Index: firmware/App/Services/FpgaDD.c
===================================================================
diff -u -r1c478c1aff953528127767db1f4f747a7f7089c8 -r35ccc443e6440d79231ab4a3951bebc0e9789b68
--- firmware/App/Services/FpgaDD.c	(.../FpgaDD.c)	(revision 1c478c1aff953528127767db1f4f747a7f7089c8)
+++ firmware/App/Services/FpgaDD.c	(.../FpgaDD.c)	(revision 35ccc443e6440d79231ab4a3951bebc0e9789b68)
@@ -8,8 +8,8 @@
 *
 * @file    FpgaDD.c
 *
-* @author  (last)      Sameer Kalliadan Poyil
-* @date    (last)      16-Apr-2026
+* @author  (last)      Michael Garthwaite
+* @date    (last)      09-Jun-2026
 *
 * @author  (original)  Vinayakam Mani
 * @date    (original)  26-Aug-2024
@@ -317,7 +317,7 @@
     U16 fpgaD18PresTemp;                        ///< Reg 534. D18 MPM pressure sensor RAW temperature data
     U16 fpgaD41PresPressure;                    ///< Reg 536. D41 MPM pressure sensor RAW pressure data
     U16 fpgaD41PresTemp;                        ///< Reg 538. D41 MPM pressure sensor RAW temperature data
-    U32 fpgaAvailableRegister1;                 ///< Reg 540. Available register 1
+    U32 fpgaD92SpeedCnt;                        ///< Reg 540. D92 Substitution Pump Hall sensor speed counter.
     U08 fpgaHallSensInputs;                     ///< Reg 544. Hall sensor Inputs
     U08 fpgaD42TxFIFOCnt;                       ///< Reg 545. Blood leak sensor transmit FIFO count
     U16 fpgaD42RxErrorCnt;                      ///< Reg 546. Blood leak sensor Receive error count
@@ -1421,6 +1421,7 @@
 {
     fpgaActuatorSetPoints.fpgaD92PumpRevCount = count;
 }
+
 /*********************************************************************//**
  * @brief
  * The setFPGAD5HeaterOnOffControl function sets the primary heater
@@ -4001,4 +4002,17 @@
     return fpgaSensorReadings.fpgaP18CalMemCounter;
 }
 
+/*********************************************************************//**
+ * @brief
+ * The getFPGAD92PumpHallSenseCount function gets substitution pump, D92,
+ * hall sensor speed counter.
+ * @details \b Inputs: fpgaD92SpeedCnt
+ * @details \b Outputs: none
+ * @return substitution pump hall sense pulse width
+ *************************************************************************/
+U32 getFPGAD92PumpHallSenseCount( void )
+{
+    return fpgaSensorReadings.fpgaD92SpeedCnt;
+}
+
 /**@}*/