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Ultrasim simulator Problem

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I built a simple resistive ladder for voltage divider circut with componenets in analogLib. When I tried to simulate this circuit with Ultrasim simulator, the intermediate nodes failed to show the output waveform excepting ground and supply nodes. I added them in the outputs list,tried save all method but none of them worked. It happened with both SPICE and Spetre netlisting formats. I tried this simple circuit when a complex circuit failed to simulate properly. Hence now I find that the resistor is not identified properly in the Ultrasim simulation. Is there any known solution for this probelm??

Thanks in advance for your suggestions


Originally posted in cdnusers.org by gunturikishore28
Parents

  • I dont see any cut or "node x not found" in the ultrasim.out file. But when I carefully observe the element count it differs before and after optimizations. Before it shows 3 resistors and after only one. There seems to be some misleading optimization by the tool before actual simulation. rcut and rshort are set to 1e-6 in my option form which I think are default values.


    Let me show you how my netlist appears.

    simulator lang=spectre
    global 0 vss! vdd!
    include ......ic5141/tolls/dfII/samples/artist/ahdlLib/quantity.spectre
    include /...../model.scs section=typ_res

    //RNWELL instance R2 = spectre device R2
    R2 (net14 vss!) rnwell l=15u w=3u

    //RNWELL instance R2= spectre device R0
    R0 (net16 net14) rnwell l=15u w=3u

    //RNWELL instance R1= spectre device R1
    R1 (vdd! net16) rnwell l=15u w=3u

    include /.../graphical stimuli

    .probe tran v(*) depth=1

    tran tran stop=1e-6

    Here is how model library looks like. I changed the values of parameters.

    sectiontyp_ res
    rnwell=100
    //some other constants
    include same file section= res
    endsection typ_res

    section res

    subckt rnwell (n2 n1)

    parameters l w lr=l wr=w rsh=rnwell dl=1e-6 dw=-1e-6 vc1=1e-2 vc2=1e-4 tp=temp
    rnw (n2 n1) resistor r= " mathematical expression which evaluates fine with spectre simulator"
    end section res

    previously The model was bsource with spectre which is not identified with ultrasim simulator. I changed the model now to resistor which is identified but not working properly.

    At one point in the big ultrasim.out file the statement are like this which should be leading to wrong dsimulation in my opinion.

    Elemetn count:

    Element Count Before
    Resistor 1 3
    vsource 1 2
    Total 2 5

    I think I am more clear in my problem statement.


    Originally posted in cdnusers.org by gunturikishore28
Reply

  • I dont see any cut or "node x not found" in the ultrasim.out file. But when I carefully observe the element count it differs before and after optimizations. Before it shows 3 resistors and after only one. There seems to be some misleading optimization by the tool before actual simulation. rcut and rshort are set to 1e-6 in my option form which I think are default values.


    Let me show you how my netlist appears.

    simulator lang=spectre
    global 0 vss! vdd!
    include ......ic5141/tolls/dfII/samples/artist/ahdlLib/quantity.spectre
    include /...../model.scs section=typ_res

    //RNWELL instance R2 = spectre device R2
    R2 (net14 vss!) rnwell l=15u w=3u

    //RNWELL instance R2= spectre device R0
    R0 (net16 net14) rnwell l=15u w=3u

    //RNWELL instance R1= spectre device R1
    R1 (vdd! net16) rnwell l=15u w=3u

    include /.../graphical stimuli

    .probe tran v(*) depth=1

    tran tran stop=1e-6

    Here is how model library looks like. I changed the values of parameters.

    sectiontyp_ res
    rnwell=100
    //some other constants
    include same file section= res
    endsection typ_res

    section res

    subckt rnwell (n2 n1)

    parameters l w lr=l wr=w rsh=rnwell dl=1e-6 dw=-1e-6 vc1=1e-2 vc2=1e-4 tp=temp
    rnw (n2 n1) resistor r= " mathematical expression which evaluates fine with spectre simulator"
    end section res

    previously The model was bsource with spectre which is not identified with ultrasim simulator. I changed the model now to resistor which is identified but not working properly.

    At one point in the big ultrasim.out file the statement are like this which should be leading to wrong dsimulation in my opinion.

    Elemetn count:

    Element Count Before
    Resistor 1 3
    vsource 1 2
    Total 2 5

    I think I am more clear in my problem statement.


    Originally posted in cdnusers.org by gunturikishore28
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