[U-Boot-Users] SDRAM Burst Read/Write Test

Wolfgang Denk wd at denx.de
Tue Jan 13 15:03:21 CET 2004

In message <20040113135842.79885.qmail at web41401.mail.yahoo.com> you wrote:
> I am talking about initally booting U-Boot.  The crash
> comes right after initializing the SDRAM, when it is
> moving U-Boot from the flash into SDRAM.  So I can't
> run Linux.  I have verified that this is a burst

You asked  hot  to  verify  that  burst  mode  accesses  are  working
correctly   -  the  test  with  the  best  ratio  of  efficiency  vs.
reliability is to boot Linux :-)

> read/write problem by inhibiting burst operations in
> the ORx register for the SDRAM.  When I set OR_BI
> (SDRAM Burst Inhibit) U-Boot will move on to detecting
> the flash.  If I allow bursts, I don't get to where
> U-Boot detects the flash, and the last printout I see
> is: New Stack Pointer is: 00f9ef78.

For the N+1st time:

> > As pointed out several hundret times before, this usually has nothing
> > to do with the UPM setup, but is a  consequence  of  missing  or  bad
> > initialization sequence of your SDRAM chips.

Implement the chip init  sequence  as  documented  in  the  RAM  chip

Best regards,

Wolfgang Denk

See us @ Embedded World, Nuremberg, Feb 17 - 19,  Hall 12.0 Booth 440
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd at denx.de
Conceptual integrity in turn dictates that the  design  must  proceed
from  one  mind,  or  from  a  very small number of agreeing resonant
minds.               - Frederick Brooks Jr., "The Mythical Man Month"

More information about the U-Boot mailing list