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Altera_Forum's avatar
Altera_Forum
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14 years ago

NCO-simulation in modelsim not successful

Hello,

i have a problem with my NCO-block.

I have created an nco-block in quartus 11.1 and want to simulate it with modelsim altera.

I wrote a testbench (without creating errors) and simulated it in modelsim.

The input signals are created in the right way.

The outputs (sin, cos, valid) are constants (0).

It seems that the block does not know what to do.

It would be fine if anyone could help me!

Thanks! :)

6 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    --- Quote Start ---

    It would be fine if anyone could help me!

    --- Quote End ---

    Create a zip file containing your NCO instance and your testbench code. If you know how to create a Modelsim Tcl script, add that too. Post the zip file to this thread, and then we can look at it.

    Cheers,

    Dave
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    Did you create a functional simulation model in the MegaWizard? Did your simulation load this simulation model?

  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    --- Quote Start ---

    attached you can find the zip-file (included: tcl-file).

    --- Quote End ---

    There is no Tcl simulation file in there that you wrote. Only you know what component should be simulated, so you should really write one yourself.

    Here's what I did.

    1) Unzipped the zip file, into eg., c:/temp/klause, which created c:/temp/klause/D8PSK

    2) Started Modelsim-ASE and changed directory to c:/temp/klause and typed

    vlib work

    to create a work folder. Typing 'vmap work' shows that the work folder maps to the default location ./work. If you don't see that, type 'vmap work ./work'

    3) Compile the source

    vcom D8PSK/nco.vho

    vcom D8PSK/MY_TESTBENCH/tb_D8PSK.vhd

    this fails, since your testbench is trying to simulate your project top-level entity, whereas you want to simulate the nco, so I edited the file and changed the code to 'dut : entity work.nco', and then it compiled fine.

    4) Simulate

    vsim -novopt tb_D8PSK

    add wave *

    run 10 us

    It worked fine. What didn't work for you?

    Cheers,

    Dave
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    thank you! now it works! :)

    i did not realized that i have to refer to the nco.vho and not to the top level entity.

    but if i have more blocks than one i have to use the top level entity, isn't it?

    or is there anything else that i have to consider to make the simulation work?
  • Altera_Forum's avatar
    Altera_Forum
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    14 years ago

    --- Quote Start ---

    thank you! now it works! :)

    --- Quote End ---

    Great!

    --- Quote Start ---

    i did not realized that i have to refer to the nco.vho and not to the top level entity.

    --- Quote End ---

    It depends on what you are trying to simulate. Your forum title requested NCO simulation, so that is what I helped you with.

    --- Quote Start ---

    but if i have more blocks than one i have to use the top level entity, isn't it?

    or is there anything else that i have to consider to make the simulation work?

    --- Quote End ---

    If you have a top-level design, then you just need to make sure you compile all the components it uses, and then edit the testbench to instantiate the top-level design (making sure that all the port names match). When you use vsim to simulate the top-level, look at the log messages in the Modelsim window and you will see all of the other components being loaded.

    Cheers,

    Dave