summaryrefslogtreecommitdiffstats
path: root/keyboards/handwired/dqz11n1g/matrix.c
blob: f9f3f2b68fd1ebbdddc04f34a9e737894804d023 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
/*
  Copyright (c) 2022 David Kuehling <dvdkhlng TA posteo TOD de>

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 2 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#include <stdint.h>
#include <stdbool.h>
#include <string.h>

#include <avr/io.h>

#include "spi_master.h"
#include "quantum.h"
#include "matrix.h"

static pin_t row_pins[MATRIX_ROWS] = MATRIX_ROW_PINS;

static void unselect_rows(void);

void matrix_init_custom(void) {
    /* initialize row pins */
    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
        setPinOutput(row_pins[row]);
    }
    unselect_rows();

    /* columns read via shift-register on SPI lines */

    /* Enable SPI, Master, set clock rate fck/2.  First bit already at Qh
     * output before clock edge (CPHA=0).  SN74HC165 shift register shifts
     * on low-to-high transition (CPOL=1).  Receive the LSB first (DORD=1).
     */
    bool lsbFirst = true;
    uint8_t mode = 2;  /* CPOL=1, CPHA=0 */
    uint16_t divisor = 16;

    /* According to Atmega32U4 datasheet, PB0 *must* be set to output,
     * otherwise it will interfere with SPI master operation.  On pro-micro
     * it's connected to a yellew LED. */
    pin_t slavePin = PB0;
    spi_init();
    spi_start(slavePin, lsbFirst, mode, divisor);

    /* Initialize pin controlling the shift register's SH/~LD pin */
    setPinOutput(ROW_SHIFT_PIN);
}

static void select_row(uint8_t row) {
    pin_t pin = row_pins[row];
    if (pin != NO_PIN) {
        writePinHigh(pin);
    }
}

static void unselect_row(uint8_t row) {
    pin_t pin = row_pins[row];
    if (pin != NO_PIN) {
        writePinLow(pin);
    }
}

static void unselect_rows(void) {
    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
        unselect_row(row);
    }
}

bool matrix_read_cols_on_row(matrix_row_t current_matrix[], uint8_t current_row) {
    /* Start with a clear matrix row */
    matrix_row_t current_row_value = 0;

    /* Set shift register SH/~LD pin to "load" mode */
    writePinLow(ROW_SHIFT_PIN);
    select_row(current_row);
    matrix_output_select_delay();

    /* Set shift register SH/~LD pin to "shift" mode */
    writePinHigh(ROW_SHIFT_PIN);

    /* For each octet of columns... */
    for (uint8_t col_index = 0; col_index < MATRIX_COLS; col_index += 8) {
        spi_status_t read_result = spi_read();
        if (read_result >= 0) {
            /* only if SPI read successful: populate the matrix row with the
               state of the 8 consecutive column bits */
            current_row_value |= ((matrix_row_t)read_result << col_index);
        }
    }

    /* Unselect row & wait for all columns signals to go high. */
    unselect_row(current_row);
    matrix_output_unselect_delay(current_row, current_row_value != 0); 

    /* Update row in matrix. */
    if (current_row_value != current_matrix[current_row]) {
        current_matrix[current_row] = current_row_value;
        return true;
    }

    return false;
}

bool matrix_scan_custom(matrix_row_t curr_matrix[]) {
    bool changed = false;

    /* set row, read cols */
    for (uint8_t current_row = 0; current_row < MATRIX_ROWS; current_row++) {
        changed |= matrix_read_cols_on_row(curr_matrix, current_row);
    }

    return changed;
}

/*
 * Local Variables:
 * c-basic-offset:4
 * fill-column: 76
 * End:
 */