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SpiceIn fails for existing symbol with bus pins

FormerMember
FormerMember

Hello,

I have SPICE netlist (also tried with CDL and spectre) with some digital gates and bus inputs/outputs, which I want to import into an existing cell. I activated the option for merging bus bits and if I do the import into an empty cell, it works fine.

Unfortunately, the CDL import, which allows specifying the pin direction in the netlist, does not find my existing cells (already asked about it in Import Netlist to Schematic with existing Cells in other Libraries ). For non-CDL netlists the pin directions are take from a symbol view, if existent. However, the import fails if the symbol contains busses with the message "Mismatch in number of ports of  symbol and subcircuit" It seems the importer does not recognize the merged pins.

I also tried to import the netlist twice. First, to generate a symbol with busses (which works) and then a second time (after deleting the schematic and without overwrite option), which fails with the message above. Also, if the override option is active, every existing view in the cell is deleted.

The only way I could get it to work is to import the netlist into a dummy cell, assign the correct pin directions and copy it to the destination cell.

Is there a way to get the import running with existing symbols and busses?

Parents

  • Hi Paul,

    I just played with this, and I agree, it's not working very well. The merge busbits capability is fairly new (I think it was only exposed by default in IC618 ISR11), and when I tried it even without an existing symbol it appeared to be breaking the connectivity in my case. If you then try to use an existing symbol with bus pins, it fails in the way that you mention (so I suspect that hasn't been taken into account in the code).

    You should contact customer support - best to get this to R&D with a real-life subckt rather than something that I just made up for testing purposes (plus it always helps to have a real customer behind the issue).

    Thanks

    Andrew

Reply

  • Hi Paul,

    I just played with this, and I agree, it's not working very well. The merge busbits capability is fairly new (I think it was only exposed by default in IC618 ISR11), and when I tried it even without an existing symbol it appeared to be breaking the connectivity in my case. If you then try to use an existing symbol with bus pins, it fails in the way that you mention (so I suspect that hasn't been taken into account in the code).

    You should contact customer support - best to get this to R&D with a real-life subckt rather than something that I just made up for testing purposes (plus it always helps to have a real customer behind the issue).

    Thanks

    Andrew

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