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Syouf's avatar
Syouf
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5 years ago

Using external clock to drive FPGA DE10-Nano

Hello,

I am working on a project in which I need to use the clock of DE2-115 to drive a DE10-Nano FPGA. I connected the clock signal of the DE2 to one of its GPIO pins, and connected that pin to a GPIO pin on the DE10 and used it as my input clock. I believe that I've made a mistake, but I don't know what is it, or how to solve it. When I try to see the signals using the SignalTap analyzer, a 'waiting for clock' message is displayed, as if the clock is not detected.

Any sort of help is much appreciated.

Regards,

17 Replies

  • IDeyn's avatar
    IDeyn
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    5 years ago

    Hi Syouf!

    Maybe you doesn't exploit dedicated clock pins? Do you use PLL on DE10-Nano board?

    It's not a good practice to use external clock through GPIO because of jitter requirements.

    You can attach your project or made a more detailed description of your layout.

    --

    Hope it helps,

    Ivan

    • Syouf's avatar
      Syouf
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      5 years ago

      Hi Ivan,

      I want to use the DE10-nano as an ADC only, and send the digital output to another FPGA (the DE2-115) using the GPIO pins. When I used the internal clock of the DE10, everything was working properly. After that, what I did is that I changed the pin assignment of the clock from the internal clock to an external GPIO pin at which I connected the clock that is coming from the DE2 board. I did no other modifications.

      I hope that this gives you a good image of what I've done. I used no PLLs, and yes I didn't exploit the dedicated clock pins and I don't know how to do that, I am new to FPGAs. All that I've done is that I outputted the clock of the DE2 to one of its GPIO pins and connected it to a GPIO pin on the DE10 and assigned that pin to the clock of the DE10 board with no other modifications.

      Please let me know if you need more details. Your help is much appreciated

      • IDeyn's avatar
        IDeyn
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        5 years ago

        Hi Syouf,

        Well, in that case I agree with JohnT_Intel, please ensure that you're using same IO standard for clock pins

        on both boards.

        You can still attach your schematic or project archive for more prompt assist.

        --

        Hope it helps,

        Ivan

  • JohnT_Altera's avatar
    JohnT_Altera
    Icon for Regular Contributor rankRegular Contributor
    5 years ago

    Hi,


    May I know what is the clock frequency and IO standard use? Are you setting the same IO standard on both the DE2 and DE10 design?


  • JohnT_Altera's avatar
    JohnT_Altera
    Icon for Regular Contributor rankRegular Contributor
    5 years ago

    Hi,


    Thanks for sharing the project file. From the project, I observed that you do not set any IO standard on the pin. Could you try to set the specific IO standard used for each pin?


  • JohnT_Altera's avatar
    JohnT_Altera
    Icon for Regular Contributor rankRegular Contributor
    5 years ago

    Hi,


    May I know if you are able to use Oscilloscope to monitor the clock signal?


    • Syouf's avatar
      Syouf
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      5 years ago

      Hello,

      Yes, I monitored the signal on a scope, and detected the 50MHz clock.

  • JohnT_Altera's avatar
    JohnT_Altera
    Icon for Regular Contributor rankRegular Contributor
    5 years ago

    Hi,


    Could you provide picture on how you connect the Clock and may I know where do you monitor the clock signal?


    • Syouf's avatar
      Syouf
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      5 years ago

      Hello,

      Regarding the connection, I simply connected the AC15 pin from the DE2-115 to the AC24 pin on the DE10-Nano via a jumper, and used another jumper to connect the grounds. Anyway, although not needed, I attached a picture of the connection.

      Regarding the monitoring, I tried to monitor the signal using the signal tap analyzer, but a "waiting for clock" message is displayed ( see the picture attached). When monitoring the signal coming out of the DE2, a 50 MHz signal is there (also attached). But, when trying to monitor the signal seen by the DE10, by assigning the value of the AC24 pin to another GPIO pin on the DE10 and monitoring the output on that pin, I only see noise.

      The scope that I use to monitor the signal is Agilent DS06102A

      Regards,

      • IDeyn's avatar
        IDeyn
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        5 years ago

        Hi Syouf,

        Ok, I see. Please attach project files updated with I/O standards and with attached signal tap file for us to inspect your situation.

        --
        Hope it helps,
        Ivan

  • JohnT_Altera's avatar
    JohnT_Altera
    Icon for Regular Contributor rankRegular Contributor
    5 years ago

    Hi,


    May I know if you monitor the signal on the clock provider board or the receiver board?


  • JohnT_Altera's avatar
    JohnT_Altera
    Icon for Regular Contributor rankRegular Contributor
    5 years ago

    Hi,


    Could you check if your board is using 2.5V VCCIO based on JP6 setting? In order to set it to 2.5V, you should short pin 5 and 6.