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Getting the list of metal layers connected to a selected metal layer

Mallikarjun032

Hi,

I have a layout having only ("M1" "drawing") metal layers, and for a metal layer given as input, I need to get the list all the metal layers which are connected and forming a single net with it.

I have checked using the 'dbGetOverlaps()' function, but this is not giving me the desired output, because this function returns the metal layers whose 'bBox's overlap with the 'bBox' of the selected metal layer. Although the 'bBox's overlap, they may not be connected.

Please let me know if there's a way to get the list of all the metal layers which are connected to a selected metal layer.

Thanks,
Mallikarjun

  • Andrew Beckett

    Are you using Virtuoso Layout Suite XL? Does this need to involve connections to other layers throughout the hierarchy?

    Andrew

  • Mallikarjun032
    in reply to Andrew Beckett

    Hi Andrew,

    The layout I am working on, has only one hierarchy and it has only ("M1" "drawing") layers in it.
    Yeah, I am using Virtuoso Layout Suite XL, but I have to get this done through a SKILL code.

    Thanks,
    Mallikarjun

  • Andrew Beckett
    in reply to Mallikarjun032

    The reason I was asking was because then the shapes have connectivity, and so you can then see if they are on the same net. The dbGetOverlaps could work, but that would only find overlapping shapes - you could then look at the ~>net attribute on each shape to see if they are on the same net as the starting point.

    Or you could use the "mark net" functionality (leMarkNet is the non-interactive function to do this) and then use leSaveMarkNet to save the shapes to a temporary cellView (which was opened in "w" mode initially to ensure it's blank) and then inspect the shapes you end up with the temporary cellView to find out the layers used.

    Andrew.

  • Mallikarjun032
    in reply to Andrew Beckett

    Hi Andrew, 

    Thanks for your suggestions.

    I took the help of leMarkNet() and leSaveMarkNet() functions to get the list of all connected metal layers. I couldn't get much help from the '~>net' attribute for metal layers, because if the net name is 'nil', then the '~>net' attribute will be empty.

    Thanks,
    Mallikarjun

  • Andrew Beckett
    in reply to Mallikarjun032

    Rather surprising that the net would be nil if you're using VLS XL, but anyway, you have a solution...

    Note, I wasn't talking about using ~>net with the results of leSaveMarkNet because that wouldn't have connectivity - I was talking about using it on the original shapes - but either way, you have a way forward.

    Andrew.

  • Mallikarjun032
    in reply to Andrew Beckett

    Hi Andrew,

    I am using VLS XL, and I used the '~>net' attribute on the original layout. Also, the original layout does not have net names assigned to the ("M1" "drawing") metal layers; this may be the reason why the '~>net' attribute is 'nil'.

    Thanks,
    Mallikarjun

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