Stats

  • Locked Locked
  • Replies 1
  • Subscribers 143
  • Views 14495
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Is there any recommended way to update instance parameters

harishgurram

Hi,

Is there any way to update Pcell parameters without forcing to execute CDF Callbacks. The CDF Callbacks are taking more time to execute when i am forcing them to execute in a script. and for every parameter we are changing there is an associated callback withit. So we have to execute all the callbacks must ?

I am using like this 

callback=get(cdfGetInstCDF(car(geGetSelSet())  'w)~>callback

evalstring(callback t)

Is this is the right way?

Parents
  • Andrew Beckett

    There are several things that might be going on here. First of all, depending on the PDK, you may find that calling one of the callbacks is sufficient (at the end) if the callback is common to all and ensures consistency of all the parameters. Secondly the slowness might be due to the parameter changes causing re-evaluation of the pcell, including intermediate steps as each parameter is set.

    If you look at the code referenced in this recent post,  you'll see that abInvokeInstCdfCallbacks takes an argument ?order, so you can tell it which callbacks to call. So for example ?order list("w" "nf") would call just those two in that order.

    If you want to try to minimize the re-evaluation of the pcell, then I would do something like this:

     baseCDF=cdfGetBaseCellCDF(instId~>master~>cell)
     cdf=abCreateEffectiveCDFLookalike(baseCDF t)

    Then make your changes to cdf - so cdf~>w~>value="2u" or whatever your code needs to do to update it. For example:

     cdf~>w~>value=sprintf(nil "%g" w)
     cdf~>wf~>value=sprintf(nil "%g" w*nfingr)
     cdf~>l~>value=l
     cdf~>fingers~>value=nfing

    Then:

     abInvokeObjCdfCallbacks(cdf ?order '("w")) ; or whatever order you need

    And finally apply these to the instance:

    pcellParams=abConvertCdfToPcellParams(cdf)
    dbReplacePropList(instId pcellParams)

    I haven't checked recently (and this probably depends on the version you're using), but I think dbReplacePropList avoids multiple pcell evaluation.

    Note I haven't exactly used the above before - I've used similar within a hierarchical pcell though.

    Regards,

    Andrew.

Reply
  • Andrew Beckett

    There are several things that might be going on here. First of all, depending on the PDK, you may find that calling one of the callbacks is sufficient (at the end) if the callback is common to all and ensures consistency of all the parameters. Secondly the slowness might be due to the parameter changes causing re-evaluation of the pcell, including intermediate steps as each parameter is set.

    If you look at the code referenced in this recent post,  you'll see that abInvokeInstCdfCallbacks takes an argument ?order, so you can tell it which callbacks to call. So for example ?order list("w" "nf") would call just those two in that order.

    If you want to try to minimize the re-evaluation of the pcell, then I would do something like this:

     baseCDF=cdfGetBaseCellCDF(instId~>master~>cell)
     cdf=abCreateEffectiveCDFLookalike(baseCDF t)

    Then make your changes to cdf - so cdf~>w~>value="2u" or whatever your code needs to do to update it. For example:

     cdf~>w~>value=sprintf(nil "%g" w)
     cdf~>wf~>value=sprintf(nil "%g" w*nfingr)
     cdf~>l~>value=l
     cdf~>fingers~>value=nfing

    Then:

     abInvokeObjCdfCallbacks(cdf ?order '("w")) ; or whatever order you need

    And finally apply these to the instance:

    pcellParams=abConvertCdfToPcellParams(cdf)
    dbReplacePropList(instId pcellParams)

    I haven't checked recently (and this probably depends on the version you're using), but I think dbReplacePropList avoids multiple pcell evaluation.

    Note I haven't exactly used the above before - I've used similar within a hierarchical pcell though.

    Regards,

    Andrew.

Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.