Index: firmware/App/Services/TDInterface.c
===================================================================
diff -u -r57dd20557f066bf5d790ce25dd11c97bb93e3cde -rc07917caced76b53a0ed8f35167fac6f9d8310a4
--- firmware/App/Services/TDInterface.c	(.../TDInterface.c)	(revision 57dd20557f066bf5d790ce25dd11c97bb93e3cde)
+++ firmware/App/Services/TDInterface.c	(.../TDInterface.c)	(revision c07917caced76b53a0ed8f35167fac6f9d8310a4)
@@ -1,24 +1,27 @@
 /**************************************************************************
 *
-* Copyright (c) 2024-2024 Diality Inc. - All Rights Reserved.
+* Copyright (c) 2024-2025 Diality Inc. - All Rights Reserved.
 *
 * THIS CODE MAY NOT BE COPIED OR REPRODUCED IN ANY FORM, IN PART OR IN
 * WHOLE, WITHOUT THE EXPLICIT PERMISSION OF THE COPYRIGHT OWNER.
 *
 * @file    TDInterface.c
 *
-* @author  (last)      Vinayakam Mani
-* @date    (last)      28-Oct-2024
+* @author  (last)      Michael Garthwaite
+* @date    (last)      30-Oct-2025
 *
 * @author  (original)  Vinayakam Mani
-* @date    (original)  28-Oct-2024
+* @date    (original)  06-Nov-2024
 *
 ***************************************************************************/
 
+#include "DialysatePumps.h"
+#include "FPInterface.h"
 #include "Messaging.h"
 #include "MessagePayloads.h"
 #include "ModeGenDialysate.h"
 #include "ModeInitPOST.h"
+#include "ModePreGenDialysate.h"
 #include "ModeStandby.h"
 #include "OperationModes.h"
 #include "PersistentAlarm.h"
@@ -42,7 +45,7 @@
 static TD_OP_MODE_T tdCurrentOpMode;                                        ///< Current TD operation mode.
 static U32 tdSubMode;                                                       ///< Current state (sub-mode) of current TD operation mode.
 static F32 tdDialysateFlowrate;                                             ///< TD dialysate flow rate
-static F32 tdUFRate;                                                        ///< TD ultrafilteration rate
+static F32 tdUFRate;                                                        ///< TD ultrafiltration rate
 static F32 tdTargetDialysateTemp;                                           ///< TD target dialysate temperature
 static BOOL tdDialyzerBypass;                                               ///< TD dialyzer bypass
 static DD_ACID_TYPES_T tdAcidType;                                          ///< TD Acid type.
@@ -66,7 +69,7 @@
    // Initialize unit variables
     tdCurrentOpMode         = MODE_INIT;
     tdSubMode               = 0;
-    tdDialysateFlowrate     = MAX_DIALYSIS_FLOW_RATE;   // Will update later based on the TD value
+    tdDialysateFlowrate     = MAX_DIALYSATE_FLOW_RATE;   // Will update later based on the TD value
     tdUFRate                = 0.0F;
     tdTargetDialysateTemp   = 0.0F;
     tdDialyzerBypass        = FALSE;
@@ -190,7 +193,7 @@
  * The setTDUFRate function sets the latest TD UF rate.
  * @details \b Inputs: none
  * @details \b Outputs: tdUFRate
- * @param ultrafilteration flow rate.
+ * @param ultrafiltration flow rate.
  * @return none.
  *************************************************************************/
 void setTDUFRate( F32 ufRate )
@@ -221,7 +224,7 @@
  * @param Dialyzer Bypass enable.
  * @return none.
  *************************************************************************/
-void setTDDialyzerBypass( F32 dialBypass )
+void setTDDialyzerBypass( BOOL dialBypass )
 {
     tdDialyzerBypass = dialBypass;
 }
@@ -257,7 +260,7 @@
 
 /*********************************************************************//**
  * @brief
- * The getTDUFrate function gets the latest TD ultrafilteration flow
+ * The getTDUFrate function gets the latest TD ultrafiltration flow
  * rate.
  * @details \b Inputs: tdUFRate
  * @details \b Outputs: none
@@ -322,6 +325,56 @@
 
 /*********************************************************************//**
  * @brief
+ * The handlePreGenDialysateRequestMsg function handles a pre gen dailysate
+ * delivery request from TD to perform required self test and priming process.
+ * @details Inputs: none
+ * @details Outputs: message handled
+ * @param message a pointer to the message to handle
+ * @return TRUE if message is sucessfully parsed, FALSE if not.
+ *************************************************************************/
+BOOL handlePreGenDialysateRequestMsg( MESSAGE_T *message )
+{
+    BOOL result = FALSE;
+    REQUEST_REJECT_REASON_CODE_T fpReason = REQUEST_REJECT_REASON_NONE;
+
+    if ( message->hdr.payloadLen == sizeof( PRE_GEN_DIALYSATE_REQ_PAYLOAD_T ) )
+    {
+        PRE_GEN_DIALYSATE_REQ_PAYLOAD_T startPreGenRequest;
+        DD_OP_MODE_T ddMode = getCurrentOperationMode();
+
+        memcpy( &startPreGenRequest, message->payload, sizeof( PRE_GEN_DIALYSATE_REQ_PAYLOAD_T ) );
+
+        // Process the pre-gen dialysate delivery request message
+        if ( ( DD_MODE_STAN == ddMode ) && ( TRUE == startPreGenRequest.start ) )
+        {
+            // Start FP Pre-Generate Permeate
+            fpReason = signalStartGenPermeate();
+            // start pre-gen dialysate
+            result = requestDDPreGenStart();
+            // Update Temperature, Acid/Bicarb type and dialysate rate for pregen process.
+            setTDDialysateFlowrate( startPreGenRequest.dialRate );
+            setTDTargetDialysateTemperature( startPreGenRequest.dialTemp );
+            setTDAcidAndBicarbType( startPreGenRequest.acidType, startPreGenRequest.bicarbType );
+        }
+        else if ( DD_MODE_PREG == ddMode )
+        {
+            if ( FALSE == startPreGenRequest.start )
+            {
+                // stop pre generate diaysate delivery
+                result = requestDDPreGenStop();
+                // stop FP Pre-Generate Permeate
+                fpReason = signalStopGenPermeate();
+            }
+        }
+    }
+
+    sendAckResponseMsg( (MSG_ID_T)message->hdr.msgID, COMM_BUFFER_OUT_CAN_DD_2_TD, result );
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
  * The handleDialysateDeliveryRequestMsg function handles a dailysate
  * delivery request from TD and updates dialysate flowrate, UF rate,
  * dialysate temperature, dialyzer bypass and concentrate types ( acid
@@ -334,6 +387,7 @@
 BOOL handleDialysateDeliveryRequestMsg( MESSAGE_T *message )
 {
     BOOL result = FALSE;
+    REQUEST_REJECT_REASON_CODE_T fpReason = REQUEST_REJECT_REASON_NONE;
 
     if ( message->hdr.payloadLen == sizeof( DIALYSATE_DELIVERY_REQ_PAYLOAD_T ) )
     {
@@ -343,7 +397,7 @@
         memcpy( &startTxRequest, message->payload, sizeof( DIALYSATE_DELIVERY_REQ_PAYLOAD_T ) );
 
         // Process the dialysate delivery request message
-        if ( ( DD_MODE_STAN == ddMode ) && ( TRUE == startTxRequest.start ) )
+        if ( ( DD_MODE_PREG == ddMode ) && ( TRUE == startTxRequest.start ) )
         {
             // Set dialysate flow rate, UF rate and dialysate temperature
             setTDDialysateFlowrate( startTxRequest.dialRate );
@@ -355,14 +409,16 @@
             setTDDialyzerBypass( startTxRequest.bypassDialyzer );
 
             // start dialysate generation
-            result = requestDDStart();
+            result = requestDDGenDialStart();
         }
         else if ( DD_MODE_GEND == ddMode )
         {
             if ( FALSE == startTxRequest.start )
             {
-                // stop dialysate generation by transitioning to standby mode
-                requestNewOperationMode( DD_MODE_STAN );
+                // stop dialysate generation
+                result = requestDDGenDialyasteStop();
+                // stop FP Pre-Generate Permeate
+                fpReason = signalStopGenPermeate();
             }
             else
             {
@@ -376,10 +432,10 @@
                 setTDDialyzerBypass( startTxRequest.bypassDialyzer );
 
                 // Signal to update treatement parameters
-                setTreatementParamUpdate();
-            }
+                setTreatmentParamUpdate();
 
-            result = TRUE;
+                result = TRUE;
+            }
         }
     }