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/* Copyright 2023 ebastler and elpekenin
*
* 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 "pca9555.h"
# include "quantum.h"
// PCA9555 i2c address, 0x20: A0 = 0, A1 = 0, A2 = 0
# define IC1 0x20
// Define how long to wait to reach the IO expander after connection loss again
// Since this board is modular, it should not spam unnecessary i2c requests if used without a module
# define RETRY_TIMESPAN 2000
typedef enum {
PLUGGED ,
DOUBTFUL ,
UNPLUGGED
} expander_status_t ;
void pca9555_setup ( void ) {
// Initialize the expander, no need to set ports to inputs as that is the default behavior
pca9555_init ( IC1 ) ;
}
void matrix_init_custom ( void ) {
// Encoder pushbutton on the MCU is connected to PD2
setPinInputHigh ( D2 ) ;
pca9555_setup ( ) ;
}
bool matrix_scan_custom ( matrix_row_t current_matrix [ ] ) {
static expander_status_t status = DOUBTFUL ;
static uint32_t retry_timer = 0 ;
// initialize one byte filled with 1
uint8_t pin_states = 0xFF ;
if ( status ! = UNPLUGGED | | timer_elapsed32 ( retry_timer ) > RETRY_TIMESPAN ) {
// If the chip was unplugged before, it needs to be re-initialized
if ( status = = UNPLUGGED ) {
pca9555_setup ( ) ;
}
// Read the entire port into this byte, 1 = not pressed, 0 = pressed
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bool ret = pca9555_read_pins ( IC1 , PCA9555_PORT0 , & pin_states ) ;
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// Update state
if ( ret ) {
status = PLUGGED ;
} else {
switch ( status ) {
case PLUGGED :
status = DOUBTFUL ;
break ;
case DOUBTFUL :
status = UNPLUGGED ;
break ;
// If we've diagnosed as unplugged, update timer to not read I2C
case UNPLUGGED :
retry_timer = timer_read32 ( ) ;
}
}
}
// Shift pin states by 1 to make room for the switch connected to the MCU, then OR them together and invert (as QMK uses inverted logic compared to the electrical levels)
matrix_row_t data = ~ ( pin_states < < 1 | readPin ( D2 ) ) ;
bool changed = current_matrix [ 0 ] ! = data ;
current_matrix [ 0 ] = data ;
return changed ;
}