How to size transistors using SKILL

Krishna,

You appear to be getting confused about what ID does what.

First of all, the result of dbOpenCellViewByType is not a window id. It's a cellView id. Whilst the variable name doesn't matter, calling it windowID is just confusing.

Secondly, you would want to set the w and l on an instance id (i.e. the return value ofdbCreateInst). Setting it on a cellView id makes no sense.

So you probably want:

cellViewID = dbOpenCellViewByType("test_schematic" "skillSchematic" "schematic" "schematic" "w")

masterID = dbOpenCellViewByType("analogLib" "nmos4" "symbol")

instID=dbCreateInst(cellViewID masterID "I0" 1:1 "R0" 1)

instID~>w="10u"

instID~>l=" 130u"

For example.

Regards,

Andrew.

 Thank you very much Andrew! It worked. I was trying to set the height and width using cellViewID and masterID callbacks.

But why does this not change the value in the CDF Parameter list (in the properties) of the instance?

When I use this :

instID~>w="10u"

instID~>l=" 130u"

 It only changes the value of width and length next to the instance but not in the CDF Parameter list??

 But afer I change the values in the CDF Parameter list it updates. I don't understand this behaviour!

The only reason this could happen is if the parameters are not actually called w and l that are displayed in the CDF. If the property names match (and are of the correct type), then the CDF for an instance ALWAYS uses the instance property to override the CDF default.

Sometimes there are "CDF Callbacks" which are used to derive one CDF parameter from another whenever you  modify the value of one parameter. You might have (say) "wf" from which "w" is computed (or something similar). For more information see my Cadence Online Support note The Dangers of CDF Callbacks together with How to call CDF callbacks procedurally from SKILL?

Regards,

Andrew.

Andrew, I think I am close.

The behaviour that I am observing is, the width and the length does not change in the CDF Parameter list after I do this:

instID~>w="10u"

instID~>l=" 130u"

These values are put next to the instance (I read one of your older posts.)

These get changed once I go to the instance properties->"Modify"->"Apply". Then the values are changed in the CDF Parameter list.

But this does not automate the sizing process. So how can I modify the values?

 I tried : cdfID = cdfGetInstCDF(instID), using this callback it does not let me modify the attributes.

This doesn't make any sense (by the way "cdfId = cdfGetInstCDF(instID)" is not a callback, just to correct your terminology). The best thing would probably to contact Cadence Customer Support so that somebody can take a look at precisely what the problem is - I'm sure there is some aspect of the issue here you're not capturing correctly or clearly in order for me to diagnose it. Having one of the support team (of which I'm part of, in Europe) have a look at your actual data would really help here.

Regards,

Andrew.