How to call a function in a pcDefinePcell

procedure(coordinate_O_function(Width Length Corner) let(() scale = 1.0e6 ; Define the layers w = evalstring(Width ) * scale l = evalstring(Length) * scale cor = evalstring(Corner) * scale x = 0 y = 0 a = w/2 - cor b = l/2 c = w/2 d = l/2 - cor p1 = list(x+a y+b) p2 = list(x+c y+d) p3 = list(x+c -(y+d)) p4 = list(x+a -(y+b)) p5 = list(-(x+a) -(y+b)) p6 = list(-(x+c) -(y+d)) p7 = list(-(x+c) y+d) p8 = list(-(x+a) y+b) ) )

Hi Lorin,

when you define a function outside of the pCell body, you need to load it to your environment, usually from the libInit.il file for your given library. If you are doing a PDK-related work it is best to add all external functions in a separate context file.

In case you need a particular function to sit within the pcDefinePCell body, then you can do it by defining a lambda function anywhere within the variable scope:

pcDefinePCell(l_cellInffo ( ... pCellParams...)

    let((pcellVars)

    ...

    putd('myFuncName lambda((funcParams)

        let((funcVars)

            ... function body ...

        );let

     ));myFuncName

     ....

     myFuncName(param1 param2 ...)

     ....

);pcDefinePCell

I would recommend using the libInit.il approach rather than using putd() within the pcDefinePCell body.

By the way LorinLiu, I would suggest you use cdfParseFloatString() rather than evalstring() in your code to convert to numbers, because you don't want to have the fun of somebody entering "(exit)" as the value of Width...

Andrew

Thank you Andrew for the response and advice. I will try libInit.il approach later and replace evalstring() with cdfParseFloatString() .

But I still want to know what happened to this procedure. I have loaded this function to my environment. When I run DRC, it still reports "undefined function". But I can execute this function alone. Why? body of pcDefinePcell

Because for DRC you are (presumably, you didn't say which tool you're using) doing a stream out (GDS) of the layout and that's done as an external process. Any code you load in the CIW won't be seen.

This is why the suggestion is to put the code in (or load it from) the libInit.il in the library containing the PCell. If you do this, it will be loaded during stream out and the function would then be defined.

Andrew

The DRC tool I use is Calibre. So Calibre won't see the function that I load to the CIW? CIW belongs to Cadence. I see. I will take your advice, Andrew. Thanks a lot. I am a beginner to skill. Thanks again!

Regards,

Lorin

Hi Lorin,

Calibre itself is not reading SKILL, but the first step it runs is to export a stream (GDS) file (essentially the same as using File→Export→Stream) and that's a background process. It's still a Cadence executable, but because it's not in the same process as Virtuoso it doesn't see functions that are in Virtuoso's memory (i.e. what you loaded in the CIW).

Andrew