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 Disappearing geometry 

Last post Fri, Mar 5 2010 5:11 PM by Dean1138. 2 replies.
Started by Dean1138 04 Mar 2010 05:34 PM. Topic has 2 replies and 1070 views
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  • Thu, Mar 4 2010 5:34 PM

    • Dean1138
    • Not Ranked
    • Joined on Thu, Jul 17 2008
    • Bevery, MA
    • Posts 3
    • Points 30
    Disappearing geometry Reply

    I have a pCell where contacts are repeated as the width increases -

    pitch = 12 .0

    repeats = (wu + 4.0)/12.0

     This works as expected for all widths EXCEPT the default, minimum, width in the CDF which is 8.0.  When "wu" is 8.0, the contact disappears.  If I make the CDF default 7.0 then the contact does not disappear when "wu" is 8.0 but then the instance has to be touched by a callback which then enforces the minimum "wu" value of 8.0

    Is there a way to avoid having to call the callback for every instance?

    Is there a way to automatically call the callback upon instantiation?

    • Post Points: 20
  • Fri, Mar 5 2010 2:17 PM

    Re: Disappearing geometry Answer Reply

    My wild guess is that you have the CDF default for "wu" different than the pcell default. When you define the pcell (with pcDefinePCell), what is the default value for "wu"? And what is the default value in the CDF (you already said it is 8.0).

    If they are different, then what could happen is that the default value does not get stored on the instance when placed, and so it actually picks up the pcell default, not the CDF default, and hence it misbehaves.

    It's either this or some kind of floating point rounding error. Since you gave so little of the code, I can't really tell.

    Regards,

    Andrew.

    • Post Points: 20
  • Fri, Mar 5 2010 5:11 PM

    • Dean1138
    • Not Ranked
    • Joined on Thu, Jul 17 2008
    • Bevery, MA
    • Posts 3
    • Points 30
    Re: Disappearing geometry Reply

    The pcell parameter default was indeed, another number.  When it was changed to the correct value, the problem went away.

    Thanks,

    Dean

    • Post Points: 5
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Started by Dean1138 at 04 Mar 2010 05:34 PM. Topic has 2 replies.