Index: firmware/App/Drivers/SafetyShutdown.c
===================================================================
diff -u -rb64c49fdcf2b6d95e61e63f8e258c4e600935bbd -r216bd924f989182e648ee5f33f4c91c43ac438ac
--- firmware/App/Drivers/SafetyShutdown.c	(.../SafetyShutdown.c)	(revision b64c49fdcf2b6d95e61e63f8e258c4e600935bbd)
+++ firmware/App/Drivers/SafetyShutdown.c	(.../SafetyShutdown.c)	(revision 216bd924f989182e648ee5f33f4c91c43ac438ac)
@@ -14,19 +14,17 @@
  *
  **************************************************************************/
 
-#include "gio.h"
+#include "mibspi.h"
 
 #include "SafetyShutdown.h"
 
 // ********** 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 )
-
 /*************************************************************************
  * @brief initSafetyShutdown
  * The initSafetyShutdown function initializes the Buttons module.