Index: firmware/App/Services/FPGA.c
===================================================================
diff -u -rce596a29a2bd6384d70b2fe7b9c332b0f1f37a84 -rfbb180e9b4830dd5f890f4f33f022ce375ff4012
--- firmware/App/Services/FPGA.c	(.../FPGA.c)	(revision ce596a29a2bd6384d70b2fe7b9c332b0f1f37a84)
+++ firmware/App/Services/FPGA.c	(.../FPGA.c)	(revision fbb180e9b4830dd5f890f4f33f022ce375ff4012)
@@ -103,6 +103,8 @@
 #define FRONT_DOOR_SWITCH_MASK          0x0010                  ///< Front door switch bit mask. Bit 4 of the GPIO register.
 #define PUMP_TRACK_SWITCH_MASK          0x0020                  ///< Pump track switch bit mask. Bit 5 of the GPIO register.
 
+#define FPGA_BACKUP_ALARM_AUDIO_CONVERT 0.4                     ///< Converts backup (piezo) alarm audio ADC volts to amps.
+
 // FPGA Sensors Record
 #pragma pack(push,1)
 /// Record structure for FPGA header read.
@@ -180,13 +182,13 @@
     S16 VBVPosition;                            ///< Reg 360.  Encoder position from VBV pinch valve.  0 until PID interface is enabled.
     S16 VDiPosition;                            ///< Reg 362.  Encoder position from VDi pinch valve.  0 until PID interface is enabled.
     S16 VDoPosition;                            ///< Reg 364.  Encoder position from VDo pinch valve.  0 until PID interface is enabled.
-    S16 VSparePosition;                         ///< Reg 366.  Encoder position from VSpare pinch valve.  0 until PID interface is enabled.
+    S16 fpgaIntVoltage;                         ///< Reg 366.  Internal FPGA Vcc voltage.  3V range over 12 bits (0..4095).
     U16 valveStatus;                            ///< Reg 368.  Valve status register.
     U16 VBAPWMTarget;                           ///< Reg 370.  PWM target duty cycle for VBA pinch valve.
     U16 VBVPWMTarget;                           ///< Reg 372.  PWM target duty cycle for VBV pinch valve.
     U16 VDiPWMTarget;                           ///< Reg 374.  PWM target duty cycle for VDi pinch valve.
     U16 VDoPWMTarget;                           ///< Reg 376.  PWM target duty cycle for VDo pinch valve.
-    U16 VSparePWMTarget;                        ///< Reg 378.  PWM target duty cycle for Vspare pinch valve.
+    U16 VSparePWMTarget;                        ///< Reg 378.  Internal FPGA Vcc Aux voltage.
     U08 syringePumpStatus;                      ///< Reg 380.  Syringe pump status register.
     U08 syringePumpADCReadCounter;              ///< Reg 381.  Syringe pump ADC read counter.
     U08 syringePumpADCandDACStatus;             ///< Reg 382.  Syringe pump ADC and DAC status register.
@@ -206,7 +208,8 @@
     U16 VDiCurrent;                             ///< Reg 410.  VDi pinch valve current (Register VAUX11)
     U16 VSpareSpeed;                            ///< Reg 412.  VSpare speed (Register VAUX5)
     U16 VSpareCurrent;                          ///< Reg 414.  VSpare current (Register VAUX13)
-    U16 fpgaTimerCount_ms;                      ///< Reg 416.  Internal FPGA timer count in ms.
+    U16 fpgaTimerCount_ms;                      ///< Reg 416.  Free running 1ms timer counter.  Rolls over at 65535.Internal FPGA timer count in ms.
+    U16 backupAlarmAudioPeakCurrent;            ///< Reg 418.  Piezo alarm peak ADC current in previous 10ms.  12 bit unsigned.
 } FPGA_SENSORS_T;
 
 /// Record structure for FPGA continuous priority writes.
@@ -1843,6 +1846,22 @@
 
 /*********************************************************************//**
  * @brief
+ * The getFPGABackupAlarmAudioCurrent function gets the latest piezo alarm
+ * audio current reading.
+ * @details Inputs: fpgaSensorReadings
+ * @details Outputs: none
+ * @return Latest piezo alarm audio current reading
+ *************************************************************************/
+F32 getFPGABackupAlarmAudioCurrent( void )
+{
+    U16 adcCnts = fpgaSensorReadings.backupAlarmAudioPeakCurrent;
+    F32 result  = ( ( (F32)adcCnts / (F32)BITS_12_FULL_SCALE ) * FPGA_BACKUP_ALARM_AUDIO_CONVERT ) * (F32)MA_PER_AMP;
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
  * The getFPGAAirTrapLevels function gets the latest air trap level sensor
  * readings.
  * @details Inputs: fpgaSensorReadings