diff --git a/rawhid.h b/rawhid.h
index 6dcaca1..48cdcb0 100644
--- a/rawhid.h
+++ b/rawhid.h
@@ -21,8 +21,20 @@ void hid_send_state(void);
 
 
 // Sent by host when connection is initiated.
+//
+// Packet structure:
+// Data:		| cmd |
+// # of Bytes:	|  1  |
 #define CMD_HELLO 0x00
 
+// Sent periodically by host to test connection.
+// Keyboard should ignore this command.
+//
+// Packet structure:
+// Data:		| cmd |
+// # of Bytes:	|  1  |
+#define CMD_RUTHERE 0x01
+
 // Send keyboard state to host.
 //
 // Packet structure:
@@ -33,7 +45,7 @@ void hid_send_state(void);
 // 0x00: RGBMatrix disabled
 // 0x01: normal animation, no HID data.
 // 0x02: FFT Animation
-#define CMD_SEND_STATE 0x01
+#define CMD_SEND_STATE 0x02
 
 
 // Animation data. Sent by host.
@@ -47,9 +59,10 @@ void hid_send_state(void);
 //
 // data:
 // Animation data. Content depends on data type.
-#define CMD_ANIM_DATA 0x02
+#define CMD_ANIM_DATA 0x03
 
 // Data for FFT animation.
 // Data segment consists of 10 bits, each representing the height of a column.
 // Minimum height is 0, maximum is 250.
 #define CMD_ANIM_DATA_fft 0x00
+