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Error in delay calculation

KISHORE085

hi all,

I've got  an error while calculating delay using delay function in virtuoso.

the error is : "(\"plus\" 0 t nil (\"*Error* plus: can't handle (nil + 0.0)\"))"Expression "delay(?wf1 v(\"/X1\" ?result \"tran-tran\"), ?value1 2.5, ?edge1 \"either\", ?nth1 1, ?td1 0.0, ?wf2 v(\"/sum\" ?result \"tran-tran\"), ?value2 2.5, ?edge2 \"either\", ?nth2 1, ?td2 0.0 , ?stop nil, ?multiple nil)" does not evaluate to waveform."

i couldn't figure out what was the error. Please help..

 Virtuoso version: IC6.1.5.72

  • Tom Volden

    SKILL errors which include nil as one of the arguments like "plus: can't handle (nil + 0.0)" often indicate that a triggered event has not happened.  Based on the expression that you have I would try plotting /X1 and /sum and checking to see if they both cross your threshold value of 2.5 V.

  • frankaurora

    The parameters ?td1 and ?td2 don't work in the example below because whatever value they are specified the time at which to start delay measurement is always time 0.

    tplh=delay( v("CLK1") 2.5 3 ?td1 15u "rising" v("OUT1") 2.5 2 "rising")

    Please give me some clue. Thanks.

  • KISHORE085
    Its ok. i got it. while giving the inputs, i have given only 1 bit to all and i got 1 bit output. so i got that error. Anyways thanks for replying..
  • Andrew Beckett

    frankaurora said:

    The parameters ?td1 and ?td2 don't work in the example below because whatever value they are specified the time at which to start delay measurement is always time 0.

    tplh=delay( v("CLK1") 2.5 3 ?td1 15u "rising" v("OUT1") 2.5 2 "rising")

     

    There was a bug where the delay function from the calculator got generated with a mix of positional (e.g. the first three arguments above, plus some others later, and keyword arguments. Unfortunately the implementation requires you to use all positional, or all keyword. I don't know what version of Virtuoso you're using, but in IC615 this was fixed so that the calculator will generate the correct expression using keyword arguments. 

    Also, the documentation now encourages you to use the keyword argument form (and I think you have to if you want ?td1).

    Kind Regards,

    Andrew.

     

  • frankaurora

    Hi Andrew, 

     Thanks a lot! This problem confuses me for a long time.

    It really works with all keyword arguments. 

     Frank 

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