static void USB_Device_ClearSetFeature(void);
 
                                #if !defined(NO_INTERNAL_SERIAL) && (USE_INTERNAL_SERIAL != NO_DESCRIPTOR)
-                                       static char USB_Device_NibbleToASCII(uint8_t Nibble) ATTR_ALWAYS_INLINE;
                                        static void USB_Device_GetInternalSerialDescriptor(void);
                                #endif
                        #endif