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OT transient operating points in OCEAN

NewScreenName

Hi all,

I am trying to monitor and do some calculations based on transient operating points (for example monitoring the ron of a switch during time) in ocean script.

When I try to import in the script a waveform, like a current by writing:

axlAddOutputs( list("Ia"))

Ia = IT("/i_DUT/switch/d")

axlOutputResult( Ia"Ia")

it all works fine, however if I use instead Ia = OT("/i_DUT/switch","id") I will get an eval error for Ia. Is there any way to do this?

I am saving both IT("/i_DUT/switch/d") and OT("/i_DUT/switch","id") in my ADE assembler output setup.

Also I have seen that it is necessary to explicitly save voltages and currents that I want to use in an ocean script even though I have set outputs->save all for the voltages. Is there a way to get automatically saved all the currents/voltages used in the ocean script without having to manually defined them as a saved output in the outputs setup?

version used:

Thank you

Parents

  • Dear New ScreenName,

    I am not sure if you still need help with this question, and I do not have access to the Cadence environment currently to validate if things have changed, but I believe there is no comma delimiter in the OT() function. Hence, did you try changing your output expression to save the terminal current from:

    Ia = OT("/i_DUT/switch","id")

    to:

    Ia = OT("/i_DUT/switch" "id")

    NewScreenName said:
    Is there a way to get automatically saved all the currents/voltages used in the ocean script without having to manually defined them as a saved output in the outputs setup?

    In the Virtuoso Visualization and Analysis XL SKILL Reference (Product Version ICADVM20.1, March 2023), it states:

    "To plot or evaluate an OT expression, you must add an OT expression or an oppoint expression to the outputs in ADE Assembler or ADE Explorer and run a simulation. This is because the operating points are not saved when you run a DC sweep or transient simulation, unless they are explicitly used in an expression or an oppoint output."

    Hence, my read of the documentation suggests you must manually include the OT expressions to the ADE Assembler outputs. I will let other experts who monitor this Forum comment on my interpretation if it is incorrect.

    Shawn

  • in reply to ShawnLogan

    A few small corrections:

    1. The comma won't cause a problem - it's effectively the same as a space in this context in SKILL
    2. However, you won't get transient operating points unless you've explicitly saved them - which you can do by adding an oppoint output type (i.e. you add an OP Parameter output). They are not saved by default or globally because saving operating points during transient for all nodes would be expensive.
    3. There is support to auto-save signals used in expressions in the output - however, I don't believe that works with OCEAN script measurements (because it's hard to determine which output expressions are used from an OCEAN script which is very flexible). However, in general, saving all output voltages should allow you to use VT() within the OCEAN script (there are some exceptions where APS or Spectre X might optimise the node away without an explicit save). However, using OT() will never auto-save the corresponding operating point as far as I know.

    Andrew

  • in reply to Andrew Beckett

    Dear Andrew.

    Andrew Beckett said:
    The comma won't cause a problem - it's effectively the same as a space in this context in SKILL

    Thank you for correcting my error! Not having access to the tools, I could not verify this as I noted to NewScreenName - so I do appreciate you taking the time to correct my comment!

    Shawn

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