Index: firmware/App/Services/SystemComm.c
===================================================================
diff -u -r8ea2ea3096334f18a1bd38018bc4359e16374d83 -r66cc826068b54bc436cde0fae70a05ba6c1ac974
--- firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 8ea2ea3096334f18a1bd38018bc4359e16374d83)
+++ firmware/App/Services/SystemComm.c	(.../SystemComm.c)	(revision 66cc826068b54bc436cde0fae70a05ba6c1ac974)
@@ -8,7 +8,7 @@
 * @file    SystemComm.c
 *
 * @author  (last)      Dara Navaei
-* @date    (last)      22-Feb-2022
+* @date    (last)      31-Mar-2022
 *
 * @author  (original)  Dara Navaei
 * @date    (original)  05-Nov-2019
@@ -100,7 +100,7 @@
 
 static volatile BOOL dgIsOnlyCANNode = TRUE;                                ///< flag indicating whether DG is alone on CAN bus.
 static U32 canXmitRetryCtr = 0;                                             ///< counter for CAN transmit retries.
-static volatile BOOL hdIsCommunicating = FALSE;                             ///< has HD sent a message since last check
+static OVERRIDE_U32_T hdCommunicationStatus = {0, 0, 0, 0};                 ///< has HD sent a message since last check
 static volatile U32 timeOfLastHDCheckIn = 0;                                ///< last time we received an HD broadcast
 
 // ********** private function prototypes **********
@@ -153,7 +153,7 @@
  *************************************************************************/
 BOOL isHDCommunicating( void )
 {
-    return hdIsCommunicating;
+    return getU32OverrideValue(&hdCommunicationStatus);
 }
 
 /*********************************************************************//**
@@ -496,7 +496,7 @@
                     // if message from HD broadcast channel, update HD comm status
                     if ( COMM_BUFFER_IN_CAN_HD_BROADCAST == MSG_IN_BUFFERS[ i ] )
                     {
-                        hdIsCommunicating = TRUE;
+                        hdCommunicationStatus.data = (U32)TRUE;
                         timeOfLastHDCheckIn = getMSTimerCount();
                     }
                 }
@@ -654,7 +654,7 @@
 {
     if ( TRUE == didTimeout( timeOfLastHDCheckIn, HD_COMM_TIMEOUT_IN_MS ) )
     {
-        hdIsCommunicating = FALSE;
+        hdCommunicationStatus.data = FALSE;
         //activateAlarmNoData( ALARM_ID_HD_COMM_TIMEOUT );
     }
 }
@@ -1153,6 +1153,14 @@
                 handleTestFansRPMAlarmStartTimeOffsetRequest( message );
                 break;
 
+            case MSG_ID_DG_USED_ACID_VOLUME_ML_OVERRIDE:
+                handleTestUsedAcidVolumeMLOverrideRequest( message );
+                break;
+
+            case MSG_ID_DG_USED_BICARB_VOLUME_ML_OVERRIDE:
+                handleTestUsedBicarbVolumeMLOverrideRequest( message );
+                break;
+
             case MSG_ID_DG_GET_SW_CONFIG_RECORD:
                 handleGetDGSoftwareConfigRecord( message );
                 break;
@@ -1165,11 +1173,64 @@
                 handleSetFansDutyCycleOverrideRequest( message );
                 break;
 
+            case MSG_ID_DG_HD_COMMUNICATION_STATUS_OVERRIDE:
+                handleTestHDCommunicationStatusOverrideRequest( message );
+                break;
+
             default:
                 // TODO - unrecognized message ID received - ignore
                 break;
         }
     }
 }
 
+
+/*************************************************************************
+ *                       TEST SUPPORT FUNCTIONS
+ *************************************************************************/
+
+/*********************************************************************//**
+ * @brief
+ * The testSetHDCommunicationStatus function sets the override
+ * of the HD communication status.
+ * @details Inputs: none
+ * @details Outputs: hdCommunicationStatus
+ * @return TRUE if reset successful, FALSE if not
+ *************************************************************************/
+BOOL testSetHDCommunicationStatus( U32 value )
+{
+    BOOL result = FALSE;
+
+    if (TRUE == isTestingActivated() )
+    {
+        result = TRUE;
+        hdCommunicationStatus.ovData = value;
+        hdCommunicationStatus.override = OVERRIDE_KEY;
+
+    }
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The testResetHDCommuncationStatus function resets the override
+ * of the HD communication status.
+ * @details Inputs: none
+ * @details Outputs: hdCommunicationStatus
+ * @return TRUE if reset successful, FALSE if not
+ *************************************************************************/
+BOOL testResetHDCommuncationStatus( void )
+{
+    BOOL result = FALSE;
+
+    if (TRUE == isTestingActivated() )
+    {
+        result = TRUE;
+        hdCommunicationStatus.override = OVERRIDE_RESET;
+        hdCommunicationStatus.ovData = hdCommunicationStatus.ovInitData;
+
+    }
+    return result;
+}
+
 /**@}*/