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Compute a CDF param from two existing parameters

unSkilled

Virtuoso IC6.1.8-64b.500.23

Hi all,

I would like create a user-level CDF that displays the total width of a transistor as the product of a finger width (Wfg) and total multiplier (totalM). Strangely, the total W is not available as parameter. I tried the following:

/****************************************************/
 LIBRARY = "myLib"
 CELL    = "mynmos"
/****************************************************/

let( ( libId cellId cdfId )
    unless( cellId = ddGetObj( LIBRARY CELL )
        error( "Could not get cell %s." CELL )
    )
    when( cdfId = cdfGetUserCellCDF( cellId )
        cdfDeleteCDF( cdfId )
    )
    cdfId  = cdfCreateUserCellCDF( cellId )

    
    ;;; Parameters

    cdfCreateParam( cdfId
        ?name           "totalW"
        ?prompt         "wtot"
        ?defValue       "1"
        ?type           "string"
        ?display        "t"
        ?editable       "nil"
        ?callback       "Wfg*totalM"
        ?parseAsNumber  "yes"
        ?parseAsCEL     "yes"
    )

    ;;; Properties
    cdfId->formInitProc            = "tsmcCdfFormInitCB"
    cdfId->doneProc                = ""
    cdfId->buttonFieldWidth        = 340
    cdfId->fieldHeight             = 35
    cdfId->fieldWidth              = 580
    cdfId->promptWidth             = 300
       cdfId->paramLabelSet           = "Wfg totalW l -m_ov_nf"
    cdfId->opPointLabelSet         = "(gm/id) region vgs vth vds vdsat id"
    cdfId->modelLabelSet           = "vtho toxe cj  "
    cdfId->paramEvaluate           = "nil nil nil t nil"
    cdfSaveCDF( cdfId )
)

--

What happens is that the totalW displayed is the default value, so it doesn't get calculated. I've tried multiple different syntaxes for the product of Wfg and totalM but nothing seems to work. Any hints are highly appreciated.

Regards,

  • Hi,

    You make the callback definition for the wrong parameter - totalW. In fact totalW is the the parameter you actually want to get recomputed  so you need to define the callback(s) for the parameters that totalW depends from - Wfg and totalM. Other than that you need to refer to the values of the CDF parameters in terms of the cdfgData data structure. So to refer to totalW you need to say cdfgData~>totalW~>value.

    regards

    Max

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