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Use terminal net name as value for an instance's CDF parameter

dontpanic

Hi all! I am trying to find a way to use the name of the net that is connected to an instance's terminal, as a string value for one of the instance's CDF parameters. 

In particular, I have a verilog-A component "sample2disk(vIN)" which when instantiated in an schematic samples and dumps to a text file the voltage "vIN" at its input port. This cell has a string parameter "signal_name" which I use to generate the output file name. The component works fine, but currently I need to hard-code the "signal_name" parameter for every instance of this component that I use in an schematic. For example, if I have 2 instances of this component connected to the signals "stage1_vout" and "stage2_vout" in my schematic, then I would need to hard-code these names as values for the corresponding "signal_name" parameters. Instead, I would like to use a skill function that returns automatically these signal names so that they don't not remain hardcoded, allowing for a correct operation when reusing this cell multiple times in an schematic or when copying and pasting across schematics.

I would be really grateful if someone could please help me to figure out how to achieve this behavior (if possible at all).

Thanks in advance for any help!

Cheers,

Jorge.

Parents
  • Andrew Beckett

    Hi Jorge,

    This can be done with a custom netlisting procedure. For example, if you have the following VerilogA code:

    // VerilogA for mylib, sample2disk, veriloga

    `include "constants.vams"
    `include "disciplines.vams"

    module sample2disk(vin);
    input vin;
    electrical vin;
    parameter string netname="dummy";
    integer handle;

    analog begin
        @(initial_step) handle=$fopen(netname,"w");
        $fdisplay(handle,$abstime,V(vin));
        @(final_step) $fclose(handle);
    end

    endmodule

    Then you can use this netlist procedure (instructions in the comments as to how to set up the CDF to reference it; because VerilogA normally uses view-specific CDF, you have to use SKILL to change it as there's no UI for it on the Edit CDF form). Then make sure the code is loaded (e.g. from your .cdsinit).

    /* abNetlistSampleToDisk.il

Author     A.D.Beckett
Group      Custom IC (UK), Cadence Design Systems Ltd.
Language   SKILL
Date       Nov 10, 2014 
Modified   
By         

Assuming that the veriloga model has a parameter called netname, and a single pin

Do this to set up the view-specific CDF

lib="mylib"
cell="sample2disk"
view="veriloga"
paramName='netname
almSetParameterList(lib cell remove(paramName almGetParameterList(lib cell ?view view)) ?view view)
almSetNetlistProcedure(lib cell 'abNetlistSampleToDisk ?view view)

***************************************************

SCCS Info: @(#) abNetlistSampleToDisk.il 11/10/14.17:16:24 1.1

*/

procedure(abNetlistSampleToDisk(inst)
    let((signals )
        nlPrintInst(formatter inst)
        signals=nlGetSignalList(inst)
        nlPrintString(nlGetNetlister(inst) " netname=\"" car(signals) "\"")
    )
)

    This will netlist ensure that you end up with a lines in the netlist such as:

    I15 (net9) sample2disk netname="net9"
    I14 (out) sample2disk netname="out"

    Hope that helps!

    Kind Regards,

    Andrew.

Reply
  • Andrew Beckett

    Hi Jorge,

    This can be done with a custom netlisting procedure. For example, if you have the following VerilogA code:

    // VerilogA for mylib, sample2disk, veriloga

    `include "constants.vams"
    `include "disciplines.vams"

    module sample2disk(vin);
    input vin;
    electrical vin;
    parameter string netname="dummy";
    integer handle;

    analog begin
        @(initial_step) handle=$fopen(netname,"w");
        $fdisplay(handle,$abstime,V(vin));
        @(final_step) $fclose(handle);
    end

    endmodule

    Then you can use this netlist procedure (instructions in the comments as to how to set up the CDF to reference it; because VerilogA normally uses view-specific CDF, you have to use SKILL to change it as there's no UI for it on the Edit CDF form). Then make sure the code is loaded (e.g. from your .cdsinit).

    /* abNetlistSampleToDisk.il

Author     A.D.Beckett
Group      Custom IC (UK), Cadence Design Systems Ltd.
Language   SKILL
Date       Nov 10, 2014 
Modified   
By         

Assuming that the veriloga model has a parameter called netname, and a single pin

Do this to set up the view-specific CDF

lib="mylib"
cell="sample2disk"
view="veriloga"
paramName='netname
almSetParameterList(lib cell remove(paramName almGetParameterList(lib cell ?view view)) ?view view)
almSetNetlistProcedure(lib cell 'abNetlistSampleToDisk ?view view)

***************************************************

SCCS Info: @(#) abNetlistSampleToDisk.il 11/10/14.17:16:24 1.1

*/

procedure(abNetlistSampleToDisk(inst)
    let((signals )
        nlPrintInst(formatter inst)
        signals=nlGetSignalList(inst)
        nlPrintString(nlGetNetlister(inst) " netname=\"" car(signals) "\"")
    )
)

    This will netlist ensure that you end up with a lines in the netlist such as:

    I15 (net9) sample2disk netname="net9"
    I14 (out) sample2disk netname="out"

    Hope that helps!

    Kind Regards,

    Andrew.

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