On Monday 30 June 2008, Yi-Neng Lin (林義能) wrote: > We've got a board powered by 405ep running at 266MHz. Now we want to > upgrade the clock rate to 333MHz (model: 3LB333C), can anyone give us > some pointers doing this? I've tried to search the mailing list but > found nothing quite related. Also there seems to exist very limited > ports, if not none, of this model to which I may reference.
There are quite a big number of 405EP board ports. I suspect that some of them are capable of running with 333MHz. The frequencies are usually configured via the I2C bootstrap EEPROM. > Below are questions that are more specific: > 1. For CPU clock rate configuration, exactly what parameters should I > modify? The suspected ones are FWDV (Feedback Divide) and FBDVB (Forward > Divide B) which according to the processor user manual determines the > PLLOUT A. Sure. You need to configure the PLL parameters accordingly. The 405EP users manual should give you all the infos you need. > 2. SDRAM clocking. I guess the clocking should be adapted to something > like 111MHz (given the 333MHz CPU clock); however, the manual shows > there there seems to be only two options, namely 100MHz and 133MHz. Which SDRAM init code are you using? I suggest that you take a look at cpu/ppc4xx/sdram.c and use this file on your system too. You "only" need to configure some SDRAM chip parameters (for example include/configs/zeus.h): /* * SDRAM configuration (please see cpu/ppc/sdram.[ch]) */ #define CONFIG_SDRAM_BANK0 1 /* init onboard SDRAM bank 0 */ #define CONFIG_SDRAM_BANK1 1 /* init onboard SDRAM bank 1 */ /* SDRAM timings used in datasheet */ #define CFG_SDRAM_CL 3 /* CAS latency */ #define CFG_SDRAM_tRP 20 /* PRECHARGE command period */ #define CFG_SDRAM_tRC 66 /* ACTIVE-to-ACTIVE command period */ #define CFG_SDRAM_tRCD 20 /* ACTIVE-to-READ delay */ #define CFG_SDRAM_tRFC 66 /* Auto refresh period */ > 3. Clocking of others such as PCI (on-chip PLB clock, sync/async PCI > clock) and serial port. Are they supposed to be modified accordingly? > 4. Any other parameters? You need to make sure that all frequencies are in range. 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: [EMAIL PROTECTED] ===================================================================== ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ U-Boot-Users mailing list U-Boot-Users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/u-boot-users
