[Arm-netbook] EOMA-68-A20 Card, RTC?

[Ken Phillis Jr]

On Fri, Aug 16, 2013 at 12:09 PM, Henrik Nordström <
henrik at henriknordstrom.net> wrote:

> fre 2013-08-16 klockan 16:50 +0100 skrev luke.leighton:
>
> >  well the question we asked ourselves was: is it acceptable to let an
> > unpowered CPU Card just lose its time setting after say e.g. 24 hours?
>
> To me it's entirely acceptable if the CPU card looses all sene of time
> at power off.
>
> But I would not like my tablet or laptop to loose time only because I
> suspended/hibernated..
>
> So RTC function belongs in the I/O board, but I don't see it as a
> mandatory requirement. Instead it depends on the application
>
>
I believe that the current behavior of the device is to loose all time when
the power is completely cut off. This leaves the behavior I can figure out
as follows...
* The RTC functions are kept if the eoma card is put into suspend/hibernate
and the power source is still active the card will not lose power. This
means that the battery did not die or more accurately the power source is
uninterrupted.

* The RTC functions will halt if the card has  clearly lost if the power is
lost during the hibernate/suspend period. This means that the battery runs
out of power or the power source is completely lost.



> - "consumer" device that uses time as part of normal application
> (tablet, phone, laptop, ...), RTC support is mandatory.
>
> - Server/router type device. Optional, just as having a screen, USB
> port, storage etc is optional.
>
> but not ruling out the use of a CPU card provided RTC either.. these are
> quite common part of modern SoCs, and do not really require that big
> power buffer to keep time for some noticeable time, but if I/O board do
> have an RTC and it looks like it has a sane time then it takes priority.
>
> What certainly needs to be standardised is how to discover if the I/O
> board do have an RTC, and how to address the RTC to find or set current
> time.
>
> Regards
> Henrik
>
>

I think most devices will probably have an separate RTC like what is seen
on the Tablet that is being created right now. This is because the separate
rtc will be able to use less power and thus have a higher chance of keeping
time longer.
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