Index: firmware/App/Services/FPGA.c
===================================================================
diff -u -r44a100f8e5210a02c23b8fcc4527d8e96d577381 -r765a17e8b525704386d48df1431688b07b785b40
--- firmware/App/Services/FPGA.c	(.../FPGA.c)	(revision 44a100f8e5210a02c23b8fcc4527d8e96d577381)
+++ firmware/App/Services/FPGA.c	(.../FPGA.c)	(revision 765a17e8b525704386d48df1431688b07b785b40)
@@ -100,6 +100,8 @@
 
 #define FPGA_ALARM_AUDIO_VOLUME_SHIFT   3                       ///< Shift alarm audio volume 3 bits to left before writing to 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.
@@ -177,13 +179,13 @@
     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.
@@ -204,6 +206,7 @@
     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 backupAlarmAudioPeakCurrent;            ///< Reg 418.  Piezo alarm peak ADC current in previous 10ms.  12 bit unsigned.
 } FPGA_SENSORS_T;
 
 /// Record structure for FPGA continuous priority writes.
@@ -1824,6 +1827,22 @@
 
 /*********************************************************************//**
  * @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