- }
- }
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