From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Roese Date: Mon, 30 Jun 2008 14:27:43 +0200 Subject: [U-Boot-Users] CPU (405ep) clock upgrade.. In-Reply-To: <4868CB14.4050807@fiberlogic.com> References: <48687037.3000106@fiberlogic.com> <200806300803.40847.sr@denx.de> <4868CB14.4050807@fiberlogic.com> Message-ID: <200806301427.43270.sr@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Monday 30 June 2008, Yi-Neng Lin (???) wrote: > Thanks a lot for your reply, Stefan. However, in my understanding, only > memory-related info is stored in the EEPROM in the memory module, isn't it? Yes, the I2C EEPROM on the DIMM has of course only memory module related stuff. But I was referring to the 405EX bootstrap EEPROM (see chapter 9.2 IIC serial EPROM controller (IEC) Operation in the 405EP users manual). > The CPU and bus related info is hard-coded in the code. This is what I saw > from my code. Not very sure of it, though. Yes, could be that you are using the fixed, compiled-in speed configuration. > ? I think it's the spd_sdram() [cpu/ppc4xx] who does the job, which could > have been an outdated method. It was renamed and is now called 40x_spd_sdram.c. For board with DIMM modules on 405EP this is the way to go. > The timing info is read from the SPD (Serial > Presence Detect) EEPROM on the SDRAM module. My question is, with the > upgraded CPU clock (333MHz), ordinary SDRAMs (PC100 and PC133) may not be > able to support it, which means I may have to use PC2700 (333MHz; too > fast?) or PC66(66MHz; too slow?). Am I correct? Any other comment or > solution for this? I'm pretty sure that you still can use the "ordinary" DIMMs. The driver should configure the needed parameters like CAS latency accordingly. Best regards, Stefan ===================================================================== DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: +49-8142-66989-0 Fax: +49-8142-66989-80 Email: office at denx.de =====================================================================