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/*
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:
*/
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