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Ho to find top level connectivity for instances using SKILL in Layout

Miguel V

Hi,

I have a set of bondpads and I am trying to write a SKILL function that will display the coordinates and top level connectivity for each bondpad.  For example, I have pads labeled PWR, PWRres, GND and clk at the top level. I want the function to output something like this:  bondpad   (x,y)     PWR

I got the coordinates to display properly but still having troubling pulling the net associated with each bondpad.  I've searched quite a bit on here and other sources but I'm currently stumped.  Any ideas on how to approach this or are there other properties associated with cv~>instances that I am missing?  I've tried using inst~>conns~>net~>name but all I get are the connections at the cell level which end up being "IO" or "sub"

Thanks 

  • The trouble is, I don't think we can guess what your IO cells look like, what pins they have, whether there is connectivity at all (are you using VLS XL?) or on these pins.

    I suggest you contact customer support so that we can look at the data with you and figure out the best strategy. There are so many ways that people create I/Os and instantiate bandpads that any code may or may not work depending on your methodology.

    Regards,

    Andrew.

  • Hi Andrew,

    Yes I am using VLS XL. There is a pin and label attached to each bondpad and at each cell/instance in the hierarchy. My current code gives me the correct PIN names for each instance, but only at the top level. I just wanted to know if there is some way of traversing the hierarchy from the top level cell to the bondpads in the lower level cells. Would flattening all instances work?

  • Flattening is almost certainly overkill and not a good idea - it may destroy the connectivity anyway. It's easy enough to traverse the hierarchy in SKILL (numerous examples on these forums) but I wouldn't guess what the right way to do this without seeing your data or your current code, which is why I suggested going to customer support so that somebody can advise with the correct contextual information to hand.

    Regards,

    Andrew.

  • I figured as much which is why I didn't do it.  I was able to use leSearchHierarchy() to traverse the hierarchy, but the solution for me was to traverse the hierarchy and get all of the instances, then pull out the bondpads and coordinates, then use dbGetTrueOverlaps() to get overlaps of the pins over the bondpads and extract the pin names.  It wasn't until after I got it to work that I discovered the "Pad Opening Info..." option under Tools in my layout window, which does almost EXACTLY what I was trying to do...sigh.

    Miguel

  • Hi Miguel,

    I understand your feeling now. Sorry for that. May be if you had given more description on your requirement some one would have pointed you this. Sometimes we try to build a world with our little knowledge of SKILL and finally get embarrassed with an already available tool. But nothing goes waste I bet you might have sharpened your SKILL scripting when you try to reinvent the wheel.

    -Ramakrishnan

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