[Arm-netbook] EOMA-68 Carrier Board Concept

[Christopher Thomas]

On Wed, Aug 21, 2013 at 4:47 AM, mike.valk at gmail.com <mike.valk at gmail.com>wrote:

> 2013/8/15 Christopher Thomas <christopher at firemothindustries.com>:
> > Good Morning everyone,
> >
> >    I spoke to a few of you recently and explained a little of what I had
> in
> <snip>
> > the works for our project. open to opinions.
>
> Great news. This board would also make an excellent base for a multi disk
> NAS.
>

In order for this to really function as a dedicated NAS, different design
considerations would have to be considered. Albeit, the footprint is
suitable enough to fit the required components into to make it workable,
the types and quality of components currently being used/designed with are
not what I would really consider reliable NAS grade.

>
> What I'd like to see added: A SATA multiplier.
> As this board is the jump to a desktop PC, One usually wants/needs
> multiple SATA devices. A optical drive and a hard-disk. Perhaps a
> second hard-disk for backups. An E-Sata port (that's just a cable
> away) for hot-swapping.
>

I like this idea, at least in terms of multiple disks, however, the primary
emphasis is to provide a very streamlined, minimal, but very functional
development platform that can be both a standalone system, or embedded with
as few requirements and/or components necessary to make it such. I do have
plans for a full-scale desktop class motherboard, but that is after this
smaller, more affordable platform can be built.

>
> Also a few pinouts for SATA/Molex power connectors . This would
> eliminate the need for a full ATX power supply. And laptop style
> adaptors with SATA power connectors are nowhere to be found and need
> custom builds and result in two power supplies.
>
> Add and option to recieve power from a ATX power supply. For those
> wanting to convert there old pc's or want a cheap and widely available
> power supply.


While not a bad idea, and worth looking further into, is beyond the initial
scope of this project (re: ATX connector).
I DO have an additional power-input header in the current design spec
available on the "interior" of the board.

Rather than include an on-board ATX socket that would require much more
design considerations and engineering over-view, we could include
instructions, or ship as an option, a very "simple" ATX Dummy Plug that
shorts PIN 14 to COM, allowing anyone who DID wish to use an ATX Power
supply to use the MOLEX conectors to power the board.


> Further perhaps a bigger USB hub: 7ports or more whould be nice. Oh
> wait chaining two 4port hubs leaves 7 ports, Doh. I always found 7 to
> be such an odd number of ports. Also leave the internal USB as pin
> headers. That way standard enclosures(parts) can simply tap into the
> pins. And pin to USB-Female are widely avaible. USB-Male to pin header
> are not very common.
>

There will be a total of 6 usable USB Ports, 3-USB 3.0 external, 2 - USB
2.0 Headers Internally, unpopulated, 1 - USB-OTG on the EOMA-68 Card.


>
> Personnaly I'd stick to the STM32x for board I/O.
> 1. Hacker community is already gearing up to those ARM.
> 2. You can reuse code from the flying squirrel
> 3. The EOMA68 (b/h)ackers already have info/knowledge on the STM32x
> from the flying squirrel.


I agree actually, after looking at the current "next generation" of Hacker
Devices, and with Luke's suggestions of both the STM32x and the McHck
(MK20DX32VLF5), they look very appealing.

price = sessionStorage.getItem('price');
MK20 = "MK20DX32VLF5"; //need to spend more time comparing, but this so far
is the cheapest, albeit less GPIO than the STM32F103RBT6.
STM32x = "STM32F103RBT6";
MCU = null;

 if( price <= "1.40") {
   MCU = MK20;
}
   else{
          MCU = STM32x;
               //if someone can link me to a source (off-list) for under
$1.80, I would appreciate it.
               //Cheapest I could find was $2.12 in Qty 1000.
   }

In looking at the ARM Options, and comparing the price/performance of the
M3 vs M4, I think the M4 (notably the Freescale chips) would be the best
option at the moment if anything because I can get them here in the US for
less than $1.60 in Qty 1000. I've got 5 - MK20DX128VLF5 enroute for
delivery Friday. That said the STM32f series has a very mature community
with loads of documentation.  I'd love to hear more input from everyone
else, pro and cons of both.

 I initially chose the ATMEGA32U4 for ease of integration into the Arduino
community, and I had already had schematics drawn up for it. However, with
devices like the Freedom Board, Udoo, and MapleBoard, I have seen the error
of my ways.

That said, it should be noted, I was able to find the ATMEGA32U4 for sub
$1, but for an extra 60-80 cents and not very much increase on BoM
requirements, both the STM32F and MK20D would be worthwhile improvement.



Good luck
>
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-- 
Christopher Thomas
Firemoth Industries, LLC - Owner
christopher at firemothindustries.com
214-458-5990
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