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 Extract netlist from layout 

Last post Fri, Dec 21 2007 2:49 AM by archive. 2 replies.
Started by archive 21 Dec 2007 02:49 AM. Topic has 2 replies and 3515 views
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  • Fri, Dec 21 2007 2:49 AM

    • archive
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    Extract netlist from layout Reply

    Hello all,

    I am a digital design engineer and am trying to simulate power up/down behavior of a small system using Virtuoso.
    The flow I followed: make a 32-bit adder in VHDL, synthesize the design using RTLCompiler, place&route using Encounter, extract GDSII with Encounter (including the GDSII of the standard cells used). Next I import the GDSII in Virtuso and I can see the layout.

    What I would now want to do is to simulate the design using the Virtuso Analog Environment and see how much current is going into the vdd of the design when switching power. For doing this I got told that you first need a netlist of the whole design, and this is where I got stuck. I can extract the netlist of the adder from Encounter, but I don't have the schematics of my standard cells.

    On http://www.iaik.tugraz.at/teaching/05_vlsi-design/manual/netlist_extraction/index.php a method is explained to extract the netlist from layout using Diva. For this a rule file is required, but when checking the foundry website the rule files for diva are only available for older technologies. Rule files for Assura available, but when I try to use the extarct.rul file in that package in Diva I get a bunch of errors on the file syntax.

    Is it possible to extract the netlist using Assura?
    Or do you know if it is possible to convert an Assura extract rules file to a Diva extract rules file?

    Thanks,

    Michael


    Originally posted in cdnusers.org by denil
    • Post Points: 0
  • Fri, Dec 21 2007 7:20 AM

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    RE: Extract netlist from layout Reply

    Hello all,

    I just found the following on http://www.chiptalk.org/modules/newbb/viewtopic.php?viewmode=flat&topic_id=63&forum=2:

    you can extract the netlist in the DF-II layout editor, Virtuoso. You can use either Diva or Assura. For Diva, use "Verify -> Extract". For Assura you need to set the "ASSURAHOME" environment variable. Then you will get an Assura menu in Virtuoso. Then you run "Assura -> LVS" followed by "Assura -> RCX".

    You should have either Diva or Assura decks for your process from the foundry. Choose which ever tool your foundry supports.


    Somewhere else (lost the link), it is stated that a schematic with only the pins has to be created first. Then Assura should be able to add the other components to the netlist.

    The problem I have now is that I get the following error when I try to do an LVS check:
    Compiling rules...

    error:  Unknown input 'by' found in geomStamp().
        Valid keywords are :
          'error', 'buttOrOver', 'floating', 'multStamp', 'multConnect', 'majority'.
    error:  Unknown input 'nplug' found in geomStamp().
        Valid keywords are :
          'error', 'buttOrOver', 'floating', 'multStamp', 'multConnect', 'majority'.
    ...

    When I check the extract rules file, the error seems to be generated by lines which look like this:

        geomStamp( nxwell tndiff by nplug )

    It looks like the "by nplug" cannot be parsed using my version of Assura (3.1.4).
    The extract rules file states that it is developed and QA under Assura version 3.1.7.

    Does anyone know if I can rewrite the lines with things like geomStamp( nxwell tndiff by nplug ) ?
    As put in the last post, I am a digital designer, so forgive me if this is trivial ;-)

    Thanks,

    Michael


    Originally posted in cdnusers.org by denil
    • Post Points: 0
  • Wed, Jan 2 2008 8:36 AM

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    RE: Extract netlist from layout Reply

    Hello all,

    I just tried using Assura 3.1.6, but still get the same syntax errors.
    Sourcelink however contains a describtion of the new syntax (with 'by') and an example of how to write the same in old syntax: http://sourcelink.cadence.com/docs/files/Release_Info/Docs/assuracommandref/assuracommandref3.1.7/comref_LVS.html#991272

    I will try to rewrite the extract rules file and hope that this is the only difference in syntax :-)

    Cheers,

    Michael


    Originally posted in cdnusers.org by denil
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Started by archive at 21 Dec 2007 02:49 AM. Topic has 2 replies.