Index: firmware/App/Drivers/PressureSensor.c
===================================================================
diff -u -ra9c88c428c6ab7e9bdaa273826c1fde1b0a8a1f5 -rbd37ce75271151436de0bb6de9f75123d8251396
--- firmware/App/Drivers/PressureSensor.c	(.../PressureSensor.c)	(revision a9c88c428c6ab7e9bdaa273826c1fde1b0a8a1f5)
+++ firmware/App/Drivers/PressureSensor.c	(.../PressureSensor.c)	(revision bd37ce75271151436de0bb6de9f75123d8251396)
@@ -29,11 +29,11 @@
 
 // ********** private definitions **********
 
-#define BAR_TO_MMHG                                 ( 750.062F )                            ///< Conversion factor for converting bar to mmHg.
-
 #define PRES_SENSORS_ZERO_OFFSET                    ( 1638.0F )                             ///< Zero offset for pressure sensor readings.
 #define PRES_SENSORS_DIVISOR                        ( 14745.0F - PRES_SENSORS_ZERO_OFFSET ) ///< Divisor for pressure sensor conversion from counts to bars.
-#define PRES_SENSORS_RANGE_IN_BARS                  ( 1.6F - 0.0F )                         ///< Range (in bars) of the pressure sensors (0..1.6).
+#define PRESSURE_MIN_PSI                            ( -30.0F )                              ///< Minimum of scale for pressure sensor reading (in PSI).
+#define PRESSURE_MAX_PSI                            ( 30.0F )                               ///< Maximum of scale for pressure sensor reading (in PSI).
+#define PSI_TO_MMHG                                 ( 51.7149F )                            ///< Conversion factor for converting PSI to mmHg.
 
 #define PRES_SENSORS_COUNT_ERROR_TIMEOUT_MS         ( 2 * MS_PER_SECOND )                   ///< Pressure sensors read and error count timeout in milliseconds.
 
@@ -57,8 +57,7 @@
 // ********** private function prototypes **********
 
 static void checkPressureSensors( void );
-static F32 convertPressureRdg2mmHg( S16 counts );
-static F32 getPresureReadingFromFPGARegReading( U16 fpgaReg );
+static F32 convertPressureRdg2mmHg( U16 counts );
 static U32 getPressureStatusFromFPGARegReading( U16 fpgaReg );
 
 /*********************************************************************//**
@@ -153,36 +152,21 @@
  * @param counts the raw pressure reading in counts from the FPGA
  * @return the pressure in mmHg
  *************************************************************************/
-static F32 convertPressureRdg2mmHg( S16 counts )
+static F32 convertPressureRdg2mmHg( U16 counts )
 {
-    F32 rdg  = getPresureReadingFromFPGARegReading( counts );
-    F32 bar  = ( ( rdg - PRES_SENSORS_ZERO_OFFSET ) * ( PRES_SENSORS_RANGE_IN_BARS ) / ( PRES_SENSORS_DIVISOR ) );
-    F32 mmHg = bar * BAR_TO_MMHG;
+    S16 rdg  = (S16)( counts & FPGA_PRESSURE_READING_BITS_MASK );
+    F32 presPSI;
+    F32 mmHg;
 
+    // If the arterial pressure status is normal, convert the counts to pressure in mmHg
+    presPSI = ( ( (F32)rdg - PRES_SENSORS_ZERO_OFFSET ) *( PRESSURE_MAX_PSI - PRESSURE_MIN_PSI ) / PRES_SENSORS_DIVISOR ) + PRESSURE_MIN_PSI;
+    mmHg    = presPSI * PSI_TO_MMHG;
+
     return mmHg;
 }
 
 /*********************************************************************//**
  * @brief
- * The getPresureReadingFromFPGARegReading function extracts the signed
- * pressure reading (in counts) from the FPGA register reading.
- * @details \b Inputs: none
- * @details \b Outputs: none
- * @param fpgaReg the value read from the FPGA register
- * @return the pressure portion of the FPGA register value, sign extended
- *************************************************************************/
-static F32 getPresureReadingFromFPGARegReading( U16 fpgaReg )
-{
-//    U16 rdg = fpgaReg & FPGA_PRESSURE_READING_BITS_MASK;                    // mask off status bits
-//    S16 ext = signExtend16( rdg, FPGA_PRESSURE_READING_BIT_COUNT - 1 );     // sign extend reading in case it's negative
-//
-//    return (F32)ext;
-    // TODO - fix sign extension
-    return (F32)((S16)fpgaReg);
-}
-
-/*********************************************************************//**
- * @brief
  * The getPressureStatusFromFPGARegReading function extracts the status
  * from the FPGA register reading.
  * @details \b Inputs: none