[oc] =?gb2312?B?tPC4tDogW29jXSBtaXNjIGRpcmVjdG9yeQ==?=

[lin.sheng@mail.zte.com.cn]

Hi, Blue Beaver,
  I don't understand how the synchronizer_flop works. It seems just like a
common D type flip-flop with asynchronous reset. After synthesis, it must
also be implemented by the D type flip-flop from the target library. How
could it avoid the X in the gate-level simulation? Can you explain for me?

Best Regards!
Lin Sheng



                                                                                             
                    "llbutcher"                                                              
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                    owner-cores@ope        主题：  [oc] misc directory                       
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                    01-09-07 16:17                                                           
                    请答复 给 cores                                                          
                                                                                             
                                                                                             




I have created a CVS source directory called "misc".

I hope that this directory can be used for files which are
of general interest, but which contain IP which is too
small to be considered a project by itself.

This IP might be interesting either because it is used as
a component in many other IP's, or because it shows
how to do a common function.


For example, I have added a copy of the verilog version of
a prototype Opencores Copyright Notice to "misc".

I have also put in a very simple synchronizer_flop.v.  I hope
that opencores users will manually instantiate this flop in
designs where a signal must cross between clock domains.
If this flop is used consistently, we will be able to do gate-level
simulation with a special simulation model which does not
make "X"s when the flop has setup or hold violations.


The "misc" directory is intended to be used by many people.
Individual files are likely to be edited by many people, too.

If you have a good idea for a simple interesting module to place
there, or know how to improve a module which is already there,
go ahead.

When done, consider adding a short description of your
contribution to the Readme file.  Good luck!


Blue Beaver



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