[Arm-netbook] EOMA-68 Carrier Board Concept

[Christopher Thomas]

On Thu, Aug 15, 2013 at 9:20 AM, Scott Sullivan <scott at ss.org> wrote:

> On 08/15/2013 05:51 AM, Christopher Thomas wrote:
>
>> So, Ejectable PCMCIA, 4 Port USB Hub IC, with 2 available external
>> ports, two ports are being utilized for the ATMEGA32U4, and USB Audio
>> IC.
>>
>
> I'd like to catch this now. It has been a major sin of ARM board
> manufactures to only provide USB ports with USB connectors. The Via APC
> boards are particularly bad for this, especial because they have a mini-ITX
> like form factor (called Neo ATX?)[1].
>
>
We are kind of “hamstrung” by the limitations of the 68pins. Most of the
functionality that is being proposed on this board is duplicating features
already present on the A20, but unfortunately, there’s no perfect solution
to replicate ALL the functionality of a standard ATX Platform and still
maintain an affordable and "profitable" system.

Right now, I’ve done some preliminary calculations and consulting with
manufacturers on how much a complete Turn Key system would cost, and if the
volume of the EOMA-68 Card can get down to the more competitive levels
predicted at the onset of the EOMA-68 project, then I feel I could get this
down to a retail cost to the consumer at roughly $70 (That's including the
EOMA-68 CPU Card, obviously less if the CPU Card can be had for $15?!).
Adding in $5 for an extra USB hub IC might not seem like much, but it could
mean the difference between someone choosing the EOMA Platform vs the
cheaper rPI or Panda Board. What you lose in USB, you gain in potential
gains in exponential CPU advancement (Laws of thermodynamics
not-withstanding) and the ability to upgrade, which is not something any
current development system on the market can truly boast. Now, if we wanted
to go with the full blown Development Kit Version of a fully spec’d system
as described by the EOMA-68, on a full size ITX board, that is DEFINITELY
an option, but beyond the scope of what I was proposing, which is an
affordable, easy to produce, open development/experimentation/consumer-esq
device.

Some USB ports should be brought out on the conventional 0.1" headers you
> see on ATX motherboards (or the USB 3.0 equivalent 20pin connector). This
> is especially important if making it ITX case compatible. Cases will have
> front facing ports, and not including a header means any user can not use
> their case to it's fullest.
>

A potential compromise would be to have the ATMEGA32U4 as a jumper
select-able option on the board, with the suggested headers available as
desired, or maybe consider sacrificing some of the GPIO of the EOMA-68
Specification and bring out the 3rd USB Host port of the A20 to the header.



One of the main reasons I chose to locate the holes via the ATX locations
was due to the increase in length. I thought, if I was going to be
increasing the width/length to the standard ITX I/O Panel, might as well
make it mountable in an ITX case, that's not to say it is an ITX computer
though.



I think you are spot on in that some sort of power management is required
(Luke’s Suggestion of the AXP is a good one), as I had intended parts of
the board to be usable even without the EOMA-68 Card inserted. The idea of
having a hot-swappable option comes to mind, or programming the ATMEL chip
via it's USB Bootloader.



> This does mean that you'll either have to choose a Hub chip with more
> ports, or include a second hub. Additionally, headers for front panel
> audio, power/reset switches and LEDs should be considered as well.
>

Headers for Front Panel Audio and Res/Pwr would not be hard, and are a good
idea. Unfortunately, most of the USB3 IC's I found that had more than 4
Ports were about the same cost, if not more than, an additional 4 Port Hub
IC ($11-15 for a 6 port vs $4.67 for an additional 4 Port USB 3.0 Hub IC .
) Quantities would have to be ordered in the 1Ku to be cost effective.

I know I'm missing something, but I think that's the gist of it so far.
Thank you for your input though, this is exactly the dialogue I was hoping
to achieve.




>
> [1]:http://apc.io/
>
> --
> Scott Sullivan
>
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-- 
Christopher Thomas
Firemoth Industries, LLC - Owner
christopher at firemothindustries.com
214-458-5990
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