Index: firmware/App/Modes/ModePreTreat.c
===================================================================
diff -u -r8e2cfecc47bb3912078b29513f1717c1567f0071 -r5413ebeb2cb61163574550c7b2ca212ae3e307a3
--- firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 8e2cfecc47bb3912078b29513f1717c1567f0071)
+++ firmware/App/Modes/ModePreTreat.c	(.../ModePreTreat.c)	(revision 5413ebeb2cb61163574550c7b2ca212ae3e307a3)
@@ -35,16 +35,24 @@
 
 static BOOL treatStartReqReceived = FALSE;                              ///< Flag indicates user requests treatment begin.
 static BOOL patientConnectionStartReqReceived = FALSE;                  ///< Flag indicates user requests patient connection.
+static BOOL alarmActionStopReceived = FALSE;                            ///< Flag indicates alarm action stop received.
+static BOOL alarmActionResumeReceived = FALSE;                          ///< Flag indicates alarm action resume received.
 
 static HD_PRE_TREATMENT_MODE_STATE_T currentPreTreatmentState;          ///< Current state of pre-treatment mode state machine.
+static HD_PRE_TREATMENT_MODE_STATE_T resumePreTreatmentState;           ///< Pre-treatment mode state to be resumed when alarm action resume signal receives.
 
 // ********** private function prototypes **********
 
+static void handleAlarmActionStop( void );
+static void handleAlarmActionResume( void );
+
 static HD_PRE_TREATMENT_MODE_STATE_T handleSelfTestNoCartState( void );
 static HD_PRE_TREATMENT_MODE_STATE_T handleSelfTestDryState( void );
 static HD_PRE_TREATMENT_MODE_STATE_T handlePrimeState( void );
+static HD_PRE_TREATMENT_MODE_STATE_T handleRecirculateStartState( void );
 static HD_PRE_TREATMENT_MODE_STATE_T handleRecirculateState( void );
 static HD_PRE_TREATMENT_MODE_STATE_T handlePatientConnectionState( void );
+static HD_PRE_TREATMENT_MODE_STATE_T handlePretreatmentPauseState( void );
 
 /*********************************************************************//**
  * @brief
@@ -57,7 +65,10 @@
 {
     treatStartReqReceived = FALSE;
     patientConnectionStartReqReceived = FALSE;
+    alarmActionStopReceived = FALSE;
+    alarmActionResumeReceived = FALSE;
     currentPreTreatmentState = HD_PRE_TREATMENT_START_STATE;
+    resumePreTreatmentState = HD_PRE_TREATMENT_START_STATE;
 }
 
 /*********************************************************************//**
@@ -116,6 +127,10 @@
             currentPreTreatmentState = handlePrimeState();
             break;
 
+        case HD_PRE_TREATMENT_RECIRCULATE_START_STATE:
+            currentPreTreatmentState = handleRecirculateStartState();
+            break;
+
         case HD_PRE_TREATMENT_RECIRCULATE_STATE:
             currentPreTreatmentState = handleRecirculateState();
             break;
@@ -124,6 +139,10 @@
             currentPreTreatmentState = handlePatientConnectionState();
             break;
 
+        case HD_PRE_TREATMENT_PAUSE_STATE:
+            currentPreTreatmentState = handlePretreatmentPauseState();
+            break;
+
         default:
             currentPreTreatmentState = HD_PRE_TREATMENT_START_STATE;
             SET_ALARM_WITH_2_U32_DATA( ALARM_ID_HD_SOFTWARE_FAULT, SW_FAULT_ID_MODE_PRE_TREATMENT_INVALID_STATE, (U32)currentPreTreatmentState );
@@ -150,6 +169,7 @@
         treatStartReqReceived = TRUE;
         result = TRUE;
     }
+
     sendTreatmentStartResponseMsg( result, 0 ); // TODO - provide reason code if rejected
 
     return result;
@@ -166,32 +186,99 @@
  *************************************************************************/
 void signalAlarmActionToPreTreatmentMode( ALARM_ACTION_T action )
 {
-    if ( HD_PRE_TREATMENT_PRIME_STATE == currentPreTreatmentState )
+    switch( action )
     {
-        signalAlarmActionToPrimeMode( action );
+        case ALARM_ACTION_STOP:
+            handleAlarmActionStop();
+            break;
+
+        case ALARM_ACTION_RESUME:
+            handleAlarmActionResume();
+            break;
+
+        case ALARM_ACTION_END_TREATMENT:
+            requestNewOperationMode( MODE_POST );
+            break;
+
+        case ALARM_ACTION_ACK:
+            // Nothing to be done here
+            break;
+
+        default:
+            // Ignore
+            break;
     }
-    else
+}
+
+/*********************************************************************//**
+ * @brief
+ * The handleAlarmActionStop function forwards the alarm action to corresponding
+ * sub-mode and sets appropriate flag to allow corresponding sub-mode handles.
+ * @details Inputs: currentPreTreatmentState
+ * @details Outputs: signals corresponding sub-mode of alarm action
+ * @return none
+ *************************************************************************/
+static void handleAlarmActionStop( void )
+{
+    switch ( currentPreTreatmentState )
     {
-        switch( action )
-        {
-            case ALARM_ACTION_STOP:
-                break;
+        case HD_PRE_TREATMENT_PRIME_STATE:
+            signalAlarmActionToPrimeMode( ALARM_ACTION_STOP );
+            break;
 
-            case ALARM_ACTION_RESUME:
-                break;
+        case HD_PRE_TREATMENT_RECIRCULATE_STATE:
+            // The corresponding sub-mode will handle the signal
+            alarmActionStopReceived = TRUE;
+            break;
 
-            case ALARM_ACTION_END_TREATMENT:
-                requestNewOperationMode( MODE_POST );
-                break;
+        case HD_PRE_TREATMENT_START_STATE:
+        case HD_PRE_TREATMENT_WATER_SAMPLE_STATE:
+        case HD_PRE_TREATMENT_SELF_TEST_NO_CART_STATE:
+        case HD_PRE_TREATMENT_SELF_TEST_DRY_STATE:
+        case HD_PRE_TREATMENT_CART_INSTALL_STATE:
+        case HD_PRE_TREATMENT_PATIENT_CONNECTION_STATE:
+            // do nothing
+            break;
 
-            case ALARM_ACTION_ACK:
-                // Nothing to be done here
-                break;
+        default:
+            SET_ALARM_WITH_2_U32_DATA( ALARM_ID_HD_SOFTWARE_FAULT, SW_FAULT_ID_MODE_PRE_TREATMENT_INVALID_STATE, (U32)currentPreTreatmentState );
+            break;
+    }
+}
 
-            default:
-                // Ignore
-                break;
-        }
+/*********************************************************************//**
+ * @brief
+ * The handleAlarmActionResume function forwards the alarm action to corresponding
+ * sub-mode and sets appropriate flag to allow corresponding sub-mode handles.
+ * @details Inputs: currentPreTreatmentState
+ * @details Outputs: signals corresponding sub-mode of alarm action
+ * @return none
+ *************************************************************************/
+static void handleAlarmActionResume( void )
+{
+    switch ( currentPreTreatmentState )
+    {
+        case HD_PRE_TREATMENT_PRIME_STATE:
+            signalAlarmActionToPrimeMode( ALARM_ACTION_RESUME );
+            break;
+
+        case HD_PRE_TREATMENT_RECIRCULATE_STATE:
+        case HD_PRE_TREATMENT_SELF_TEST_NO_CART_STATE:
+        case HD_PRE_TREATMENT_SELF_TEST_DRY_STATE:
+        case HD_PRE_TREATMENT_START_STATE:
+        case HD_PRE_TREATMENT_WATER_SAMPLE_STATE:
+        case HD_PRE_TREATMENT_CART_INSTALL_STATE:
+        case HD_PRE_TREATMENT_PATIENT_CONNECTION_STATE:
+            // do nothing
+            break;
+
+        case HD_PRE_TREATMENT_PAUSE_STATE:
+            alarmActionResumeReceived = TRUE;
+            break;
+
+        default:
+            SET_ALARM_WITH_2_U32_DATA( ALARM_ID_HD_SOFTWARE_FAULT, SW_FAULT_ID_MODE_PRE_TREATMENT_INVALID_STATE, (U32)currentPreTreatmentState );
+            break;
     }
 }
 
@@ -257,27 +344,40 @@
 
     if ( TRUE == isWetSelfTestsPassed() )
     {
-        state = HD_PRE_TREATMENT_RECIRCULATE_STATE;
+        state = HD_PRE_TREATMENT_RECIRCULATE_START_STATE;
         activateAlarmNoData( ALARM_ID_PRIME_COMPLETED_LOW_PRIORITY );
-
-        setValvePosition( VDI, VALVE_POSITION_C_CLOSE );
-        setValvePosition( VDO, VALVE_POSITION_C_CLOSE );
-        setValvePosition( VBA, VALVE_POSITION_B_OPEN );
-        setValvePosition( VBV, VALVE_POSITION_B_OPEN );
-        setValveAirTrap( STATE_CLOSED );
-        cmdSetDGActiveReservoir( DG_RESERVOIR_1 );
-        cmdStartDGTrimmerHeater();
-
-        setBloodPumpTargetFlowRate( BLOOD_PUMP_RECIRC_FLOW_RATE, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
-        setDialInPumpTargetFlowRate( DIALYSATE_PUMP_RECIRC_FLOW_RATE, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
-        signalDialOutPumpHardStop();
     }
 
     return state;
 }
 
 /*********************************************************************//**
  * @brief
+ * The handleRecirculateStartState function change valves and heater settings
+ * for recirculation state during pre-treatment mode.
+ * @details Inputs: none
+ * @details Outputs: controlled valves and pumps
+ * @return current state (sub-mode)
+ *************************************************************************/
+static HD_PRE_TREATMENT_MODE_STATE_T handleRecirculateStartState( void )
+{
+    setValvePosition( VDI, VALVE_POSITION_C_CLOSE );
+    setValvePosition( VDO, VALVE_POSITION_C_CLOSE );
+    setValvePosition( VBA, VALVE_POSITION_B_OPEN );
+    setValvePosition( VBV, VALVE_POSITION_B_OPEN );
+    setValveAirTrap( STATE_CLOSED );
+    cmdSetDGActiveReservoir( DG_RESERVOIR_1 );
+    cmdStartDGTrimmerHeater();
+
+    setBloodPumpTargetFlowRate( BLOOD_PUMP_RECIRC_FLOW_RATE, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
+    setDialInPumpTargetFlowRate( DIALYSATE_PUMP_RECIRC_FLOW_RATE, MOTOR_DIR_FORWARD, PUMP_CONTROL_MODE_OPEN_LOOP );
+    signalDialOutPumpHardStop();
+
+    return HD_PRE_TREATMENT_RECIRCULATE_STATE;
+}
+
+/*********************************************************************//**
+ * @brief
  * The handleRecirculateState function handles blood and dialysate circuits
  * recirculation state during pre-treatment mode.
  * @details Inputs: none
@@ -296,6 +396,17 @@
         state = HD_PRE_TREATMENT_PATIENT_CONNECTION_STATE;
     }
 
+    if ( TRUE == alarmActionStopReceived )
+    {
+        signalDialOutPumpHardStop();
+        signalDialInPumpHardStop();
+        signalBloodPumpHardStop();
+        cmdStopDGTrimmerHeater();
+
+        state = HD_PRE_TREATMENT_PAUSE_STATE;
+        resumePreTreatmentState = HD_PRE_TREATMENT_RECIRCULATE_START_STATE;
+    }
+
     return state;
 }
 
@@ -317,4 +428,24 @@
     return HD_PRE_TREATMENT_PATIENT_CONNECTION_STATE;
 }
 
+/*********************************************************************//**
+ * @brief
+ * The handlePretreatmentPauseState function handles pre-treatment pause state.
+ * @details Inputs: previousPrimeState
+ * @details Outputs: primeStartTime, primeResumeReqReceived
+ * @return current state
+ *************************************************************************/
+static HD_PRE_TREATMENT_MODE_STATE_T handlePretreatmentPauseState( void )
+{
+    HD_PRE_TREATMENT_MODE_STATE_T state = HD_PRE_TREATMENT_PAUSE_STATE;
+
+    if ( TRUE == alarmActionResumeReceived )
+    {
+        alarmActionResumeReceived = FALSE;
+        state = resumePreTreatmentState;
+    }
+
+    return state;
+}
+
 /**@}*/