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find long nest on layout

mlea

Hi all,

Im about to write a skill that find long nets on  a big layout, that filter from the interface down.

the purpose is to detect long nets that goes around( or  through vias), until they go into an instance. if the total length is over a specified threshold , than the net label should be print out.

i assume the correct way here is to flat the all design ( which is possible - the design is check out), and than select nets that cross the interface and follow them.

the main question is how to account for the via crossing into a new layer , and than continue follow the net on the new layer??

can any one share some experience or ideas?

thx

meny

  • what i did eventually is to first generate a GDS file that include only specific nets that Im interested at ( for example: all nets that goes all the way  to the top level , and have a pin that touch the interface).

    you can do that by using some verification tool such as PVS  ( or calibre). than once i have the GDS, i stream in to virtuoso, flat it , and check net by net ( by overlap) to calculate the length.

  • in reply to mlea

    Are you doing the mark net through skill or interactively.

    If interactively, you might want to try the markNet from the Connectivity->Nets->Mark

            ( you need to setup the connectivity layers. Execute leHiMarkNet() the hit F3 to bring up the options form )

    Once it is highlighted you can save the net to an alternate cellview to review.

    You might be able to do it through skill if you use a hiRegTimer

    I will have to see if I can  find an old script that traced a net through the hierarchy.

    Paul

  • in reply to psill000

    Paul

    I need to do that in skill in order to get the full length. and it require skill.

    I would appreciate if you can find that script... it will be a greate help

  • in reply to mlea

    Meny, Paul,

    Both Mark Net (leMarkNet()) and Save Mark Net to CellView (leSaveMarkNet) can be done without needing the UI in current versions; you no longer need to use the "hi" versions of these functions and mess around with hiRegTimer to automate them.

    Regards,

    Andrew.

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