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JonathanCarlson's avatar
JonathanCarlson
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1 year ago

JTAG UART connection fails after running load in gdb

I'm using Quartus 23.4 (I can't upgrade to a later version) and wanted to run GDB.

I followed the NIOS V processor example and was able to get the Ashling GDB Server and GDB running.

I'm running gdb-server as:

ash-riscv-gdb-server --device 0343B0DD --auto-detect true --probe-type usb-blaster-2 --core-number 0 --jtag-frequency auto-adjust --gdb-port 54321

I'm running gdb as:

/opt/intelFPGA_pro/23.4/riscfree/toolchain/riscv32-unknown-elf/bin/riscv32-unknown-elf-gdb /path/to/exec.elf

Running

(gdb) target remote:54321

I see the GDB server respond with

Got a debugger connection from 127.0.0.1 on port 54321.

If then run

(gdb) continue

I can connect via a JTAG UART interface and communicate to my device.

If I hit Ctrl-C in gdb, I can no longer communicate with the device. But if I run:

(gdb) continue

I can then communicate with the device again via JTAG UART.

However, I want to set a breakpoint which requires loading the exec.elf in gdb.

If I run

(gdb) load

The program successfully loads and I can set a breakpoint.

However, if I run:

(gdb) continue

I can no longer communicate with the device over a JTAG UART connection.

If I only run `(gdb) load` and don't set any breakpoints, I still cannot communicate over JTAG UART.

The JTAG UART communication only fails after running (gdb) load.

Please let me know if you need any other information to help fix the issue. Thanks for the help!

Nios Cpu

14 Replies

  • tehjingy_Altera's avatar
    tehjingy_Altera
    Icon for Regular Contributor rankRegular Contributor
    1 year ago

    Hi


    Is there an error message when you lose the communication after the "load" command?

    If you are using the GUI are you having any issue when debugging the application?


    Regards

    Jingyang, Teh


    • JonathanCarlson's avatar
      JonathanCarlson
      Icon for New Contributor rankNew Contributor
      1 year ago

      Hi,

      There is no error message on either the gdb client or server. The GDB server is still running but the JTAG UART connection is no longer working. I am not using the GUI but am instead using ash-riscv-gdb-server and riscv32-unknown-elf-gdb as described above.

  • tehjingy_Altera's avatar
    tehjingy_Altera
    Icon for Regular Contributor rankRegular Contributor
    1 year ago

    Hey


    Could you try using the JUART connection that is added from the IP Catalog instead? It is free to use from in the Platform Designer.


    Regards

    Jingyang, Teh


  • tehjingy_Altera's avatar
    tehjingy_Altera
    Icon for Regular Contributor rankRegular Contributor
    1 year ago

    Hi


    Do you have an update on this case?

    Have you tried adding the JUART IP from the IP Catalogue instead of the one in GitHub?


    Regards

    Jingyang, Teh


    • JonathanCarlson's avatar
      JonathanCarlson
      Icon for New Contributor rankNew Contributor
      1 year ago

      Hi,

      I am using the JUART IP from the IP Catalog in Project Designer. The GitHub link I provided: https://github.com/thotypous/alterajtaguart/ is just a way to talk to that JTAG UART connection from the host computer.

      Do you know if it's possible to have multiple JTAG UART interfaces on the same FPGA?

      Is it possible this is required if I want to have both the gdb and the JTAG UART console open at the same time?

  • tehjingy_Altera's avatar
    tehjingy_Altera
    Icon for Regular Contributor rankRegular Contributor
    1 year ago

    Hi


    Apologize for the late reply, as I was OOO.


    While using the JTAG UART, you could not access the console from the JTAG.

    Because it is only one JTAG connection, either it is used to output a console or being used as debug.

    Adding additional JTAG UART would not help this situation.


    Regards

    Jingyang, Teh


    • JonathanCarlson's avatar
      JonathanCarlson
      Icon for New Contributor rankNew Contributor
      1 year ago

      Hi,

      No worries about the OOO.

      Are there other available channels (other than JTAG) which a console interface could connect to?

      Is there a recommended way to have a console connection and GDB (over JTAG) running at the same time?

  • tehjingy_Altera's avatar
    tehjingy_Altera
    Icon for Regular Contributor rankRegular Contributor
    1 year ago

    Hi


    Sorry to say that it is not possible to use both the GDB and uart at the same time.

    It is a limitation right now.



    • JonathanCarlson's avatar
      JonathanCarlson
      Icon for New Contributor rankNew Contributor
      1 year ago

      Hi,

      Well, thanks for the confirmation.

      Are there other available channels (other than JTAG) which a console interface could connect to?

      • JonathanCarlson's avatar
        JonathanCarlson
        Icon for New Contributor rankNew Contributor
        1 year ago

        To clarify, I meant: Are there other available channels (other than JTAG UART) which a console interface could connect to?

  • tehjingy_Altera's avatar
    tehjingy_Altera
    Icon for Regular Contributor rankRegular Contributor
    1 year ago

    Hi

    You could add in the UART IP and select the UART IP in the BSP generation when selecting the source of printout.

    Regards

    Jingyang, Teh

  • tehjingy_Altera's avatar
    tehjingy_Altera
    Icon for Regular Contributor rankRegular Contributor
    1 year ago

    Hi


    Are you able to pipe the debug logs to the UART instead of the JTAG UART?


    Regards

    Jingyang, Teh


  • tehjingy_Altera's avatar
    tehjingy_Altera
    Icon for Regular Contributor rankRegular Contributor
    1 year ago

    Hi


    As we do not receive any response from you on the previous question/reply/answer that we have provided. Please login to ‘https://supporttickets.intel.com/s/?language=en_US’, view details of the desire request, and post a feed/response within the next 15 days to allow me to continue to support you. After 15 days, this thread will be transitioned to community support. The community users will be able to help you on your follow-up questions.



    Regards

    Jingyang, Teh