[U-Boot] RAM burst mode problem

[Mikhail Zaturenskiy]

We finally solved our DRAM timing problem so I wanted to follow up on
my question.

On Fri, Sep 4, 2009 at 1:41 AM, Frank Svendsbøe
<frank.svendsboe at gmail.com> wrote:
> Hi Mikhail,
> Burst mode UPM setup is not trivial, and it is quite amount of work to
> go through your table, so
> I'm not surprised nobody has replied.

I know, I'm not too surprised either :)


> I assume you've verified the generated waveforms using a logic
> analyzer/scope, and compared
> them to the DRAMs datasheet (?).

Unfortunately we do not have access to a decent scope nor a logic
analyzer, that would certainly have been helpful.


> If you have access to a Windows
> machine, you could try an
> ancient Motorola tool called UPM860. It might be helpful when
> verifying your UPM program.

Did take a look at that, though it did not appear to be as helpful as I hoped.


> Good luck!
> - Frank

Thanks for your suggestions Frank, They did provide me with some food
for thought.

What the issue ended up being was us incorrectly setting the amx0/amx1
bits of the "Exception" RAM word. After we fixed that we also found a
nice document from Micron on DRAM timings which had slightly more
efficient read/write section values than what we came up with, for
those interested here is the link
http://download.micron.com/pdf/technotes/TN4812.pdf . Now RAM burst
reads/writes are finally working properly :)

Mikhail Zaturenskiy