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iPar error when used in CDF

JS20250120924

hi，

When I inserted a mos, I set the Finger width in the cdf parameter to pPar(“pw”), and the total width was set to iPar(“fw”) * iPar(“fingers”) by the callback trigger, but the w parameter that was displayed next to the mos in the schematic ( total width) in the schematic has become error, after testing, I found that it is due to the Finger width using the pPar function, while setting the parameter to a number or a string will not cause error, may I ask what is the reason for this?

  • It's a bit hard to know without knowing which PDK it was. On the symbol, what is the second label expression? Is there a message in the CIW to get expanded info in the event of an error?

    Andrew

  • in reply to Andrew Beckett

    Hi Andrew

    Sorry for missing the key information, the argument to this error is w(Total Width) and its expression is iPar(“fw”) * iPar(“fingers”).

    The CIW message after change parameter “Finger width” to "pPar("pw")" and cause the symbol label error was shown below

  • in reply to JS20250120924

    You didn't say which PDK it was nor what the second label on the symbol was. Or whether there was an error in the CIW that appears when you redraw the schematic containing an instance showing the *Error* message. I'd expect there to be a warning in the CIW:

    *WARNING* An error has occurred while evaluating a label in window(4).
    *WARNING* To replace the label by a detailed error description, type the following in the CIW:
    *WARNING* artSetDetailedLabelErrorFlag( t )
    *WARNING* To revert to the short description, pass nil instead.
    *WARNING* To append the error to a file, type the following in the CIW:
    *WARNING* artSetLabelErrorFile( <file-name> )
    *WARNING* To turn off recording, pass nil instead.
    *WARNING* This message will not appear again during this session.

    If you call artSetDetailedLabelErrorFlag(t) in the CIW and redraw it should tell you more. Or the second function such as: artSetLabelErrorFile("/tmp/labelErrors.txt") would put the same error message in the named file upon a redraw.

    My guess is that the CDF for the device has callbacks which insist on the fw field being a number rather than an expression (hence the info you are seeing when you try to set the parameters); you should take that up with the provider of the PDK.

    Regards,

    Andrew

  • in reply to Andrew Beckett

    hi Andrew

    The PDK was SMIC40ll。

    the second label on the symbol was “w” （Total Width) of the CDF parameters.

    after I call artSetDetailedLabelErrorFlag(t), the detail error shows as below:

    I do get these warning when I redraw the schematic:

    One more thing, when I set "Finger Width" parameter to pPar("pw"), then set this parameter a large number such as 1. Then 

    a new message was shown in CIW, maybe there is somethin wrong in this callback:

    I shall ask PDK provider for more support, thanks for your help Andrew!

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