Index: firmware/App/Controllers/Buttons.c
===================================================================
diff -u -rc0273c73da6b6dee4ad6f1d54cb6c6f27a262b5b -r8fdca8ef380555c6c93e30b517258988333ffd89
--- firmware/App/Controllers/Buttons.c	(.../Buttons.c)	(revision c0273c73da6b6dee4ad6f1d54cb6c6f27a262b5b)
+++ firmware/App/Controllers/Buttons.c	(.../Buttons.c)	(revision 8fdca8ef380555c6c93e30b517258988333ffd89)
@@ -56,10 +56,11 @@
 } OFF_BUTTON_RSP_T;
 
 #define OFF_REQUEST_PULSE_COUNT         4
-#define OFF_REQUEST_PULSE_INTVL         50      // ms
-#define STOP_BUTTON_PENDING_TIMEOUT     500     // ms
-#define STUCK_BUTTON_TIMEOUT            1000    // ms
-#define OFF_REQUEST_EXPIRATION_TIME     (1000 * 60)  // ms (1 minute)
+#define OFF_REQUEST_PULSE_INTVL_MS      50      // ms
+#define OFF_REQUEST_DELAY_TIME_MS       2000    // ms
+#define STOP_BUTTON_PENDING_TIMEOUT_MS  500     // ms
+#define STUCK_BUTTON_TIMEOUT_MS         1000    // ms
+#define OFF_REQUEST_EXPIRATION_TIME_MS  (1000 * 60)  // ms (1 minute)
 
 #define USER_CONFIRMED                  1
 #define USER_REJECTED                   0
@@ -72,7 +73,8 @@
 static U32 offRequestPendingTimer = 0;
 static BOOL offButtonPressPending = FALSE;
 static U32 offRequestPulseCount = 0;
-static U32 offRequestPulseTimer = 0;
+static U32 offRequestPulseTimer = 0;
+static U32 offRequestDelayTimer = 0;
 
 DATA_DECL( BUTTON_STATE_T, StopButtonState, dataStopButtonState, BUTTON_STATE_RELEASED, BUTTON_STATE_PRESSED );
 static BUTTON_STATE_T prevStopButtonState = BUTTON_STATE_RELEASED;
@@ -211,7 +213,7 @@
                 buttonSelfTestState = BUTTON_SELF_TEST_STATE_COMPLETE;
                 result = SELF_TEST_STATUS_PASSED;
             }
-            else if ( TRUE == didTimeout( buttonSelfTestTimerCount, STUCK_BUTTON_TIMEOUT ) )
+            else if ( TRUE == didTimeout( buttonSelfTestTimerCount, STUCK_BUTTON_TIMEOUT_MS ) )
             {
                 U32 almData = ( dataStopButtonState.data == BUTTON_STATE_PRESSED ? BUTTON_STOP : BUTTON_OFF );
 
@@ -361,7 +363,7 @@
     if ( TRUE == offRequestAwaitingUserConfirmation )
     {
         offRequestPendingTimer += TASK_PRIORITY_INTERVAL;
-        if ( offRequestPendingTimer >= OFF_REQUEST_EXPIRATION_TIME )
+        if ( offRequestPendingTimer >= OFF_REQUEST_EXPIRATION_TIME_MS )
         {
             offRequestAwaitingUserConfirmation = FALSE;
             sendOffButtonMsgToUI( OFF_BUTTON_CMD_CANCEL_USER_CONFIRM_PROMPT );
@@ -370,17 +372,23 @@
 
     // if user confirmed off button press, manage off request sequence
     if ( TRUE == offButtonPressPending )
-    {
-        offRequestPulseTimer += TASK_PRIORITY_INTERVAL;
-        if ( offRequestPulseTimer >= OFF_REQUEST_PULSE_INTVL )
-        {
-            offRequestPulseTimer = 0;
-            offRequestPulseCount--;
-            if ( offRequestPulseCount == 0 )
-            {
-                offButtonPressPending = false;
-            }
-            toggleCPLDOffRequest();
+    {
+        // delay power off to provide sub-systems time to prepare for shutdown
+        offRequestDelayTimer += TASK_PRIORITY_INTERVAL;
+        if ( offRequestDelayTimer >= OFF_REQUEST_DELAY_TIME_MS )
+        {
+            // power off sequence is 4 50 ms toggles of the off request output signal
+            offRequestPulseTimer += TASK_PRIORITY_INTERVAL;
+            if ( offRequestPulseTimer >= OFF_REQUEST_PULSE_INTVL_MS )
+            {
+                offRequestPulseTimer = 0;
+                offRequestPulseCount--;
+                if ( offRequestPulseCount == 0 )
+                {
+                    offButtonPressPending = false;
+                }
+                toggleCPLDOffRequest();
+            }
         }
     }
 }
@@ -412,7 +420,7 @@
     if ( TRUE == stopButtonPressPending )
     {
         // if stop button not consumed within a reasonable time, s/w fault
-        if ( TRUE == didTimeout( stopButtonPendingTimer, STOP_BUTTON_PENDING_TIMEOUT ) )
+        if ( TRUE == didTimeout( stopButtonPendingTimer, STOP_BUTTON_PENDING_TIMEOUT_MS ) )
         {
             stopButtonPressPending = FALSE;
             SET_ALARM_WITH_1_U32_DATA( ALARM_ID_HD_SOFTWARE_FAULT, SW_FAULT_ID_BUTTONS_STOP_BUTTON_NOT_CONSUMED )