MC 68360: first start by BDM with empty flash?

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regards

Dejan

Via the BDM, you can read and write processor registers, system registers, memory, and memory-mapped peripherals. The basic idea is to use the BDM to set up the chip selects, clock module, ram module, and any other initialisation you need. You then download a flash programmer stub (as you suggested) to ram, and the flash image to a ram buffer (depending on sizes, the buffer may need to be used many times over). The BDM starts the burner program, which exists to the BDM with a "break" instruction.

There are commercial programs that automate this - we have used P&E Micro's flasher program with their BDM unit. You can also roll your own - try sourceforge.net/projects/bdm/ as a starter. It's also quite possible (and practical) to use gdb scripts.

Sorry to follow up to my own posting, but I just discovered, that even Scott Howards's old BDM supports this by the "FC" command. That's enough to get access to MBAR - just "FC 7" and write to MBAR.

Thanks, David. The problem with the 68360 is, that there are no special registers (chip selects etc.) available until you assign them a base address by writing to MBAR. So the only thing you can access is the memory adressed by CS0 (Flash, in my case). And MBAR is only accessable in CPU-Space, i.e. with a Function Code 7, which, again, by a program, can only be done using the MOVES-instruction after setting DFC and SFC. I just didn't saw a way to force the BDM to use the appropriate function code - maybe, I read the manual with my eyes wide shut.

Thanks.

Andreas

Years ago, I did a project using 2 68360s, one as a slave. Surprised when powering up the prototype- it kept resetting itself. The answer was that while the BDM inhibited the master watchdog, it did nothing about the slave, which timed out merrily and reset everything else. Boohoo. Had to add a buffer, OC of course, and this was before single- gate packages were widely available. I think Motorola missed a trick there.

Paul Burke

I've only used the 68332 (and recently a ColdFire), which has doesn't have this problem. However, I note that in the bdm drivers on sourceforge, the drivers will automatically set the DFC and SFC when you access the MBAR register.

David