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calculator delay function

swdesigner
I always used cross(), but I'm trying delay() in IC6 and running into issues :

cross(VT("/PV5")-VT("/xlx5/Pgate") 1 2 "falling" nil nil )

that's for signal 1 - 2nd falling edge when crossing 1V. It givesd me 406 ns which is right.

cross(VT("/xlx5/Ngate") 1 2 "rising" nil nil )

is for signal 2 - 2nd rising edge when crossing 1V. It gives me 412 ns - which is right.

I fill out the form for the delay function and I get :

delay(?wf1 VT("/PV5")-VT("/xlx5/Pgate"), ?value1 1, ?edge1 "falling", ?nth1 2, ?td1 0, ?wf2 VT("/xlx5/Ngate"), ?value2 1, ?edge2 "rising", ?nth2 2, ?td2 0 , ?stop nil, ?multiple nil)

When I try this, CIW shows "expression evaluation failed".

But, delay worked for the delay from 1st falling edge of wf2 (above) to 1st rising edge of wf1 giving 5.5 ns correctly with the same values for start1 and start2.

Any help would be super.
  • Amel
    Hi,
    I always use Delay function (in IC.5) with voltages without any problem with the following expressin s bellow:

    delay(VT("/A") 0.9 1 "falling" VT("/Z") 0.9 1 "rising" 0 0 nil nil    )

    when I eveluate the expression it gives me the delay.

    try it with voltages. I think it also feasable in IC.6

    Amel
  • Andrew Beckett

    Not sure which version you're using, but there were some fixes added in IC6.1.5 to handle the keyword arguments properly on the delay function.

    Other than that, hard to know without seeing the data. Maybe logging a service request would be your best bet.

    Kind Regards,

    Andrew.

  • wgtkan
    I am using Cadence 6.1.5 -64b.72 and I am running into similar problem using the calculator to find a delay past the first edge of the waveform. It only works for the first edge not for the second or fourth edge.

    Thank you.
  • Andrew Beckett

    If you used the calculator from IC615 to build the expression, it should work - provided you've entered the fields properly.

    Can you post the expression, and maybe a picture (save an image from ViVA and then upload it via the Options tab) to show what you're trying to measure?

    That said, IC615 had a major change in quite a few parts of the tools.  The subversion you are using is the Base release, which came out 2 years ago - there have been a lot of fixes and enhancements in the meantime and so I would strongly recommend moving to the latest hotfix of IC615.

    Regards,

    Andrew.

  • wgtkan
    Thank you for your promote response.

    I am trying to measure the propagation delay low to high which is the delay time between the 50% transition of the falling input voltage and the 50% transition of the rising output voltage and I enter in the delay special function:

    My input is A and my output is Z. to measure the low to high delay time I must use the second falling edge of the input and the second rising edge of the output. I enter these values in the delay function. For some reason when I enter ok: This is what I get on the buffer:

     delay(?wf1 VT("/A"), ?value1 0.9, ?edge1 "falling", ?nth1 2, ?td1 0.0, ?wf2 VT("/Z"), ?value2 0.9, ?edge2 "rising", ?nth2 2,  ?td2 0.0 , ?stop nil, ?multiple nil).

    And that is wrong because I chose the second edge for both input and output. Instead I used the marker to find the actual low to high delay. Please see the attached picture. Is the new fix available to remedy this issue? I saved the picture from ViVa but it wont let me upload it. I have sent you the picture via your email.

    Regards,

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