RemdesKVM/usbkvm/usbkvm_fw2/keyboard_emu.ino

/*
  ketboard_emu.ino

  This file handle keyboard emulation and key writes
*/
#define MAX_KEYBOARD_HID_KEYCODE_NO 6
#define ENABLE_KEYBOARD_DEBUG_PRINTOUT

/* Modifier keycode for CH9329 */
#define MOD_LCTRL 0x01
#define MOD_LSHIFT 0x02
#define MOD_LALT 0x04
#define MOD_LGUI 0x08
#define MOD_RCTRL 0x10
#define MOD_RSHIFT 0x20
#define MOD_RALT 0x40
#define MOD_RGUI 0x80

/* Runtime variables */
uint8_t keyboard_state[6] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };

//byte 0: Computer connected
//byte 1:
//      bit 0: NUM LOCK
//      bit 1: CAPS LOCK
//      bit 2: SCROLL LOCK
uint8_t keyboard_leds[2] = { 0x00, 0x00 };
extern uint8_t kbCmdBuf[MAX_CMD_LEN];
extern uint8_t kbCmdIndex;
extern uint8_t kbCmdCounter;

/* Function Prototypes */
void send_cmd(uint8_t cmd, uint8_t* data, uint8_t length);

/* Request CH9329 response with current keyboard status */
void keyboard_get_info() {
  send_cmd(0x01, NULL, 0x00);
}

/* Callback handler for setting keyboard status */
void handle_keyboard_get_info_reply() {
  keyboard_leds[0] = kbCmdBuf[6];
  keyboard_leds[1] = kbCmdBuf[7];

#ifdef ENABLE_KEYBOARD_DEBUG_PRINTOUT
  for (int i = 0; i < kbCmdIndex; i++) {
    uint8_t b = kbCmdBuf[i];
    USBSerial_print("0x");
    if (b < 0x10) USBSerial_print("0");
    USBSerial_print(b, HEX);
    USBSerial_print(" ");
  }

  USBSerial_println(keyboard_leds[0] ? "Connected" : "Not Connected");
  USBSerial_println((keyboard_leds[1] & 0x01) ? "NUMLOCK ON" : "NUMLOCK OFF");
  USBSerial_println((keyboard_leds[1] & 0x02) ? "CAPSLOCK ON" : "CAPSLOCK OFF");
  USBSerial_println((keyboard_leds[1] & 0x04) ? "SCROLLLOCK ON" : "SCROLLLOCK OFF");
#endif
}

/* helper to write an array of uint8_t to CH9329 */
void Serial0_writeBuf(const uint8_t* data, uint8_t len) {
  for (uint8_t i = 0; i < len; i++) {
    Serial0_write(data[i]);
  }
}

/* Send key combinations, keycode must be an array with length 6 */
int keyboard_send_key_combinations(uint8_t modifiers, uint8_t* keycode, uint8_t length) {
  if (length != MAX_KEYBOARD_HID_KEYCODE_NO) {
    //This function must take in an array of 6 keycodes
    return -1;
  }
  uint8_t packet[14] = {
    0x57, 0xAB, 0x00, 0x02, 0x08,
    modifiers, 0x00,
    keycode[0], keycode[1], keycode[2], keycode[3], keycode[4], keycode[5],
    0x00
  };
  packet[13] = calcChecksum(packet, 13);
  Serial0_writeBuf(packet, 14);
  return 0;
}

/* Release all keypress on the current emulated keyboard */
void keyboard_release_all_keys() {
  uint8_t packet[] = {
    0x57, 0xAB, 0x00, 0x02, 0x08,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
    0x00  // checksum placeholder
  };
  packet[13] = calcChecksum(packet, 13);
  Serial0_writeBuf(packet, 14);
}

/* Convert JavaScrpt Keycode into HID keycode */
uint8_t javascript_keycode_to_hid_opcode(uint8_t keycode) {
  // Letters A-Z
  if (keycode >= 65 && keycode <= 90) {
    return (keycode - 65) + 0x04;  // 'A' is 0x04
  }

  // Numbers 1-9 (top row, not numpad)
  if (keycode >= 49 && keycode <= 57) {
    return (keycode - 48) + 0x1E;  // '1' is 0x1E
  }

  //Numpad 1-9
  if (keycode >= 97 && keycode <= 105) {
    return (keycode - 97) + 0x59;  // '1' (numpad) is 0x59
  }

  //F1 to F12
  if (keycode >= 112 && keycode <= 123) {
    return (keycode - 112) + 0x3A;  // 'F1' is 0x3A
  }

  switch (keycode) {
    case 8:
      return 0x2A;  // Backspace
    case 9:
      return 0x2B;  // Tab
    case 13:
      return 0x28;  // Enter
    case 16:
      return 0xE1;  //Left shift
    case 17:
      return 0xE0;  //Left Ctrl
    case 18:
      return 0xE6;  //Left Alt
    case 20:
      return 0x39;  // Caps Lock
    case 27:
      return 0x29;  // Escape
    case 32:
      return 0x2C;  // Spacebar
    case 33:
      return 0x4B;  // Page Up
    case 34:
      return 0x4E;  // Page Down
    case 35:
      return 0x4D;  // End
    case 36:
      return 0x4A;  // Home
    case 37:
      return 0x50;  // Left Arrow
    case 38:
      return 0x52;  // Up Arrow
    case 39:
      return 0x4F;  // Right Arrow
    case 40:
      return 0x51;  // Down Arrow
    case 44:
      return 0x46;  //Print Screen or F13 (Firefox)
    case 45:
      return 0x49;  // Insert
    case 46:
      return 0x4C;  // Delete
    case 48:
      return 0x27;  // 0 (not Numpads)

    // 49 - 57 Number row 1 - 9 handled above
    // 58 not supported
    case 59:
      return 0x33;  // ';'

    // 60 not supported
    case 61:
      return 0x2E;  // '='

    //62 - 90 not supported
    case 91:
      return 0xE3;  // Left GUI (Windows)
    case 92:
      return 0xE7;  // Right GUI
    case 93:
      return 0x65;  // Menu key
    // 64 - 65 not supported
    case 96:
      return 0x62;  //0 (Numpads)
    //Numpad 1 to 9 handled above
    case 106:
      return 0x55;  //* (Numpads)
    case 107:
      return 0x57;  //+ (Numpads)
    case 109:
      return 0x56;  //- (Numpads)
    case 110:
      return 0x63;  // dot (Numpads)
    case 111:
      return 0x54;  // divide (Numpads)

    // 112 - 123 F1 to F12 handled above
    // 124 - 143 F13 to F32 not supported
    case 144:
      return 0x53;  // Num Lock
    case 145:
      return 0x47;  // Scroll Lock

    // 146 - 185 not supported or not exists
    case 186:
      return 0x33;  // ;
    case 187:
      return 0x2E;  // =
    case 188:
      return 0x36;  // ,
    case 189:
      return 0x2D;  // -
    case 190:
      return 0x37;  // .
    case 191:
      return 0x38;  // /
    case 192:
      return 0x35;  // `
    case 219:
      return 0x2F;  // [
    case 220:
      return 0x31;  // backslash
    case 221:
      return 0x30;  // ]
    case 222:
      return 0x34;  // '

    default:
      return 0x00;  // Unknown / unsupported
  }
}