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 How to retrieve via spacing of a 2x2 customVia in Virtuoso? 

Last post Tue, Jan 15 2013 2:02 PM by chianga. 2 replies.
Started by chianga 11 Jan 2013 10:53 AM. Topic has 2 replies and 670 views
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  • Fri, Jan 11 2013 10:53 AM

    • chianga
    • Not Ranked
    • Joined on Thu, Dec 13 2012
    • Posts 8
    • Points 230
    How to retrieve via spacing of a 2x2 customVia in Virtuoso? Reply

    Hi, 

    I am trying to write a SKILL routine that increase and descrease number of vias with bindkeys.  I got the routine to work with stdVia but I am running into some problems with customVias.  In stdVia, you can retrieve cutspacing by using the following command:

    stdVia=car(geGetSelSet()) 

    stdVia->viaHeader->overrideParams

    which outputs  ("cutSpacing" (0.07 0.07)) along with other via information

    However, when I use the same command on a 2x2 customVia, there is no cutSpacing information.  I noticed this only happens on a 2x2 via, when a via is 3x3 or bigger the cutSpacing information does appear under overrideParams.

     I am wondering if anyone knows why this is the case and if there are other ways I can retrieve the spacing information.

     

    Thanks,

    Andy

     

     PS I am using IC6.1.5-64b.500.12

     

    • Post Points: 20
  • Mon, Jan 14 2013 4:56 AM

    Re: How to retrieve via spacing of a 2x2 customVia in Virtuoso? Reply

    Andy,

    With a custom via, the exact parameter is dependent upon the implementation of the custom via. In the one I tried, the parameters are called yCutSpacing and xCutSpacing - and are only set in overrideParams if they've explicitly been altered (i.e. increasing the rows and columns doesn't alter them - I don't really see why it would know; that intelligence would normally be built into the pcell, I'd have thought).

    So you might be able to work it out from other technology constraints - but it is likely to be very dependent upon the implementation of the custom via.

    Regards,

    Andrew.

    • Post Points: 20
  • Tue, Jan 15 2013 2:02 PM

    • chianga
    • Not Ranked
    • Joined on Thu, Dec 13 2012
    • Posts 8
    • Points 230
    Re: How to retrieve via spacing of a 2x2 customVia in Virtuoso? Reply

     

    Hi Andrew,

    Thanks again for your explanations.  As you have mentioned, the customVia pcell has a lot of intelligence built in already, for example, the justification is already built in whereas std via the justification is done with originOffset so I didn't need to do much to get my code working besides viaSpacing, which I managed to pull off the tech file.

    If I want to learn more about customVia, can you point me to the documentation on how to impletment it?  I tried to search Cadence documentation with "customVia" without much of the luck.  I have also went over the tech file and again all the implementation is pretty standard like viaSpacing, overlap, etc.  I am curious on how thing like justification is implemented on customVia.

    Cheers,

    Andy

     

    • Post Points: 5
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Started by chianga at 11 Jan 2013 10:53 AM. Topic has 2 replies.