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Are inherited connections supported by layout XL

RVERP

Hello,

I have a problem with inherited connections of the schematic. I have an inverter using an inherited connection for vdd and vss. The correct netname is assigned by setting a user property. This assigned netname however is not propagated to the layout. The CDL netlist generated from the schematic is correct, so it looks like the problem is only with XL.

In layout the generic net name is assigned to the pin (e.g. VDD_33!).

Is there something wrong wrong, or is it just not supported?

  • Andrew Beckett

    Yes, inherited connections are supported by VLS XL. The recommendation is (for inherited connections as a whole) to use "explicit" inherited connections (i.e. use pins on the schematic with netExpr on them rather than just netExpr on wires; you can still omit the pins on the symbols) as this way the pin names on the blocks are well defined.

    It's unclear to me exactly what your example looks like, so perhaps you should contact customer support?

    Regards,

    Andrew.

  • drdanmc

    when you say "in layout the generic net name is assigned to the pin..." do you mean inside of the inverter layout or wires routing to that pin in the cell where the inverter is instantiated?  If the latter, you should see the correct connectivity on the wire.  If the former then that is normal because the inverter by itself doesn't know about netsets applied to instances of the inverter.

  • RVERP

    Hello All,

    Thanks for the replies, but I found what was going wrong. My layout with the inherited supply did not have a net expression defined. Doing this solved the problem.

  • RVERP

    Hello All,

    Thanks for the replies, but I found what was going wrong. My layout with the inherited supply did not have a net expression defined. Doing this solved the problem.

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