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SKILL descend into a component sub-circuit schematic

AleksandrV

Dear all,

I'm currently working on a impedance matching tool that will be run using Cadence SKILL and OCEAN and have stumbled upon a small problem.

I'd like to do the following:

1) Open an existing schematic that has components inside. Each of the components have sub-circuits inside, but they are not parametric cells.

2) Descend into a particular component and change the value of a component which is inside the sub-circuit parameter.

In other words I have a top level schematic A that has a component B. And I want to access component C parameters which is a sub-circuit inside of a component B in the top level schematic A.

I know how to open a schematic, find and change the parameters of an existing component (in this case it is component "Cpad1" in a schematic "ind_lossy" in a library LIB_NAME):

    cvIdTemp = dbOpenCellViewByType(LIB_NAME "ind_lossy" "schematic")
    dbReopen(cvIdTemp "a") ;to remove locked status of the opened cell view
    
    instanceSelection= dbFindAnyInstByName(cvIdTemp "Cpad1")
    
    instanceSelection~>c = 123e-12
    dbSave(cvIdTemp)
    dbClose(cvIdTemp)

I was wondering - how would one descend into a component sub-circuit schematic and change parameters inside using SKILL, save and close both the sub-circuit and the top schematic?

Thanks,

Aleksandr

  • Hi Aleksandr

    Perhaps you are looking for "dbGetAnyInstSwitchMaster"? Please refer to $CDSHOME/doc/skdfref/skdfref.pdf.

    You can actually just use dbOpenCellViewByType repeatedly too. E.g. if you know that the instances are all using "schematic" views, you can just use this:

    subCell=dbOpenCellViewByType(inst~>libName inst~>cellName "schematic" "" "a")

    It is a very simple method and works well most of the time because most people use "schematic" and "layout" as the actual view names. Once you have obtained the subCell ID using either dbGetAnyInstSwitchMaster or dbOpenCellViewByType, you can repeat the process of dbFindAnyInstByName and then modify the parameters using "instID~>param=123".


    Best regards
    Quek

  • Hi Quek,

    Thanks for the reply.

    I'll look up the "dbGetAnyInstSwitchMaster", but if repetitive "dbOpenCellViewByType" works as well, I'd rather use that.

    Thanks,
    Aleksandr

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