[Community] Welcome to new Project: Neo900

[Dr. H. Nikolaus Schaller]

Hi Neil,

Am 02.11.2013 um 09:46 schrieb NeilBrown:

> On Thu, 31 Oct 2013 08:23:29 +0100 "Dr. H. Nikolaus Schaller"
> <hns at goldelico.com> wrote:
> 
>> Hi,
>> the new Neo900 (GTA04b7) project has been started within the OpenPhoenux community!
>> 
>> It is now open for collecting donations to finance the initial development.
>> 
>> For all details, please refer to the project home page: http://www.neo900.org/
>> 
>> Let the Phoenux fly :)
>> 
>> Nikolaus
> 
> Hi,
> I've been reading through the web site and have a couple of comments.
> 
> 1/  From the 3x3 table on the front page:
> 
>           IrDA and Consumer IR
> 
>     Use your phone as a universal TV remote or...
>     connect the serial console via IrDA link. Low
>     level debugging couldn't be made easier.
> 
> unless you know something I don't, it isn't possible to do low-level debugging
> over a serial console on the IrDA link.  Certainly not possible to capture
> early-boot messages.
> For low-level kernel debugging I find a serial cable indispensable.
> 
> Also the "Feature Overview" in neo900-feasibility.pdf has an 'x' next to
> 'IrDA' for both Neo900 possibilities.  I guess 'x' must mean "yes".  I
> usually find "x" to me "no" and a "tick" to mean yes.  Maybe it's a cultural
> thing :-)

Yes, appears to be so. Here we see an "x" like a checkmark "✓" meaning "yes".

> Also the table doesn't list any Bluetooth for the GTA04.  Not even an 'x'.

Oops - that is an omission.

I have fixed the document.

> 
> 
> 2/ In neo900-feasibility.pdf
> section 14 - Dual/Quad-core
> 
> -  OMAP4: yes, Jorjin OMAP4 module, same CPU as PandaBoard; but we donʻt know
>    all hardware details and/or software (power management)
> 
> This seems to imply that we do know all the detail of power management for
> the omap3.  But we do not.
> The power usage on the GTA04 is still woeful.  This may not be directly
> related to the OMAP3 software, but I suspect it is partly related.

What I don't know is if all peripherals are powered down as much as possible.
Suspects are the ITG3200 and the RS232/IrDA drivers.

> 
> In general the issue of power-management is largely missing from the
> feasibility study.  It should really state how power (in)efficient the GTA04
> is and advise that there is no guarantee that the Neo900 will be any better.
> (Anyone know how power-efficient the N900 is?).

Yes, the N900 (RX51) is better than the GTA04. AFAIK, there is no study
discussing why they are such better.

> Also: what are the details that we don't know?  I managed to find a TRM for
> the OMAP4430 without much effort.

Generally the evaluation result is that we know a lot more about OMAP3/GTA04.

But nothing (except theory like a TRM) for the OMAP4. I.e. we could make a
lot of mistakes hooking up the OMPA4 in a way that prevents optimal power
management.

And, if we take the Pandabaord as an example, it has no power management
and therefore we don't have a power-efficiency optimzed blueprint to learn from.

This sums up in that we know the OMAP3 better to optimize power demand than
an OMAP4.

With the current 2-PCB approach it could become feasible to develop an
OMAP4 CPU board later.

Thanks for the helpful comments,
Nikolaus