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Cannot call pPar for CDF parameter

farhan89

Hello,

I wrote a pcell for layout and Symbol view for nmos. There are only 2 parameters that user can define (W and L). These CDF parameters have simple call backs functions to check that value in non zero. When I place the instance of nmos symbol in another schematic and edit the parameters at pPar("W") and pPar("W") then I get the error that:

*WARNING* cdfiSetParamValueOnInst: Could not get a float from property 'W' on instance 'I2'

CDF: An error occurred when evaluating callback.

Callback: W->callback => CheckLW(cdfgData->W)

Message: *Error* eval: undefined function - pPar


I tried changing the formal parameters of symbol view as:
 (
        (W           string   "75e-6"     ) ;; Channel Width
        (L            string  "20e-6"     ) ;; Channel Length
    )

but still it doesn't accept the input as pPar. Can anyone help me what should I modify in CDF parameters to make pPar work ?

My CDF parameter code
    cdfCreateParam( cdfId
        ?name "W"
        ?prompt "Channel width"
        ?defValue "100e-6"
        ?type "string"
        ?display "t"
        ?parseAsNumber "t"
        ?units "lengthMetric"
        ?callback "CheckLW(cdfgData->W)"
        ?storeDefault "yes"
    ?parseAsCEL "yes"
    )
    cdfCreateParam( cdfId
        ?name "L"
        ?prompt "Channel length"
        ?defValue "20e-6"
        ?type "string"
        ?display "t"
        ?parseAsNumber "t"
        ?units "lengthMetric"
        ?callback "CheckLW(cdfgData->L)"
        ?storeDefault "yes"
    ?parseAsCEL "yes"
    )

Thanks

Farhan

Parents

  • Farhan,

    cdfParseFloatString doesn't understand pPar(). I'm not sure why you think it would? If you'd read my "Dangers of CDF Callbacks" article that I referenced earlier, it probably would have been clear that you can't have a CDF callback which works this way, because CDF callbacks are evaluated when the properties of an instance are edited; even if you used the information about the particular hierarchical path you've pushed into (using aelSetLineage and aelEnvCompile/aelEnvExecute, for example), it would only be valid for that one occurrence - there could be other hierarchical occurrences which inherit different values - and so your callback results would be wrong.

    I still don't see why having a pcell helps - this is just a CDF callback question - and you are trying to do something that CDF callbacks really cannot handle (as described in my article).

    Kind Regards,

    Andrew.

Reply

  • Farhan,

    cdfParseFloatString doesn't understand pPar(). I'm not sure why you think it would? If you'd read my "Dangers of CDF Callbacks" article that I referenced earlier, it probably would have been clear that you can't have a CDF callback which works this way, because CDF callbacks are evaluated when the properties of an instance are edited; even if you used the information about the particular hierarchical path you've pushed into (using aelSetLineage and aelEnvCompile/aelEnvExecute, for example), it would only be valid for that one occurrence - there could be other hierarchical occurrences which inherit different values - and so your callback results would be wrong.

    I still don't see why having a pcell helps - this is just a CDF callback question - and you are trying to do something that CDF callbacks really cannot handle (as described in my article).

    Kind Regards,

    Andrew.

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