From mboxrd@z Thu Jan 1 00:00:00 1970 From: Murray.Jensen at csiro.au Date: Fri, 09 Sep 2005 18:02:48 +1000 Subject: [U-Boot-Users] MPC8560 DDR controller Message-ID: <22584.1126252968@gerd> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de Hi U-Boot Users, I noticed a patch go through CVS a few days ago which updated the DDR DLL workaround for the tqm8560 and tqm8540 boards and it piqued my interest - mainly because we are having trouble with the DDR memory on our MPC8560 board. I am interested in other people's experiences with the DDR controller on their MPC8560 based boards - either positive or negative. Here is our tail ... It appears that noise internal to the processor is corrupting reads from DDR memory (by causing the DDR DLL to drop out). We have played extensively with the DDR configuration, following instructions in AN2583 (rev 2) and the DDR11 errata, with some success - but I don't think we have ever been able to completely eliminate the problem, only greatly reduce its frequency. The things that seemed to help the most were setting the Reduced Drive Strength extended operating mode in the DDR memory chips themselves, and slowing the bus rate from 166MHz to 150Mhz. i.e. both of these really have nothing to do with the processor's DDR controller, or any errata workarounds, they obviously just combine to reduce noise on the bus. Our processors are marked "PPC8560..." rather than "MPC8560.." and are dated 0412 (week 12 of 2004 I believe ??). We were thinking that maybe these were pre-production chips and it might help things if we replaced them with "younger chips". By the way, I believe our chips are version 2.0.2. The board is currently usable for development, but would be unacceptable for production use - but even in development, if you get a crash, you can't really be sure if there was a real problem or whether the memory read simply failed. Does anyone have any experiences and/or advise they could share with us? Thank you for listening. Cheers! Murray... -- Murray Jensen, CSIRO Manufacturing & Infra. Tech. Phone: +61 3 9662 7763 Locked Bag No. 9, Preston, Vic, 3072, Australia. Fax: +61 3 9662 7853 Internet: Murray.Jensen at csiro.au To the extent permitted by law, CSIRO does not represent, warrant and/or guarantee that the integrity of this communication has been maintained or that the communication is free of errors, virus, interception or interference. The information contained in this e-mail may be confidential or privileged. Any unauthorised use or disclosure is prohibited. If you have received this e-mail in error, please delete it immediately and notify Murray Jensen on +61 3 9662 7763. Thank you.