#error USB_HOST_ONLY is not available for the currently selected USB AVR model.\r
                                #endif\r
                                \r
-                               #define USB_DEVICE_ONLY\r
+                               #if !defined(USB_DEVICE_ONLY)\r
+                                       #define USB_DEVICE_ONLY\r
+                               #endif\r
                        #endif\r
 \r
                        #if (!defined(USB_DEVICE_ONLY) && !defined(USB_HOST_ONLY))\r