+ break;
+ case 1: // NKRO Mode
+ // Only send press and release events
+ if ( stateType == 0x00 && state == 0x02 ) // Hold state
+ return;
+
+ // Determine if setting or unsetting the bitfield (press == set)
+ if ( stateType == 0x00 && state == 0x01 ) // Press state
+ keyPress = 1;
+ break;
+ }
+
+ // Get the keycode from arguments
+ uint8_t key = args[0];
+
+ // Depending on which mode the keyboard is in, USBKeys_Keys array is used differently
+ // Boot mode - Maximum of 6 byte codes
+ // NKRO mode - Each bit of the 26 byte corresponds to a key
+ // Bits 0 - 45 (bytes 0 - 5) correspond to USB Codes 4 - 49 (Main)
+ // Bits 48 - 161 (bytes 6 - 20) correspond to USB Codes 51 - 164 (Secondary)
+ // Bits 168 - 213 (bytes 21 - 26) correspond to USB Codes 176 - 221 (Tertiary)
+ // Bits 214 - 216 unused
+ uint8_t bytePosition = 0;
+ uint8_t byteShift = 0;
+ switch ( USBKeys_Protocol )
+ {
+ case 0: // Boot Mode
+ // Set the modifier bit if this key is a modifier
+ if ( (key & 0xE0) == 0xE0 ) // AND with 0xE0 (Left Ctrl, first modifier)
+ {
+ USBKeys_Modifiers |= 1 << (key ^ 0xE0); // Left shift 1 by key XOR 0xE0
+ }
+ // Normal USB Code
+ else
+ {
+ // USB Key limit reached
+ if ( USBKeys_Sent >= USB_BOOT_MAX_KEYS )
+ {
+ warn_print("USB Key limit reached");
+ return;
+ }
+
+ // Make sure key is within the USB HID range
+ if ( key <= 104 )
+ {
+ USBKeys_Keys[USBKeys_Sent++] = key;
+ }
+ // Invalid key
+ else
+ {
+ warn_msg("USB Code above 104/0x68 in Boot Mode: ");
+ printHex( key );
+ print( NL );
+ }
+ }
+ break;
+
+ case 1: // NKRO Mode
+ // Set the modifier bit if this key is a modifier
+ if ( (key & 0xE0) == 0xE0 ) // AND with 0xE0 (Left Ctrl, first modifier)
+ {
+ if ( keyPress )
+ {
+ USBKeys_Modifiers |= 1 << (key ^ 0xE0); // Left shift 1 by key XOR 0xE0
+ }
+ else // Release
+ {
+ USBKeys_Modifiers &= ~(1 << (key ^ 0xE0)); // Left shift 1 by key XOR 0xE0
+ }
+
+ USBKeys_Changed |= USBKeyChangeState_Modifiers;
+ break;
+ }
+ // First 6 bytes
+ else if ( key >= 4 && key <= 49 )
+ {
+ // Lookup (otherwise division or multiple checks are needed to do alignment)
+ // Starting at 0th position, each byte has 8 bits, starting at 4th bit
+ uint8_t keyPos = key + (0 * 8 - 4); // Starting position in array, Ignoring 4 keys
+ switch ( keyPos )
+ {
+ byteLookup( 0 );
+ byteLookup( 1 );
+ byteLookup( 2 );
+ byteLookup( 3 );
+ byteLookup( 4 );
+ byteLookup( 5 );
+ }
+
+ USBKeys_Changed |= USBKeyChangeState_MainKeys;
+ }
+ // Next 14 bytes
+ else if ( key >= 51 && key <= 155 )
+ {
+ // Lookup (otherwise division or multiple checks are needed to do alignment)
+ // Starting at 6th byte position, each byte has 8 bits, starting at 51st bit
+ uint8_t keyPos = key + (6 * 8 - 51); // Starting position in array
+ switch ( keyPos )
+ {
+ byteLookup( 6 );
+ byteLookup( 7 );
+ byteLookup( 8 );
+ byteLookup( 9 );
+ byteLookup( 10 );
+ byteLookup( 11 );
+ byteLookup( 12 );
+ byteLookup( 13 );
+ byteLookup( 14 );
+ byteLookup( 15 );
+ byteLookup( 16 );
+ byteLookup( 17 );
+ byteLookup( 18 );
+ byteLookup( 19 );
+ }
+
+ USBKeys_Changed |= USBKeyChangeState_SecondaryKeys;
+ }
+ // Next byte
+ else if ( key >= 157 && key <= 164 )
+ {
+ // Lookup (otherwise division or multiple checks are needed to do alignment)
+ uint8_t keyPos = key + (20 * 8 - 157); // Starting position in array, Ignoring 6 keys
+ switch ( keyPos )
+ {
+ byteLookup( 20 );
+ }
+
+ USBKeys_Changed |= USBKeyChangeState_TertiaryKeys;
+ }
+ // Last 6 bytes
+ else if ( key >= 176 && key <= 221 )
+ {
+ // Lookup (otherwise division or multiple checks are needed to do alignment)
+ uint8_t keyPos = key + (21 * 8 - 176); // Starting position in array
+ switch ( keyPos )
+ {
+ byteLookup( 21 );
+ byteLookup( 22 );
+ byteLookup( 23 );
+ byteLookup( 24 );
+ byteLookup( 25 );
+ byteLookup( 26 );
+ }
+
+ USBKeys_Changed |= USBKeyChangeState_QuartiaryKeys;
+ }
+ // Received 0x00
+ // This is a special USB Code that internally indicates a "break"
+ // It is used to send "nothing" in order to break up sequences of USB Codes
+ else if ( key == 0x00 )
+ {
+ USBKeys_Changed |= USBKeyChangeState_MainKeys;
+
+ // Also flush out buffers just in case
+ Output_flushBuffers();
+ break;
+ }
+ // Invalid key
+ else
+ {
+ warn_msg("USB Code not within 4-49 (0x4-0x31), 51-155 (0x33-0x9B), 157-164 (0x9D-0xA4), 176-221 (0xB0-0xDD) or 224-231 (0xE0-0xE7) NKRO Mode: ");
+ printHex( key );
+ print( NL );
+ break;