debug application in sdram (microblaze system)


Is it possible to debug an application which is in sdram by use of xmdstub? I have a small bootloader program which programs a final application into sdram (by use of xmodem). Now I want to debug this application, is that possible or should I use the opb mdm device?! If it's possible, I guess I have to build a bootloader with the xmdstub and make a connection. But how to get my application into the sdram? Can I use the "dow" command at the xmd command line or an option inside gdb to download the application into sdram (I'm asking this, because in the normal way the user has to give some input via the serial port, but that's the same port for debugging thus I can't give any input). And how to step through the code when the application is in the sdram?!

TIA, Frank

Reply to
Frank van Eijkelenburg
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Yes, you can do exactly what you have described. When you use the "dow" command from the XMD command prompt (after an mbconnect), XMD will use the available memory interface core to place the .elf at whatever location has been specified in your linker script. Therefore, you want to "dow" the final application, not the bootloader. You are essentially letting MDM/XMD act as your bootloader in this case.

Once the .elf is downloaded, you can then "con" to run or "stp" (step) from the command line and see what instruction is causing the problem you described in your previous post. If the system hangs on one of your first steps then you probably have a problem with your hardware (likely logical or timing issue with your memory interface and/or board). If this is the case, try using the "mwr" and "mrd" commands from XMD to see if you can get data in and out of your memory correctly.

You can also try to "dow" your .elf file, do an object dump (mb-objdump) of the .elf, then use "mrd" on a large block of the instruction memory, and do a comparison between the dumped .elf and what's in the memory. If there are any mismatches then there's likely a problem with the memory interface hardware/timing.

If it's many instructions into the run, and that instruction memory location looks correct, then the software is likely at fault. Use that dumped .elf file to figure out which instruction is causing the problem and debug accordingly.

Hopefully you are able to resolve the problem using this information. If not then please contact our support hotline for more help.

Best regards, Ryan Laity Xil> Hi,

Reply to
Ryan Laity

It looks like there are some troubles with debugging an application in sdram while caching is enabled (both instruction cache and data cache are enabled). If I remove the cache, I am able to debug my application from sdram. Could anyone confirm this (I saw a few postings at the xilinx microblaze forum, but I couldn't find an confirmation from xilinx about this behaviour)?!









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Reply to
Frank van Eijkelenburg


I was not aware that you were using cache with your SDRAM in this system. To debug with cache support, you must use the MDM.

Ryan Laity Xilinx

Frank van Eijkelenburg wrote:

Reply to
Ryan Laity

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