bit errors on spitz

Andy Green andy at warmcat.com
Thu Mar 11 16:21:37 EST 2010


On 03/11/10 15:42, Somebody in the thread at some point said:
> Andy Green wrote:
>
>> I saw very similar failures for a long time on our iMX31 based device.
>> Eventually I found a Freescale errata where the RAM inside the USB2
>> macrocell started to make single bit errors below 1.38V Vcore; ours was
>> 1.4V at that time but dipped on CPU load.
>
> Good tip. It seems that nobody ported driver for the voltage control
> chip ISL6271 from 2.4 kernel, and bootloader probably does not set
> correct values.
>
> Datasheet:
> http://www.penguin.cz/~utx/zaurus/datasheets/power/Xscale/ISL6271.pdf

Unless there's more to it in the way the zaurus using it that regulator 
isn't programmable digitally.

Reading about your CF Card WLAN related issues they suck down a good 
amount of power when their radio is up, I would definitely suggest 
monitoring with a 'scope the various rails (Vcore, RAM and whatever it 
is the CF Card is powered by) while putting it under load.

-Andy



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