1 Reply Latest reply on Oct 25, 2013 4:30 PM by dan_liddell

    layout port name conflict

    mugofgold

      Hi,

       

      I am having schematic with vss/vdd (lower-case) pwr/gnd pins and also defined in the layout as lower-case pins only. But somehow Calibre is converting the layout pins to upper-case and unless I use "SOURCE CASE NO" it's not passing.

       

      I am having some standard cells in this cell and they have these pins defined (at the lower  hierarchy) in upper case.

       

      But I don't want to use this option (at least for now!!). Is there a way that I could get a clean LVS?

      --------------------------------------------------------------------------------

       

      Net VDD                                                   VDD

      --------------------------                                --------------------------

       

      xxxxxx:neg                                    ** missing connection **

      xxxxxx

       

      Net VSS                                                   VSS

      --------------------------                                --------------------------

       

      xxxxxx:BULK                               ** missing connection **

      xxxxxx

       

      ** no similar net **                                      vdd

      ** no similar net **                                      vss

       

      ------------------------------------------------------------------------------------

      From the summary file:

       

         3 layout nets had all their pins removed and were deleted.

       

       

      o Initial Correspondence Points:

       

         Ports:        vdd vss

      ------------------------------------------------------------------------------------

      From the transcript:

      --------------------------------------------------------------------------------

      -----                                PORTS                                 -----

      --------------------------------------------------------------------------------

       

      vss (4.21,26.945) 133 cell1          vdd (5.655,26.975) 133 cell1

       

      VSS (0.07,0) 132 cell2           VDD (0.07,1.68) 132 cell2

      VDD (0.07,1.68) 132 cell5         ZN (0.49,0.84) 131 cell5

      I (0.21,0.56) 132 cell6           ZN (0.77,0.84) 131 cell6

      VSS (0.07,0) 132 cell7            VDD (0.07,1.68) 132 cell7

      VSS (0.07,0) 132 cell8            I (0.07,0.84) 131 cell8

      VDD (0.07,1.68) 132 cell8         ZN (0.35,0.84) 131 cell8

      VSS (0.07,0) 132 cell9          VDD (0.07,1.68) 132 cell9

      BULK (0.17,1.91) 131 cell10

      MINUS (2.34,0.18) 133 cell10

      PLUS (2.34,3.64) 131 cell10

        • 1. Re: layout port name conflict
          dan_liddell

          Hi,

           

          You should only use LAYOUT CASE or SOURCE CASE YES if netlist object names that differ *only by text case* are, in fact, different objects. So, for example, if vdd and VDD are truly different nets, then you have to treat that netlist with case-sensitive parsing by setting the proper command to YES. If you have no objects that are logically different based on text case alone, then both of the preceding commands should be set to NO, which is the default.

           

          Case-sensitive comparison of layout to source is a different matter. Calibre doesn't compare layout to source in a case-sensitive manner unless you say LVS COMPARE CASE YES. If that is set, then vdd in layout will not match VDD in the source. If NO (default) is set, then they will match.

           

          Do this:

           

          grep -i "lvs compare case" lvs_report

           

          If the setting is YES, you may want to set that to NO. If it already is NO, then it sounds like your nets that differ by case are logically different nets.

           

          For a complete discussion of this topic, refer to "Case-Sensitive Handling of Netlists" in the Calibre Verification User's Manual.

           

          dan

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