Hi Alan,
Help; I'm trying to figure out if these errors are hardware or software. And of course, this is our first ppc/uboot system, so I'm still stepping through a lot of learning as I go.
I'm supposed to have a memory region from 0 to 7fff_ffff assigned to our 128MB memory. However, I run into several issues when trying to run mtest. I end up with an large sections mis-behaving. I don't see any conflicts in the BRx registers, and I believe my OR1 is set up properly, so I'm not sure how to proceed.
First thing would be to start with an oscilloscope.
I'm going to have to do this in a week or two.
Is your memory in a module, or is it directly soldered? Is the memory SDRAM, DDR, DDR2, etc.?
Regardless of the memory type, use a scope to look at the waveforms, relative timing of clock and data, and compare the measurements to the data sheet.
The memory controllers have lots of options with regards to drive strength, and timing, so those need to be customized to a specific board. Chips such as DDR also have internal registers for configuring drive strength.
For example, on the MPC8349EA-MDS board, they use a DDR DIMM module, and require a termination regulator. On my design, the DDR memory will be on the board, and space was a problem, so we simulated 2.5V DDR without a 1.25V termination regulator. The system works in theory :) But I know I will be scoping things out and messing with the drive strength registers using the BDI2000 to talk to the board before I even attempt to run a memory test, let alone attempt to boot from Flash.
Cheers, Dave