Problems getting BusBlaster running

This topic contains 7 replies, has 3 voices, and was last updated by  Laurence 1 year, 5 months ago.

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  • #53439

    Nicholas
    Member

    I have the latest version of MIPSfpga, and I am running VIvado 2015.4. While I can load MIPSfpga into the Nexys4_DDR board, I can’t seem to get Lab02_C working. The loading through BusBlaster fails. I have some screen captures that I will attach to this note. They include the results of running loadMIPSfpga.bat, and also the Control Panel showing the USB ports (with no errors). I really could use some advice about what to look at to get past this.

    Thank-you,

    Nick

    Screen-Shot-2016-04-15-at-11.39.50-AM

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    #53443

    Nicholas
    Member

    The system posted the message without allowing me to include the third screenshot (third command window from loadMIPSfpga.bat.
    Nick

    Screen-Shot-2016-04-15-at-11.40.35-AM

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    #53550

    Bruce
    Member

    I am working on this problem. In my case, running the script several times (but first deleting the two windows – openocd and gdb), it downloaded correctly. I am trying to determine cause-effect and make this startup more reliable.

    You can execute openocd commands as pass-thru commands from gdb by typing “monitor” or “mo” (for short) then the command. Useful ones are:

    mo halt
    – sometimes the processor is running, especially when the cpu reset button is pushed and gdb doesn’t halt it before attempting to load a program so the ‘mo halt’ can be used then

    load <program file.elf>

    mo resume – resumes execution from the current PC

    The gdb command for resume, it is ‘continue’ or ‘c’

    gdb also has a halt command which is ‘Ctrl-c’.

    Other openocd commands thru gdb:

    mo reset halt – halts and resets the cpu
    mo reset run – resets the core then starts it running, so it starts executing from 0xbfc00000

    mo reg pc – shows pc register

    — Bruce Ableidinger
    Senior SW Eng
    Imagination Technologies

    #53551

    Nicholas
    Member

    Bruce, can you expand on your comment? I tried to run the loadmipsfpga.bat without opening the two windows, but did not have any luck. Can you post a new bat file that does what you suggest?

    Thank-you,

    Nick

    #53552

    Nicholas
    Member

    Bruce, executing the loadMIPSfpga, and then repeatively running the load command, I got it load the code onto the Nexys4_DDR board. I think I had to send it about 10 times before it worked.

    Nick

    #53581

    Bruce
    Member

    Since the connection is not consistent, the problem could be in clock rates and/or delay parameters.

    One thing you can try is to slow down the TCK rate. This is specified in the line

    adapter_khz 15000

    in the file mips_busblaster.cfg which is in the path

    C:\Program Files\Imagination Technologies\OpenOCD\openocd-0.9.2\scripts\interface

    but it is being overwritten by xilinx_nexys4_mips.cfg located in ..\scripts\target so this is where any changes should go.

    I don’t know the granularity of the setting but you could try 10000, 5000, or even 1000 (which is 1MHz).

    You could also issue openOCD commands after it has started up, in its console window.

    Note that the file openocd.cfg sources the mips_busblaster.cfg then the xilinx_nexys4_mips.cfg.

    Another parameter that is related to downloading is

    mips32 scan_delay 20000

    You could try a larger delay or turn it off ( value > 2000000).

    #53582

    Bruce
    Member

    We have an OpenOCD/Bus Blaster document that lists some of the openOCD commands and the mips32-specific ones. But the doc is larger than allowed for an attachment in this forum. If you send me your email address I can send it through email. Mine is bruce.ableidinger@imgtec.com.

    — Bruce

    #53711

    Laurence
    Admin

    The OpenOCD manual is already in the downloads section of community.imgtec.com:

    community.imgtec.com/downloads/mips-debug-openocd-with-bus-blaster-getting-started-guide/

    Thank you Bruce!!

    Laurence

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