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 Simulation using SKILL 

Last post Sun, May 24 2009 2:24 AM by first. 11 replies.
Started by deepshah 23 Apr 2009 04:55 PM. Topic has 11 replies and 4353 views
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  • Thu, Apr 23 2009 4:55 PM

    • deepshah
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    • ozone park, NY
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    Simulation using SKILL Reply

     hi,

    I am simulating a circuit block with SKILL

    I wrote Desvar.il, mystimuli.scs, Simsetup.il but i do not know how to proceed with main simulation body can anybody help me?

    i want power data to be displayed 

    Thanks

     

    • Post Points: 20
  • Thu, Apr 23 2009 6:19 PM

    • vlau2
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    Re: Simulation using SKILL Reply

    Are you using ocean?

    Writing SKILL code to simulatre a circuit can be done using an ocean script.

    And in Analog Artist, it can generate an ocean script for you to run the simulation. 

     

    • Post Points: 20
  • Thu, Apr 23 2009 6:42 PM

    • deepshah
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    Re: Simulation using SKILL Reply

     yes i am using ocean script but still you have to give stimuli and design variables as an input.

    my circuit block is with 32 input i do not want to write all of them again and again in to the stimuli i think it can be done by just changing the script, i need different simulation results at different input something like 3-4 iteration you can have at a time.

    Thanks 

    • Post Points: 20
  • Thu, Apr 23 2009 9:06 PM

    • skillUser
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    Re: Simulation using SKILL Reply

    I think you might need to supply a bit more detail, for example what do the files Desvar.il, mystimuli.scs, Simsetup.il contain?

    You can mix core SKILL code with OCEAN code, for example using for loops and foreach or while statements.  If your design is parameterized with appropriate design variables, you can change these with desVar() statements, effectively creating your own sweeps.

    Regards,

    Lawrence.

    • Post Points: 20
  • Fri, Apr 24 2009 4:09 PM

    • deepshah
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    Re: Simulation using SKILL Reply

     Lawrence,

    Desvars.il:

    desVar( "Vdd" 1.0 )
    desVar( "Gnd" 0.0 )
    desVar( "Twwid" SimSetup->Twwid )
    desVar( "Twper" SimSetup->Twper )
    desVar( "A1" A1) desVar( "A2" A2)...... desVar( "A16" A16)

    mystimuli.scs:

    simulator lang=spectre
    vA1 (A1 0) vsouce type=pulse val0=0 val1=1.0 width=2n period=4n.....vA16 (A16 0) vsouce type=pulse val0=0 val1=...

    _vVdd (Vdd! 0) vsouce type=dc dc=1.0
    _vGnd (Gnd! 0) vsouce type=dc dc=0.0


    SimSetup.il:

    procedure(LogTestSetup()
     prog((SimSetup)

     SimSetup = lost(nil)

     SimSetup->LibName = "EXP"
     SimSetup->ViewName = "schematic"
     SimSetup->CellNameList = '("mul")
     SimSetup->StimFileList = '("mystimuli.scs")
     SimSetup->VariablesFile = "/home/../simexp/mydesvars.il"
     SimSetup->StimFileDir "/home/.../simexp/stimuli/"

     SimSetup->SpectreSimDir = "/home/.../simexp/simulation/"
     SimSetup->ResultsDir = "/home/.../simexp/results/"
     
     SimSetup->LogFileName = "log.txt"
     SimSetup->OutputFileName = "simexper_logblock.txt"
     SimSetup->LogFileName = strcat(SimSetup->ResultsFileDir SimSetup->LogFileName)
     SimSetup->OutputFileName = strcat(SimSetup->ResultsFileDir SimSetup->OutputFileName)

     SimSetup->PlotWaves = 0
     SimSetup->Renetlist = 1
     SimSetup->ParametricAnalysis = 0
     SimSetup->SimStop = 50n

     SimSetup->A1 = '(0 1 0 1 ....)
     
     SimSetup->Twwid = 2n
     SimSetup->Twper = 4n
     
     return(SimSetup)
    )
    )
     

    I hope i am going in right direction from here i dont know how to create main simulation body the one with iteration and how to call above mentioned files in main body.

    Thanks


    Deep

    • Post Points: 20
  • Fri, Apr 24 2009 8:27 PM

    • skillUser
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    Re: Simulation using SKILL Reply

    Hi Deep,

    Aside from the typos ("lost" in SimSetup.il and, "vsouce" in mystimuli.scs) it looks as though you have some pieces of the puzzle.

    You just need the core of the OCEAN script now, something like:

    ;; load the intialization code and call it
    load("SimSetup.il")
    SimSetup = LogTestSetup()

    ;; setup a simulation session using OCEAN commands
    simulator( 'spectre )
    design( SimSetup->LibName SimSetup->CellName SimSetup->ViewName)
    resultsDir( SimSetup->ResultsDir )

    load( SimSetup->VariablesFile )

    analysis('tran ?stop SimSetup->SimStop )
    run()

     

    The main problem I see is that the design does not appear to be parameterized with Twwid, Twper, A1, A2 etc. I would expect to see a "parameters" statement in the spectre netlist which declares them, and later on actually see them being used in place of fixed values, e.g.
     width=Twwid period=Twper

    You may also want to perform your own sort of sweep or parametric analysis, e.g. use a for() or a foreach() looping construct to iterate over different values of one or more parameters.

    I hope that the above helps.

    Regards,

    Lawrence.

    • Post Points: 20
  • Mon, Apr 27 2009 6:45 PM

    • deepshah
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    Re: Simulation using SKILL Reply

     hi,

    Thanks Lawrence and vlau2 for your time and suggestions i did it partially with ocean script, and i generated script from ADE, modify it according to my requirements still i do not know how to simulate it together.

    I have different frequencies so spectre should use different one every time and should give me output at same time at the end.For this any thing available in ocean script?

    What should i add in below script so it will simulate for different frequencies at same time

     procedure(MULSIM()

    simulator( 'spectre )
    design(     "/home/spring08/dshah03/cadence/simulation/mul/spectre/schematic/netlist/netlist")
    resultsDir( "/home/spring08/dshah03/cadence/simulation/mul/spectre/schematic" )
    modelFile(
        '("/home/spring08/dshah03/32nm_NMOS_bulk36360.pm" "")
        '("/home/spring08/dshah03/32nm_PMOS_bulk48193.pm" "")
    )
    stimulusFile( ?xlate nil
        "/home/spring08/dshah03/cadence/simulation/mul/spectre/schematic/netlist/stimuli.scs")
    analysis('tran ?stop "12n"  ?errpreset "moderate"  )
    SaveOption( 'pwr "all")
    run()
    selectResult('tran)
    plot(getData("/O"))
    plot(getData("/A"))
    )

    • Post Points: 20
  • Tue, Apr 28 2009 2:34 AM

    Re: Simulation using SKILL Reply

    Different frequencies of what? Please think carefully about how you ask a question - is it likely we're able to figure out what you're actually trying to do from the last post you made?

    Also, I'm intrigued as to your earlier function LogTestSetup() - it suggests you borrowed some SKILL code from somewhere else, because it's just setting up a disembodied property list and this is not a structure that is used by any of the Cadence simulation environment, so presumably it must be used as part of some framework written by someone else?

    I suggest you read the OCEAN Reference Manual and the SKILL Language User Guide (both in the Cadence installation, in cdsdoc or cdnshelp (depending on the version you're using), or in <ICinstDir>/doc/oceanref/oceanref.pdf and <ICinstDir>/doc/sklanguser/sklanguser.pdf if you want to reference the PDFs directly).

    Regards,

    Andrew.

    • Post Points: 20
  • Tue, Apr 28 2009 11:31 AM

    • deepshah
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    Re: Simulation using SKILL Reply

    I am simulating 16 X 16 multiplier and this block has a clock. I want to simulate this on 1MHz,50MHz, 100MHz, 500MHz, 1GHz. I can simulate each frequency differently but i want to simulate design with these different frequencies in one script(one time you need to run it).

    Actually i assembled the code from different codes.

    Thanks,

    Deep 

    • Post Points: 20
  • Tue, Apr 28 2009 1:11 PM

    Re: Simulation using SKILL Reply

    You probably need to have a voltage source in the testbench for the clock, and control the frequency using a design variable.

    You could then use the paramAnalysis() OCEAN function to sweep this design variable.

    This is covered in the OCEAN reference manual, and also in the OCEAN training class that is available from Cadence (look under the Support and Training link at the top of the page). You can also use foreach() loops and so on to iterate over values, calling desVar() for each value.

    Since from an earlier post you appear to have your stimulus in an ASCII file rather than a schematic testbench, you'd need to parameterize the sources, and then you can use desVar() (and paramAnalysis) to sweep the parameter names you use in your stimulus file.

    Regards,

    Andrew.

    • Post Points: 20
  • Wed, Apr 29 2009 2:00 PM

    • deepshah
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    • Posts 6
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    Re: Simulation using SKILL Reply

     hi,

    Thanks all finally i am able to simulate with the script.

    Now i am facing another problem and that is when i simulate the design it takes 1ps tran steps so it is very slow and i tried all the option it reads like this..  My clock is 50MHz.My input frequency is slower than clock

    Important parameter values:
    start = 0 s
    outputstart = 0 s
    stop = 100 ns
    step = 1 ns it takes these two automatically (step and maxstep) i gave it step=5 ns and maxstep=10 ns
        maxstep = 1.6ns
        ic = all
    skipdc = no
    reltol = 100e-06
    abstol(V) = 1 uV
    abstol(I) = 1 pA
    temp = 27 C
    tnom = 27 C
    tempeffects = all
    errpreset = conservative
    method = gear2only
    lteratio = 10
    relref = alllocal
    cmin = 0 F
    gmin = 1 pS

     Deep

     

    • Post Points: 20
  • Sun, May 24 2009 2:24 AM

    • first
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    • Joined on Mon, May 18 2009
    • Posts 2
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    Re: Simulation using SKILL Reply

     hi,

    just try to turn off the conservative option!

     regards

    • Post Points: 5
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Started by deepshah at 23 Apr 2009 04:55 PM. Topic has 11 replies.