Index: firmware/App/Services/SystemComm.h
===================================================================
diff -u -ra7bf3ca23ea37a61000379facae628a31b3ecc59 -r62a4d7b976107f7ac4d5013ce06f38f4a0bf65bd
--- firmware/App/Services/SystemComm.h	(.../SystemComm.h)	(revision a7bf3ca23ea37a61000379facae628a31b3ecc59)
+++ firmware/App/Services/SystemComm.h	(.../SystemComm.h)	(revision 62a4d7b976107f7ac4d5013ce06f38f4a0bf65bd)
@@ -7,8 +7,8 @@
 *
 * @file SystemComm.h
 *
-* @author (last) Sean
-* @date (last) 27-Feb-2020
+* @author (last) Quang Nguyen
+* @date (last) 24-Aug-2020
 *
 * @author (original) Dara Navaei
 * @date (original) 05-Nov-2019
@@ -22,23 +22,31 @@
 #include "CommBuffers.h"
 #include "MsgQueues.h"
 
+/**
+ *  @defgroup SystemComm SystemComm
+ *  @brief System communication module. Manages incoming and outgoing CAN frames.
+ *
+ *  @addtogroup SystemComm
+ *  @{
+ */
+
 // ********** public definitions **********
 
-#define MESSAGE_SYNC_BYTE           0xA5
+#define MESSAGE_SYNC_BYTE           0xA5                                                                ///< Denali message syncronization byte.
 
-#define CAN_MESSAGE_PAYLOAD_SIZE    8
+#define CAN_MESSAGE_PAYLOAD_SIZE    8                                                                   ///< CAN frame payload size (in bytes).
 #ifdef DEBUG_ENABLED
     #define PC_MESSAGE_PACKET_SIZE  8
 #endif
 
-#define MSG_ID_ACK                  0xFFFF
-#define MSG_ACK_BIT                 0x8000
-#define MAX_MSG_SEQ_NO              0x7FFF
-#define MIN_MSG_SEQ_NO              0x0001
-#define MAX_ACK_MSG_SIZE            ( sizeof( MESSAGE_WRAPPER_T ) + 1 + CAN_MESSAGE_PAYLOAD_SIZE )  // must hold full (wrapped) message + sync + any CAN padding
+#define MSG_ID_ACK                  0xFFFF                                                              ///< Denali message ID for acknowledging received messages (when required).
+#define MSG_ACK_BIT                 0x8000                                                              ///< ACK bit in sequence number that indicates an ACK is required.
+#define MAX_MSG_SEQ_NO              0x7FFF                                                              ///< Maximum sequence number for Denali message (then wraps to 1).
+#define MIN_MSG_SEQ_NO              0x0001                                                              ///< Minimum sequence number for Denali message.
+#define MAX_ACK_MSG_SIZE            ( sizeof( MESSAGE_WRAPPER_T ) + 1 + CAN_MESSAGE_PAYLOAD_SIZE )      ///< Maximum size (in bytes) of Denali message including full (wrapped) message + sync + any CAN padding)
+
+typedef COMM_BUFFER_T   CAN_MESSAGE_BOX_T;                                                              ///< the CAN comm buffers align with the active CAN message boxes
 
-typedef COMM_BUFFER_T   CAN_MESSAGE_BOX_T;       // the first 12 comm buffers align with the 12 active CAN message boxes
-
 // ********** public function prototypes **********
 
 void initSystemComm( void );
@@ -49,7 +57,11 @@
     void handleUARTMsgRecvPacketInterrupt( void );
     void handleUARTMsgXmitPacketInterrupt( void );
 #endif
-BOOL isHDCommunicating( void );
-BOOL addMsgToPendingACKList( MESSAGE_T *msg, COMM_BUFFER_T channel, U08 *msgData, U32 len );
-
-#endif
+
+BOOL isCANBoxForXmit( CAN_MESSAGE_BOX_T srcCANBox );
+BOOL isCANBoxForRecv( CAN_MESSAGE_BOX_T srcCANBox );
+BOOL isHDCommunicating( void );
+BOOL isDGOnlyCANNode( void );
+BOOL addMsgToPendingACKList( MESSAGE_T *msg, COMM_BUFFER_T channel, U08 *msgData, U32 len );
+
+#endif