Hi Tom,
I observed some issues on our Siemens CPU boards with am3352 configuring 2Gbit 
DDR3 from Samsung (K4B2G1646Q). Before we used a 1 Gbit DDR3 memory from 
Samsung as well and other manufacturers that worked fine. With 2 Gbit I 
noticed, after some trial and error (and adapting tRFC parameters to the new 
size), that for Samsung I need to wait some extra time (around 200us) after 
calling the configuration function config_ddr(...) before proceeding.

This is necessary when a soft reset happens but not when the device makes a 
power cycle. And this is only an issue for Samsung K4B2G1646Q. We also have 
some hardware with 2Gbit DDR3 from ISSI that don't see this issue. From a 
datasheet perspective there shouldn't be any significant differences but of 
course I cannot vouch for it. 

So my question is now if you know somebody that observed similar issues with 
K4B2G1646Q DDR3 and if there is a better solution than adding a udelay(200) 
after the configuration call? I don't understand the issue completely, so I 
guess there might be a better solution out there.

Kind regards
 Sam

Siemens Schweiz AG, Building Technologies Division, International Headquarters
Infrastructure & Cities Sector
Building Technologies Division
Control Products & Systems
IC BT CPS R&D ZG FW CCP
Gubelstrasse 22
6300 Zug, Schweiz
Tel: +41 41 724-3024
mailto:samuel.e...@siemens.com

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