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- /* Copyright 2021 Jay Greco
- *
- * 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/>.
- */
-
- /*
- Remote keyboard is an experimental feature that allows for connecting another
- keyboard, macropad, numpad, or accessory without requiring an additional USB connection.
- The "remote keyboard" forwards its keystrokes using UART serial over TRRS. Dynamic VUSB
- detect allows the keyboard automatically switch to host or remote mode depending on
- which is connected to the USB port.
-
- Possible functionality includes the ability to send data from the host to the remote using
- a reverse link, allowing for LED sync, configuration, and more data sharing between devices.
- This will require a new communication protocol, as the current one is limited.
- */
-
- #include "remote_kb.h"
- #include "uart.h"
-
- uint8_t
- msg[UART_MSG_LEN],
- msg_idx = 0;
-
- bool
- is_host = true;
-
- // Private functions
-
- static bool vbus_detect(void) {
- #if defined(__AVR_ATmega32U4__)
- //returns true if VBUS is present, false otherwise.
- USBCON |= (1 << OTGPADE); //enables VBUS pad
- _delay_us(10);
- return (USBSTA & (1<<VBUS)); //checks state of VBUS
- #else
- #error vbus_detect is not implemented for this architecure!
- #endif
- }
-
- static uint8_t chksum8(const unsigned char *buf, size_t len) {
- unsigned int sum;
- for (sum = 0 ; len != 0 ; len--)
- sum += *(buf++);
- return (uint8_t)sum;
- }
-
- static void send_msg(uint16_t keycode, bool pressed) {
- msg[IDX_PREAMBLE] = UART_PREAMBLE;
- msg[IDX_KCLSB] = (keycode & 0xFF);
- msg[IDX_KCMSB] = (keycode >> 8) & 0xFF;
- msg[IDX_PRESSED] = pressed;
- msg[IDX_CHECKSUM] = chksum8(msg, UART_MSG_LEN-1);
-
- for (int i=0; i<UART_MSG_LEN; i++) {
- uart_putchar(msg[i]);
- }
- }
-
- static void print_message_buffer(void) {
- for (int i=0; i<UART_MSG_LEN; i++) {
- dprintf("msg[%u]: %u\n", i, msg[i]);
- }
- }
-
- static void process_uart(void) {
- uint8_t chksum = chksum8(msg, UART_MSG_LEN-1);
- if (msg[IDX_PREAMBLE] != UART_PREAMBLE || msg[IDX_CHECKSUM] != chksum) {
- dprintf("UART checksum mismatch!\n");
- print_message_buffer();
- dprintf("calc checksum: %u\n", chksum);
- } else {
- uint16_t keycode = (uint16_t)msg[IDX_KCLSB] | ((uint16_t)msg[IDX_KCMSB] << 8);
- bool pressed = (bool)msg[IDX_PRESSED];
- if (IS_RM_KC(keycode)) {
- keyrecord_t record;
- record.event.pressed = pressed;
- if (pressed) dprintf("Remote macro: press [%u]\n", keycode);
- else dprintf("Remote macro: release [%u]\n", keycode);
- process_record_user(keycode, &record);
- } else {
- if (pressed) {
- dprintf("Remote: press [%u]\n", keycode);
- register_code(keycode);
- } else {
- dprintf("Remote: release [%u]\n", keycode);
- unregister_code(keycode);
- }
- }
- }
- }
-
- static void get_msg(void) {
- while (uart_available()) {
- msg[msg_idx] = uart_getchar();
- dprintf("idx: %u, recv: %u\n", msg_idx, msg[msg_idx]);
- if (msg_idx == 0 && (msg[msg_idx] != UART_PREAMBLE)) {
- dprintf("Byte sync error!\n");
- msg_idx = 0;
- } else if (msg_idx == (UART_MSG_LEN-1)) {
- process_uart();
- msg_idx = 0;
- } else {
- msg_idx++;
- }
- }
- }
-
- static void handle_host_incoming(void) {
- get_msg();
- }
-
- static void handle_host_outgoing(void) {
- // for future reverse link use
- }
-
- static void handle_remote_incoming(void) {
- // for future reverse link use
- }
-
- static void handle_remote_outgoing(uint16_t keycode, keyrecord_t *record) {
- if (IS_HID_KC(keycode) || IS_RM_KC(keycode)) {
- dprintf("Remote: send [%u]\n", keycode);
- send_msg(keycode, record->event.pressed);
- }
- }
-
- // Public functions
-
- void matrix_init_remote_kb(void) {
- uart_init(SERIAL_UART_BAUD);
- is_host = vbus_detect();
- }
-
- void process_record_remote_kb(uint16_t keycode, keyrecord_t *record) {
- #if defined (KEYBOARD_HOST)
- handle_host_outgoing();
-
- #elif defined(KEYBOARD_REMOTE)
- handle_remote_outgoing(keycode, record);
-
- #else //auto check with VBUS
- if (is_host) {
- handle_host_outgoing();
- }
- else {
- handle_remote_outgoing(keycode, record);
- }
- #endif
- }
-
- void matrix_scan_remote_kb(void) {
- #if defined(KEYBOARD_HOST)
- handle_host_incoming();
-
- #elif defined (KEYBOARD_REMOTE)
- handle_remote_incoming();
-
- #else //auto check with VBUS
- if (is_host) {
- handle_host_incoming();
- }
- else {
- handle_remote_incoming();
- }
- #endif
- }
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