diff --git a/lib_xua/src/core/user/user_hid.h b/lib_xua/src/core/user/user_hid.h
index 6620c7dd..687b2445 100644
--- a/lib_xua/src/core/user/user_hid.h
+++ b/lib_xua/src/core/user/user_hid.h
@@ -2,14 +2,41 @@
 
 
 /* These defines relate to the HID report desc - do not mod */
-#define HID_CONTROL_PLAYPAUSE_SHIFT    0x00
-#define HID_CONTROL_NEXT_SHIFT 		   0x01
-#define HID_CONTROL_PREV_SHIFT		   0x02
-#define HID_CONTROL_VOLUP_SHIFT        0x03
-#define HID_CONTROL_VOLDN_SHIFT		   0x04
-#define HID_CONTROL_MUTE_SHIFT		   0x05
+#define HID_CONTROL_PLAYPAUSE_SHIFT  0x00
+#define HID_CONTROL_NEXT_SHIFT       0x01
+#define HID_CONTROL_PREV_SHIFT       0x02
+#define HID_CONTROL_VOLUP_SHIFT      0x03
+#define HID_CONTROL_VOLDN_SHIFT      0x04
+#define HID_CONTROL_MUTE_SHIFT       0x05
 
 #define HID_DATA_SIZE 1
 
-void UserReadHIDData(unsigned char hidData[HID_DATA_SIZE]);
+#ifndef HID_SIMULATE_INTERRUPTS
+#define HID_SIMULATE_INTERRUPTS 0
+#endif
 
+#ifndef INTERRUPT_ASSERT_LEVEL
+#define INTERRUPT_ASSERT_LEVEL 0
+#endif
+
+#if( 0 < HID_CONTROLS )
+
+#if( 0 < INTERRUPT_ASSERT_LEVEL )
+#define INT_ASSERT_LEVEL   1
+#define INT_DEASSERT_LEVEL 0
+#else
+#define INT_ASSERT_LEVEL   0
+#define INT_DEASSERT_LEVEL 1
+#endif
+
+#if( 0 < HID_SIMULATE_INTERRUPTS )
+#define HID_DEASSERT_COUNT       10000
+#define HID_INTERRUPT_COUNT 1000000000
+#endif
+
+select UserHIDTrigger( unsigned* hidValueLatched );
+void UserInitHIDData( void );
+void UserReadHIDData( unsigned char hidData[ HID_DATA_SIZE ]);
+void UserSetHIDData( const unsigned hidData );
+
+#endif /* ( 0 < HID_CONTROLS ) */
diff --git a/lib_xua/src/core/user/user_hid.xc b/lib_xua/src/core/user/user_hid.xc
deleted file mode 100644
index 4319bf43..00000000
--- a/lib_xua/src/core/user/user_hid.xc
+++ /dev/null
@@ -1,44 +0,0 @@
-// Copyright (c) 2019, XMOS Ltd, All rights reserved
-#include <stdint.h>
-#include <limits.h>
-#include <xs1.h>
-#include "user_hid.h"
-
-#define HID_DEASSERT_COUNT    10000000
-#define HID_INTERRUPT_COUNT 1000000000
-#define HID_REPORT_DATA 0x01
-
-static unsigned char initialised = 0;
-
-static unsigned int curr_time  = 0;
-static unsigned int last_time  = 0;
-static unsigned int tick_count = 0;
-
-void UserReadHIDData( unsigned char hidData[ HID_DATA_SIZE ])
-{
-  timer tmr;
-
-  if( !initialised ) {
-    tmr :> last_time;
-    initialised = 1;
-  } else {
-    tmr :> curr_time;
-    tick_count += ( last_time < curr_time ) ? curr_time - last_time : curr_time + ( UINT_MAX - last_time );
-
-    if(( HID_INTERRUPT_COUNT <= tick_count ) && ( tick_count <= ( HID_INTERRUPT_COUNT + HID_DEASSERT_COUNT ))) {
-      for( unsigned idx = 0; idx < HID_DATA_SIZE; ++idx ) {
-        hidData[ idx ] = HID_REPORT_DATA;
-      }
-    } else {
-      for( unsigned idx = 0; idx < HID_DATA_SIZE; ++idx ) {
-        hidData[ idx ] = 0x00;  
-      }
-
-      if (( HID_INTERRUPT_COUNT + HID_DEASSERT_COUNT ) <= tick_count ) {
-        tick_count = 0;
-      }
-    }
-
-    last_time = curr_time;
-  }
-}