microblaze xmd question..

A hardware module connects to the FPGA's JTAG interface, and to the debug/control signals on the MicroBlaze. No software intervention is required. You can set hardware breakpoints, watchpoints and all that good stuff.

A small software handler (stub) is installed in low memory, and communicates via serial (not JTAG) to the XMD utility on the development machine.

Option (1) is to be preferred in almost every case, except if maybe if you cannot spare the logic required for the OPB_MDM debug core.

Option(1) allows fast data and software downloads, via XMD we can download a linux kernel in under 20 seconds, via serial it can take up to 15 minutes.

There's really no comparison - the HW debug is far superior.

Regards,

John

Hi John, firstly, thank you for the prompt reply.. The issue that got me confused is that even when I select to use option

2 (xmd with sw debug stub) the bsb also instantiate a mdm module in my mhs... why is that ? As I understnaded from your answer it should have used a uart or maybe I'm missing something. Thanks, Mordehay.

It's probably just a "feature" of the XBD (board description) file for your board. Just pretend the SW option isn't there. Default to HW - it's really that simple!

John

Thanks again John, I understand that the xmd stub option is not the prefered option but still I would like to understand it properly. You said that the SW stub does not use the jtag so can you elaboarte more regerding the way the xmd_stub connects/communicates with the external world (e.g. gdb). its just that I didnt see any uart or other serial-comm core on the MHS. Thanks for all your help, Mordehay.

You should read Chapter 15 of the Embedded Systems Tools Reference Manual (est_rm.pdf)

If you choose xmdstub as your debug option, it's still your responsibility to request a UART in your system. Then, in the EDK, you select that uart as the debug peripheral.

John

Thanks for your help John... Best regards, Mordehay.