Hello, I can only share the following experience regarding 21065 chip revs: On rev 0.1, code executed from external SDRAM worked only reliably when setting the WAIT register to a value of 4 or higher (as suggested in issue 4 of the anomalies list). On rev 0.3 this workaround doesn't seem to be necessary any more. I also think it was highly dependend on the exact location of the code (SDRAM page boundaries or so), because it didn't occur on all external modules. But if you inserted a new line of code all could change. Setting the WAITs so high disables all burst access to the SDRAM and inserts a "hold cycle" in every read/write, which slows down the machine quite a bit. Though you can change the WAITs during runtime (e.g. before a block write). I also have to admit that the hardware was not custom-built, the rev 0.1 board was the 21065L EZLAB (SDRAM mapped to bank0) and the rev 0.3 board is from Bittware (Spinner). Regards, Michael Andor Bariska wrote: > We just got a board with Rev.0.3 processors, and it works. So I agree > with Kenneth's conclusion. > > Regards, > Andor Bariska > > WEISS ENGINEERING LTD. - Professional Digital Audio Products > Florastrasse 42 8610 Uster Switzerland > phone: +41 1 940 20 06, fax: +41 1 940 22 14 > mailto: web: http://www.weiss.ch > You *can* afford the best > > > -----Ursprgliche Nachricht----- > > Von: Kenneth Porter [mailto:] > > Gesendet am: Donnerstag, 27. Juli 2000 19:55 > > An: ADSP eGroup > > Betreff: Re: [adsp] 21065L and SDRAM > > > > On Thu, 27 Jul 2000 11:24:49 +0200, Andor Bariska wrote: > > > > > I have a feeling that because of its host of SDRAM bugs in > > the Anomaly > > > List, a shared SDRAM setup using Rev. 0.2 doesn't work. > > > > It's not a complete failure, but I wouldn't use 0.2 in an MP design. I > > had some mysterious problems when I tried to run code from SDRAM with > > 0.2, that were very intermittent and impossible to characterize, so I > > couldn't come up with a workaround. We finally banned 0.2 from our > > product and the problems disappeared. > > > > Do note that 0.3 still has a bug involving BMAX, so if you > > have latency > > issues be sure to look at the errata sheet for potential workarounds. > > > > Kenneth Porter > > Kensington Laboratories, Inc. > > mailto: > > http://www.kensingtonlabs.com -- /* michael.haertl DSP Programmer */ |