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VIVA Evaluation error for calculator expression over corners in ADE Assembler

Senan

Hello,

I am using Cadence Virtuoso version IC6.1.8-64b.500.6

I have designed a frequency output temperature sensor. I have formulated the sensor sensitivity s(f) over corners, which is yet only the temperature, the basic idea is to monitor the sensitivity change with T which helps me to investigate the sensor linearity. 

I used the ADE assembler to enter the sensitivity expression, which simply df/dT, where I used the Cadence calculator to calculate it using the "deriv" function. I have selected "all" from the EvalType.

Until this point there is no problem, I run the simulation and cadence presented me correctly the sensitivity over corners as shown in the picture below:

Then later I wanted to do more calculation over it by sending it to the calculator, for example applying average or whatever function. The data type in the calculator looks like as shown below

And I recived the following error after applying my averag function to the signal as shown below

Thank you for your help in advance

Regards

  • I would suggest first trying calling the output something other than S(f). It looks rather like a SKILL function, and that almost certainly confuses everything - it should map it to something legal, but clearly it isn't. Try calling it S_f or something like that instead.

    I don't know for certain if that will fix it - I don't have something I can quickly try this out on, but hopefully that's it!

    Andrew

  • in reply to Andrew Beckett

    Hello Andrew

    Thanks for replying me,

    I have tried your suggestion, no Cadence is not complaining about the naming issue, but still can not evaluate the signal, even if I would simply try it from the calcultaor without any function he will give me this error

    ERROR (VIVA-3002):expression evaluation failed: Expression evaluates to nil

    ERROR (VIVA-3002):expression evaluation failed: leafValue( S_f "PointID" "All" )

    is there any way to change the data format ? what is leafValue

    Thank you

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