Index: firmware/App/Controllers/SubstitutionPump.c
===================================================================
diff -u -r3b64586791accd0b9e8d8978b40e2509bb86dfbe -r69b6a8036f72eeb935a20701c7d30d402a9ba1f5
--- firmware/App/Controllers/SubstitutionPump.c	(.../SubstitutionPump.c)	(revision 3b64586791accd0b9e8d8978b40e2509bb86dfbe)
+++ firmware/App/Controllers/SubstitutionPump.c	(.../SubstitutionPump.c)	(revision 69b6a8036f72eeb935a20701c7d30d402a9ba1f5)
@@ -63,19 +63,24 @@
 #define MAX_ALLOWED_ML_OUT_OF_RANGE                          10                                                 ///< Maximum allowed mL/min out of range from target ml/min in open loop.
 #define RPM_OUT_OF_RANGE_TIME_OUT                            ( 2 * MS_PER_SECOND )                              ///< Open loop RPM out of range time out in ms.
 
-static const U32 SUBSTITUTION_PUMP_CONTROL_FORWARD = SUBSTITUTION_PUMP_CONTROL_SLEEP_OFF  |
-                                                    SUBSTITUTION_PUMP_CONTROL_NOT_RESET   |
-                                                    SUBSTITUTION_PUMP_CONTROL_ENABLE      |
-                                                    SUBSTITUTION_PUMP_CONTROL_REVERSE_DIR |
-                                                    SUBSTITUTION_PUMP_CONTROL_SIXTY_FOUR_STEP;
+//Stepper Motor driver configuration (DRV8434S)
+#define SUBSTITUTION_PUMP_CONTROL_DRV_SIXTY_FOUR_STEP        0x08                                               ///< 1/64 step, MS[3:0]=1000. (DRV8434S)
+#define SUBSTITUTION_PUMP_CONTROL_DRV_REVERSE_DIR            0x00                                               ///< bit 4 = DIR, Substitution pump reverse direction configuration.
+#define SUBSTITUTION_PUMP_CONTROL_DRV_FORWARD_DIR            0x10                                               ///< bit 4 = DIR, Substitution pump forward direction configuration.
+#define SUBSTITUTION_PUMP_CONTROL_DRV_ENABLE                 0x00                                               ///< bit 5, Substitution pump control enable pump.
+#define SUBSTITUTION_PUMP_CONTROL_DRV_DISABLE                0x20                                               ///< bit 5, active low, disabled. (DRV8434S)
 
-static const U32 SUBSTITUTION_PUMP_CONTROL_STOP = SUBSTITUTION_PUMP_CONTROL_SLEEP_OFF  |
-                                                  SUBSTITUTION_PUMP_CONTROL_NOT_RESET   |
-                                                  SUBSTITUTION_PUMP_CONTROL_DISABLE     |
-                                                  SUBSTITUTION_PUMP_CONTROL_REVERSE_DIR |
-                                                  SUBSTITUTION_PUMP_CONTROL_SIXTY_FOUR_STEP;
+#define DRV8434S_CTRL1_DEFAULT                               0x00
+#define DRV8434S_CTRL2_DEFAULT                               0x8F
+#define DRV8434S_CTRL4_DEFAULT                               0x30
+#define DRV8434S_CTRL5_DEFAULT                               0x08
+#define DRV8434S_CTRL6_DEFAULT                               0x03
+#define DRV8434S_CTRL7_DEFAULT                               0x20
 
+static U32 SUBSTITUTION_PUMP_CONTROL_FORWARD;
+static U32 SUBSTITUTION_PUMP_CONTROL_STOP;
 
+
 /// Enumeration of Substitution pump states.
 typedef enum SubstituionPumpState
 {
@@ -150,6 +155,38 @@
     substitutionPumpDataPublishInterval.ovData       = 0;
     substitutionPumpDataPublishInterval.override     = OVERRIDE_RESET;
 
+    if ( TRUE == getTestConfigStatus( TEST_CONFIG_DD_ENABLE_DRV8434S_STEPPER_DRIVER ) )
+    {
+        SUBSTITUTION_PUMP_CONTROL_FORWARD = SUBSTITUTION_PUMP_CONTROL_DRV_ENABLE |
+                                            SUBSTITUTION_PUMP_CONTROL_DRV_REVERSE_DIR |
+                                             SUBSTITUTION_PUMP_CONTROL_DRV_SIXTY_FOUR_STEP;
+
+        SUBSTITUTION_PUMP_CONTROL_STOP = SUBSTITUTION_PUMP_CONTROL_DRV_DISABLE |
+                                          SUBSTITUTION_PUMP_CONTROL_DRV_REVERSE_DIR |
+                                          SUBSTITUTION_PUMP_CONTROL_DRV_SIXTY_FOUR_STEP;
+
+        setFPGAD92CTRL1Reg( DRV8434S_CTRL1_DEFAULT );
+        setFPGAD92CTRL2Reg( DRV8434S_CTRL2_DEFAULT );
+        setFPGAD92CTRL4Reg( DRV8434S_CTRL4_DEFAULT );
+        setFPGAD92CTRL5Reg( DRV8434S_CTRL5_DEFAULT );
+        setFPGAD92CTRL6Reg( DRV8434S_CTRL6_DEFAULT );
+        setFPGAD92CTRL7Reg( DRV8434S_CTRL7_DEFAULT );
+    }
+    else
+    {
+        SUBSTITUTION_PUMP_CONTROL_FORWARD = SUBSTITUTION_PUMP_CONTROL_SLEEP_OFF |
+                                             SUBSTITUTION_PUMP_CONTROL_NOT_RESET |
+                                             SUBSTITUTION_PUMP_CONTROL_ENABLE |
+                                             SUBSTITUTION_PUMP_CONTROL_REVERSE_DIR |
+                                             SUBSTITUTION_PUMP_CONTROL_SIXTY_FOUR_STEP;
+
+        SUBSTITUTION_PUMP_CONTROL_STOP = SUBSTITUTION_PUMP_CONTROL_SLEEP_OFF |
+                                          SUBSTITUTION_PUMP_CONTROL_NOT_RESET |
+                                          SUBSTITUTION_PUMP_CONTROL_DISABLE |
+                                          SUBSTITUTION_PUMP_CONTROL_REVERSE_DIR |
+                                          SUBSTITUTION_PUMP_CONTROL_SIXTY_FOUR_STEP;
+    }
+
     initPersistentAlarm( ALARM_ID_DD_D92_PUMP_RPM_OUT_OF_RANGE, RPM_OUT_OF_RANGE_TIME_OUT, RPM_OUT_OF_RANGE_TIME_OUT );
 }