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/* Copyright 2020 Dimitris Papavasiliou <dpapavas@protonmail.ch>
*
* 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 3 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 <https://www.gnu.org/licenses/>.
*/
#include <LUFA/Drivers/USB/USB.h>
#include "lagrange.h"
#ifndef SPLIT_USB_TIMEOUT_POLL
# define SPLIT_USB_TIMEOUT_POLL 10
#endif
/* Instead of timing out, the slave waits indefinitely for the other
* side to signal that it has become master. This avoids both sides
* assuming the slave role when the USB port is powered but not
* otherwise active (e.g. when the host is turned off, or suspended).
* The SPI SS line is used for signaling. On power-up it is
* configured as input with pull-up enabled. When one side assumes
* the master role, it reconfigures the line for SPI, and pulls it low
* to select the slave, which doubles as the signal. */
bool is_keyboard_master(void) {
static int8_t is_master = -1;
if (is_master < 0) {
while (readPin(SPI_SS_PIN)) {
if (USB_Device_IsAddressSet()) {
is_master = 1;
return is_master;
}
wait_ms(SPLIT_USB_TIMEOUT_POLL);
}
is_master = 0;
USB_Disable();
USB_DeviceState = DEVICE_STATE_Unattached;
}
return is_master;
}
void keyboard_pre_init_kb(void) {
setPinInputHigh(SPI_SS_PIN);
keyboard_pre_init_user();
}
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