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FrankOuO's avatar
FrankOuO
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4 years ago

The result of Clock divider's Waveform simulation doesn't work properly with top module

Hello, everyone

I just wrote a very simple clock divider by 2,

and I want to add this module: clock_out.v to my top module named light.v

(from the tutorial: Using_the_SDRAM)

But if I running the Waveform simulation

It doesn't output a correct divided clock but an unknown signal after 2 clock,

I guess is not a very complex program to me but not always getting the right result.

I'm really confused right now.

here is my verilog source code and Waveform simulation in attachments.

3 Replies

  • RichardT_altera's avatar
    RichardT_altera
    Icon for Super Contributor rankSuper Contributor
    4 years ago

    Hi @FrankOuO

    Sorry for the delay in response. Do you need further help regarding to this case? Do you able to solve the issue by yourself?

    I would recommend to write a testbench and simulate it using the Modelsim Intel FPGA Starter Edition instead of waveform simulation.

    You may checkout the webpage below for an example.

    https://www.fpga4student.com/2017/08/verilog-code-for-clock-divider-on-fpga.html

    Best Regards,
    Richard Tan

    p/s: If any answer from the community or Intel support are helpful, please feel free to give Kudos.

  • RichardT_altera's avatar
    RichardT_altera
    Icon for Super Contributor rankSuper Contributor
    4 years ago

    I have yet to receive any response from you to the previous question/reply/answer that I have provided but I believed that I have answered your question.
    With that, I will now transition this thread to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you.

    Best Regards,
    Richard Tan

    p/s: If any answer from the community or Intel support are helpful, please feel free to give Kudos.

  • FrankOuO's avatar
    FrankOuO
    Icon for New Contributor rankNew Contributor
    4 years ago

    Sorry for the late reply.

    I've found out the reason why the output clock went wrongly.

    I didn't assign a specific pin to the output clock so that their was no output signal.

    With pin assignment, the waveform simulation and on-board test goes well.

    Thank you! @RichardTanSY_Altera

    Best Regards,

    Frank Lee