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Handling globals and inherited connections in LVS.

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I have a situation where there are several schematics with the same global signal name that is connected to separate power supplies at higher levels.  Assura gives me LVS errors, saying that the global nets should be connected in the layout.
I have tried using cdlGlobalMode = floating, but it does not change the result.  Anyone have any suggestions on how to handle this?
Thanks,
Larry


Originally posted in cdnusers.org by larryg3

  • How about:

    Select each schematic placement and add a NODESET property to each global net and give them unique names.

    -- Gerry


    Originally posted in cdnusers.org by vdvalk

  • We use this setup in our design shop all the time. For us, we use VDD! and VSS! for every schematic; however, we also tag a net expression to each of these nets in each schematic. (You only have to set the net expression on one wire in the schematic.) This allows us to redefine the globals VDD! and VSS! at a higher level of hierarchy using netSet properties on the higher level instances. And, we only have to do this one time, near the top, where multiple power planes exist in the same schematic.

    This gives us the best of both worlds: Flexible, portable schematics without power pins, and it's really easy once you get used to the idea.


    Originally posted in cdnusers.org by m27315

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