Index: firmware/App/Drivers/SafetyShutdown.c
===================================================================
diff -u -rb64c49fdcf2b6d95e61e63f8e258c4e600935bbd -rc081112c61e0d85854e8f1e604ac7f1f37c2ec02
--- firmware/App/Drivers/SafetyShutdown.c	(.../SafetyShutdown.c)	(revision b64c49fdcf2b6d95e61e63f8e258c4e600935bbd)
+++ firmware/App/Drivers/SafetyShutdown.c	(.../SafetyShutdown.c)	(revision c081112c61e0d85854e8f1e604ac7f1f37c2ec02)
@@ -1,4 +1,4 @@
-/**************************************************************************
+/**********************************************************************//**
  *
  *  Copyright (c) 2019-2020 Diality Inc. - All Rights Reserved.
  *
@@ -14,44 +14,130 @@
  *
  **************************************************************************/
 
-#include "gio.h"
+#include "mibspi.h"
 
+#include "SystemCommMessages.h"
 #include "SafetyShutdown.h"
 
+/**
+ *  @addtogroup SafetyShutdown
+ *  @{
+ */
+
 // ********** private definitions **********
 
-// GIO port A pin assignments for pins connected to CPLD
-#define SAFETY_GIO_PORT_PIN         3U
+// pin I/O macros
+#define SAFETY_SPI1_PORT_MASK       0x00000010  // (CS[4] - re-purposed as output GPIO)
+#define SET_SAFETY_SHUTDOWN()       {mibspiREG1->PC3 |= SAFETY_SPI1_PORT_MASK;}
+#define CLR_SAFETY_SHUTDOWN()       {mibspiREG1->PC3 &= ~SAFETY_SPI1_PORT_MASK;}
 
-// CPLD pin I/O macros
-#define SET_SAFETY_SHUTDOWN()       gioSetBit( gioPORTB, SAFETY_GIO_PORT_PIN, PIN_SIGNAL_HIGH )
-#define CLR_SAFETY_SHUTDOWN()       gioSetBit( gioPORTB, SAFETY_GIO_PORT_PIN, PIN_SIGNAL_LOW )
+// ********** private definitions **********
 
-/*************************************************************************
- * @brief initSafetyShutdown
- * The initSafetyShutdown function initializes the Buttons module.
+static BOOL safetyShutdownActivated = FALSE;            ///< Status of safety shutdown signal.
+static BOOL safetyShutdownOverrideResetState = FALSE;   ///< Natural status of safety shutdown signal.  Used to restore state on override reset.
+
+/*********************************************************************//**
+ * @brief
+ * The initSafetyShutdown function initializes the Safety Shutdown module.
  * @details
  * Inputs : none
  * Outputs : Safety Shutdown module signal output set to initial state.
- * @param none
  * @return none
  *************************************************************************/
 void initSafetyShutdown( void )
 {
     CLR_SAFETY_SHUTDOWN();
 }
 
-/*************************************************************************
- * @brief activateSafetyShutdown
+/*********************************************************************//**
+ * @brief
  * The activateSafetyShutdown function activates the safety shutdown signal.
  * @details
  * Inputs : none
  * Outputs : Safety Shutdown signal output set to active state.
- * @param none
  * @return none
  *************************************************************************/
 void activateSafetyShutdown( void )
 {
     SET_SAFETY_SHUTDOWN();
 }
 
+/*********************************************************************//**
+ * @brief
+ * The isSafetyShutdownActivated function returns whether the safety shutdown \n
+ * signal has been activated.
+ * @details
+ * Inputs : none
+ * Outputs : none
+ * @return safetyShutdownActivated
+ *************************************************************************/
+BOOL isSafetyShutdownActivated( void )
+{
+    return safetyShutdownActivated;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The testSetSafetyShutdownOverride function overrides the HD safety \n
+ * shutdown.
+ * @details
+ * Inputs : none
+ * Outputs : HD safety shutdown overridden
+ * @param value : TRUE to activate safety shutdown, FALSE to de-activate it.
+ * @return TRUE if override successful, FALSE if not
+ *************************************************************************/
+BOOL testSetSafetyShutdownOverride( U32 value )
+{
+    BOOL result = FALSE;
+
+    if ( TRUE == isTestingActivated() )
+    {
+        // remember natural state before override so we can reset
+        safetyShutdownOverrideResetState = safetyShutdownActivated;
+        // override safety shutdown signal
+        if ( value > 0 )
+        {
+            activateSafetyShutdown();
+        }
+        else
+        {
+            safetyShutdownActivated = FALSE;
+            CLR_SAFETY_SHUTDOWN();
+        }
+        result = TRUE;
+    }
+
+    return result;
+}
+
+/*********************************************************************//**
+ * @brief
+ * The testResetSafetyShutdownOverride function resets the override of the \n
+ * HD safety shutdown.
+ * @details
+ * Inputs : none
+ * Outputs : shutdown override reset
+ * @return TRUE if override reset successful, FALSE if not
+ *************************************************************************/
+BOOL testResetSafetyShutdownOverride( void )
+{
+    BOOL result = FALSE;
+
+    if ( TRUE == isTestingActivated() )
+    {
+        if ( TRUE == safetyShutdownOverrideResetState )
+        {
+            activateSafetyShutdown();
+        }
+        else
+        {
+            safetyShutdownActivated = FALSE;
+            CLR_SAFETY_SHUTDOWN();
+        }
+        result = TRUE;
+    }
+
+    return result;
+}
+
+/**@}*/