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Diff between "fig" and "figs"

SrBraj

Hi

I have placed a device in a layout view "try1" 

cv = dbOpenCellViewByType("testAqua" "try1" "layout")

I want to get the device pins layer name, I am using the following skill keywords.
#1 cv~>instances~>master~>terminals~>pins~>fig~>layerName
output: ((("DIFF") ("DIFF") (nil) )
)
I also noticed that there is an extra keyword "figs" which can give all the shapes associated with the corresponding pin.
#2 cv~>instances~>master~>terminals~>pins~>figs~>layerName
output: (((("DIFF" "MET1")) (("DIFF" "MET1")) (nil) )
)
I want to know that how the #1 get the value? What are the changes required to get the output value as
((("MET1") ("MET1") (nil) )

  • Andrew Beckett

    The reason for both fig and figs existing is for legacy support (fig is the one there for legacy). In CDB (the database used up to and including IC5141), pins could only have a single figure. In OpenAccess (used in all IC6.1.X/ICADV/ICADVM releases), the pin connectivity model is such that pins can have multiple figures; all figures on a pin are deemed to be "strongly connected" - so connecting to any one of the pin figures is sufficient.

    The ~>fig is maintained for compatibility with older code, but of course it means that any such code would only be seeing one of the strongly connected pin figures. Much of the time there is only a single pin figure, so this is not too problematic (Virtuoso schematics never use strongly connected pins, so it's never an issue there - it's only going to be in layout that you might have an issue, and even then it might be OK depending on what the tool is doing). The fig attribute is picking one of the figures - arbitrarily (it's probably the first, but given that they're not ordered, you should not read anything into any empirically observed behaviour you might see as to which one it is).

    Andrew.

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