[U-Boot-Users] 85xx running in RAM problems

[David Hawkins <dwh@ovro.caltech.edu>]

Hi Robert,

> On my custom 8548 board I'm getting two different results - with a BDI
> [INIT] config, and without. With the BDI [INIT] config, I can get
> farther by setting the DDR2 ram size to be 256MB instead of what I
> have, 1GB. I have no other SDRAM besides DDR2. 

Have you run any sort of memory tests from the BDI prompt?
For example, lets assume your BDI init file setups up
the DDR2 correctly, but there is a short on the board.

If you run some from of memory checks using the BDI
memory read/write commands, you should be able to detect
the short.

Common tests are walking 1's or 0's over the data bus,
and then clearing RAM and writing to one location, and
testing the result can't be read from more than one
location.

I'm not sure whether the BDI has these sorts of functions
built in, but there are people who've use Tcl/Expect to
layer on the BDI to build a test suite.

Unless you can guarantee your RAM is working fine, there's
no point in trying to get code to run.

The other option is writing a very small program you can load
using the BDI - not a stand-along U-Boot program, just
a stand-alone program that takes over from reset.

Hope that helps,
Dave