dft_async_input                                    Specifies the name of an
                                                   asynchronous signal.
 [ tree ]                                            Applies the constraint to
                                                     all levels of hierarchy
                                                     below the object(s)
                                                     specified.
 [ -scope ]                 scope                    module / current scope
 -input                     signal
 [ -level                   active_level ]           high, low /high
