Low-cost embedded mobo

Do you have a question? Post it now! No Registration Necessary

Translate This Thread From English to

Threaded View
I am trying to locate a low-cost embedded mobo that would support
stripped down embedded Linux with

(a) two RS232 ports
(b) one IDE channel (to support a compact flash card as a solid-state
(c) around 32M RAM
(d) processor - 486/66 or better. Speed is not an issue.

No video or networking is required. As long as I can boot with
terminal support over RS232 - that is all I need.

Everything I've been able to find is just too high-end and too
expensive. I need to be able to put together a cased solution for a
dedicated function for around USD200 and the products I've seen are
considerably more expensive than that. Does anyone make anything
suitably 'low end' with a price to match?

(I have to wonder why these embedded mobos are so expensive. I
understand the economics of scale, but when a low-end ATX mobo is
around USD30 you gotta wonder)

Re: Low-cost embedded mobo
Quoted text here. Click to load it

Sorry, you just won't be able to do it at that price; that's life. You
should consider $170 for the motherboard with CPU but no RAM as a
pretty good price. Advantech PCM-4825 is a candidate, 486DX4/100, it's
about $180 or so. Doesn't come down a whole lot with quantity.

Quoted text here. Click to load it

Because (especially in the low end, which is where a 486/66 lies) they
use ancient parts (e.g. EDO-DRAM, C&T (Asilie(a)nt) SVGA/LCD
controllers, etc) and they have to keep stocks of them and/or buy on
the surplus market. Their volumes are also at least a couple of orders
of magnitude smaller than the generic mobo vendors. Plus, the embedded
guys have to maintain more support staff per board sold. It all adds

Mind you, whatever you're trying to do on a 486DX2/66 can almost
certainly be done inside your price budget if you'll consent to a
non-x86 platform and you don't mind rolling your own board. An ARM SoC
with two UARTs and enough external RAM for your needs (and enough I/Os
for your CF card, and Linux-compatible) will only be about $30-40 with
glue, plus a few dollars' worth of PCB acreage. And it will require
much less in the way of PSU.

If this is not an option, your only choice is to use a "reasonably
solid supply" motherboard like Via Epia, which will set you back
around $120. With PSU and RAM, this will be fairly close to the $200
target price just by itself, though.

Re: Low-cost embedded mobo
Quoted text here. Click to load it

You may be able to use the Via Eden mini-ITX mobo. The cheapest ones are
about $95, the CPU is way overkill for your application. I think they even
have one with a CF slot already built-in. Finding 32MB will be interesting,
I guess 64 or 128 is cheaper and easier to find.


Re: Low-cost embedded mobo

Quoted text here. Click to load it

TTBOMK the Epia (original Epia) motherboard with 500MHz Eden is out of
production, the only non-surplus-stock options start with the Epia-M.

Re: Low-cost embedded mobo
Quoted text here. Click to load it


You can easily find pretty cheap EBX-format pc/104 SBCs on ebay.
They have everything what you need and even more and you shuld be
able to find something <$100


Re: Low-cost embedded mobo
ajmayo@my-deja.com (Andrew Mayo) wrote in message

Thanks folks. I had hoped to find something cheaper; it does not need
a video subsystem, for instance, and while I said 486 I meant only
that is the amount of CPU power required,(actually, I probably need
*less* CPU power - this is a real low-end project) - not that it has
to be a 486-compatible OS. Any CPU that I could get a Linux kernel
compiled for would do.

What do I need it for?. Well, there's no great secret here. My company
collects data from clients who run a PC-based application.
Unfortunately for various reasons these folks aren't too good at
remembering to keep their PC on overnight, so that scheduled tasks can
dial in to a central server and collect that data.

What I want is a small black box which will connect to a modem via an
RS232 port and to the PC via a second port. During the day the PC
application can send data down to the black box, which will be powered
independently (I would ideally like to phone-power it, but a wall-wart
will do).

At night the black box will dial in to the central server and download
the collected data. I would prefer to use FTP since that's what we're
already doing with the PC - and thought, well, I could use embedded
Linux as the OS and everything I need will be available pretty much
'off the shelf'.

Since Linux runs just fine with a system console, I can control and
communicate via the RS232 port and use Windows simple ANSI terminal
support as a 'dumb terminal', just like the good ole days. With ftp
client as well, (maybe server, to make it easy to transfer stuff from
PC to controller and back), I would have everything I need.

Memory and CPU requirements are obviously pretty modest.

Now I am a hardware design engineer and yes, I could design and build
something, have the PCBs made and so on (I will want thousands of
units, so its worth considering this), but I am very surprised that I
can't seem to find something half way between the 'tiny BASIC stamp'
kind of PIC-based really low end controllers and the 'tiny little full
PC' mobos which are far too high-end (and expensive) for what I want.

The nearest thing I've found so far is Tern's Flashcore B
(http://www.tern.com/fc_b.htm ) which *might* be able to boot embedded
Linux, with a bit of work. It has a lot less RAM (128K standard) but
on reflection I don't really need much RAM - I will have, say, a 16M
or 32M CF card - dirt cheap - as the main storage. The Tern card is
the right price (USD99) and has the necessary RS232 ports etc.

Looking around quickly on the net, I see a couple of other people
wondering if it would be possible to get embedded Linux running on
this board - it is *just* powerful enough to make this possible.

Anyway, thanks for the comments..... I will keep looking, to see if
anything else is around before deciding to go any further.

Re: Low-cost embedded mobo

Quoted text here. Click to load it

After reading your requirements, I doubht if you really need linux. If
you are ready to write somethign say based on a state machine design,
the number of options is much bigger. I.e. you could use somethign
based on the Rabbit Cores ( www.rabbitsemiconductor.com ) where you
get cores that are even Network enabled (to comunicate with the users
PC's or even transfer your data across the internet instead of using
modems) for close to nothing. These cores start at $22 for non
networked ones and for $32 you get one with ethernet etc. That's hard
to beat with something built on your own! All those have in comon that
you have several ports to do serial IO so even if you want to connect
a modem that's no problem. Another nice thing is that their SDK's
(which are also very low priced) come with libraries to do almost
anyhting including a TCP Stack, libraries to control terminals and
modems etc. etc. So again, IMHO Linux is just overkill for what you
intend to do.

Just my 2 though


Re: Low-cost embedded mobo
Quoted text here. Click to load it

If You want thousands of boards then maybe Cogent can be nice to you and
strip their
CBS337.ARM9 from all the display/CAN etc. stuff.
This has plenty of RAM (32 MBYTE) and 8 MBYTE flash.
The Linux kernel (justr loaded it on my AT91RM9200DK which is similar) is
6-800 kB.
On top of that you may want to have a RAMdisk.
This is stored in flash in compressed form.
I have a few compressed ramdisks which I got from the Atmel ARM CD,
they are 3-5 MByte, so 4-8 MByte flash is probably what you should be
looking for.
Maybe 2 will work, but that is stretching it.
You probably need 2 x your flash size in RAM, so 8-16 Mbyte. I.E: SDRAM.

The Cogent card needs a mother board if CompactFlash is to be supported.
You can use an SD-Card instead, or why not an Atmel Dataflash card.
This fits into the MMC/SD socket, but uses a standard SPI interface.
It is basically a flash chip in a package. Most Flash card standards use
a controller between the flash and the interface, the Dataflash cards do
Also , the dataflash cards are available in 2/4/8 and soon 16 MByte.
The small size makes them of cours a lot cheaper than the 32/64/128 MB

The board has 2 x UARTS and an Ethernet port giving you console, modem and
PC connection.
With some coding , you can connect to the PC USB port as well.
That is not supported by any Linux Driver though.

Quoted text here. Click to load it

Best Regards,
Ulf Samuelsson   ulf@a-t-m-e-l.com
We've slightly trimmed the long signature. Click to see the full one.
Re: Low-cost embedded mobo
Quoted text here. Click to load it

Hmmm... not trying to spoil your fun, but I smell a possible wheel
reinvention here.  I'm quite sure I've seen external boxes of exactly
that type before.  Usually meant for nightly fax sending, but with a
bit of luck, I would guess then can spool ordinary modem transfers,
too.  One such device was called something 'the spiderman fax' or 'fax
spider', IIRC, because it was designed as a central blob with cables
('legs') running out of it in just about every direction.

Quoted text here. Click to load it

I'm pretty sure phone-powering would be forbidden.  AFAIK you're not
allowed to draw any power from the phone line unless a call is in
progress.  So at least during standby (neither the PC nor the black
box is active), you would have to run off a wall-wart or maybe an
accumulator powered by the PC.

Hans-Bernhard Broeker ( snipped-for-privacy@physik.rwth-aachen.de)
Even if all the snow were burnt, ashes would remain.

Re: Low-cost embedded mobo
Hmmmm..... sounds like you need Ubicom
I know these people http://www.sxdesign.com/ do magic with them and in
general connected projects of these type seem to fit them like a glove
.But I heard their SDK is stupidly expensive :-( and they only talk
about you for high volumes.

their only fault is they don't do ARM :-)

ajmayo@my-deja.com (Andrew Mayo) wrote in message
Quoted text here. Click to load it

Re: Low-cost embedded mobo
Quoted text here. Click to load it

In stead of asking them to strip down the board for you, why don't you
have someone build it up from the CPU.  The At91RM9200 has Flash (MMC, CF)
controllers, USART and Ethernet build in and goes for around $30.  
If you don't need the flexiblity of the CBS337 hocks, a simple four layers
board (due to the BGA packaging) can be done for less than $100.

Quoted text here. Click to load it

Re: Low-cost embedded mobo

Quoted text here. Click to load it

Maybe six layers... It is quite small pitch on the package.
I don't see the big difference in stripping down the board  (removing the
unwanted chips) and
building it up from scratch.
Maybe you can make the board soemwhat smaller, but you then have to pay more
in development,
and if volume is high, then a custom layout could be part of the "strip".
Key is that there is an existing board, which has gone through the debugging
meaning that Cogent should be in excellent position to do something cost
effectivvely and quick.

Best Regards,
Ulf Samuelsson   ulf@a-t-m-e-l.com
We've slightly trimmed the long signature. Click to see the full one.
Re: Low-cost embedded mobo
: ajmayo@my-deja.com (Andrew Mayo) wrote in message
: Thanks folks. I had hoped to find something cheaper; it does not need
: [SNIP] Any CPU that I could get a Linux kernel compiled for would do.

I suppose the Axis 100LX based developement board/case would do then.
(Axis are the same folks that brought you the Linux WebCam.)

The 'ETRAX 100LX' CPU is their latest offering which now sports a MMU
capable of running plain Linux. It is offered either as an bare CPU
or else as an Multi Chip [BGA] Module composed of CPU + RAM + ROM.
Axis offers development boards for both variations:


Axis indicate that they will give volume discounts. And given that
their 'Axis Device Server Platform' has a starting price of $259
ready encased, it ought to be within reach of your budget.

One possible grivenace would be your HDD requirement.
(If you can not make do with 8MBytes of SDRAM, which is to be
 shared with the Linux kernel + Apps) The developement board
has no ready built HDD interface, but the CPU itself has two
IDE channels or two (narrow) SCSI ports onchip. These ports
are available on pin headers on the developement board, as are
the IEEE-1284 and GPIO ports. Given your statement that you
are an HW engineer, it should be possible for you to expand
upon this board. The board schematics are provided.


  Never ever underestimate the power of human stupidity.
We've slightly trimmed the long signature. Click to see the full one.
Re: Low-cost embedded mobo
ajmayo@my-deja.com (Andrew Mayo) wrote in message
Quoted text here. Click to load it
Well, since that post I have looked into the idea of a VIA Micro-ITX
board-based solution. The low-end boards are around GBP60 including
processor (but without SDRAM) which compares rather favourably with
all those other embedded controller boards, but they are a full PC,
and cases with power supplies are also available for around GBP50.
This is more power than I need but the tradeoff is my development time
gets cut to ribbons as all I have to do is cut down Knoppix (or use
Damn Small Linux), boot off a USB memory key and just set the unit up
with the subset of Linux that I need.

Interestingly, I'd guess that when the Nano-ITX boards start arriving
the embedded systems market might get a bit of a shakeup. If you're
two guys in a garage with a cool embedded systems idea you could use a
Micro ITX or Nano ITX mobo as the base for an embedded Linux project
and your toolset and OS licensing and deployment costs are zero. Also,
hey, its a standard PC, so peripherals etc. are cheap and easy to
interface. The Nano ITX standard (12 X 12cm, if I recall) is really
going to be a very attractive alternative for a lot of embedded
systems where, to be honest, I think the hardware and tools are
looking a bit overpriced. No more emulators, either. Its a PC, so you
can develop and debug on it directly.

I think VIA are on to a winner here. Sure, the low end processors
aren't overpoweringly powerful compared to a standard Pentium/Athlon
but compared to many of the embedded systems processors of choice they
are not too bad. The huge advantage of having a standard PC
architecture means that unless power and size issues are critical,
many embedded systems could just move to this platform and, even more
advantageously, you're not locked into a single source vendor medium
term because the platform (and of course the tools and OS) are built
around industry standards. With networking, USB, serial and parallel
ports as well as VGA video all built in, and a standard IDE channel as
well, life is really simple.

As the power of the fanless processor models continues to improve -
and I would guess that the 'sweet spot' is around the equivalent of,
say, a 1.5G P4 or thereabouts - then we have 'good enough' processor
power for almost anything you might want to build. Now we need to get
the processor power dissipation down, for that performance, to maybe
the 5W level and total mobo power dissipation, without peripherals, to
10W or so. At that point I can't imagine many embedded systems you
couldn't build with something like this (apart from, of course,
battery operated or power-critical systems - but that area normally
goes hand in hand with custom-built PCBs etc.)

Re: Low-cost embedded mobo

Just noted the TERN reference, so thought I'd speak up really briefly

First, I'm not really familiar with the Micro-ITX/Nano-ITX solutions,
so I'll leave the direct comparison work to you!  Based on our
experiences, most hard embedded customers don't really take advantage
of the PC-compatibility of these systems.  They aren't really
expecting to interface to IDE/PCI/VGA devices, not if it comes at an
expense in terms of size, power consumption, or price.  Heck, you talk
about being happy to find a power supply integrated unit...
(presumably with fan and all)... well, how about choosing a board
where you don't need a fan-cooled, half-foot long power supply at all.

I agree with the others that embedded linux isn't really what you're
looking for.  We've looked at some of the hard embedded solutions, but
by the time you strip a kernel down to the point where it can fit in a
couple hundred KB SRAM, you're losing much of the compatibility
advantages of using Linux.  Not many applications (nor even kernel
drivers) are going to be able to run... so I don't think it buys you
much in terms of application flexibility.

We *are* working on a larger 4/8 MB hard embedded board that'll still
be, price-wise, in the low hundreds... but even then, I really
question the attractiveness to the small OEM market (which we define
as falling in to the 50-1000/units per year range) of such a product.
It'll probably be used for small-scale prototyping/educational

From the TERN product line, if all you are looking for is strictly
C-programmable RS-232 ports (including support for real-time clock),
then I'd say the FB isn't a bad choice at all.  You get the CF
interface for direct storage, you get low power consumption (120-140
mA @ 5V), 2 RS-232 ports, etc... for $99 in single quantities, and as
low as $34 in OEM quantities.  If development effort is something
you're concerned about... I personally believe it'd only take you a
couple weeks to get the first version of this app completed, debugged,
and deployed (assuming normal learning curve).

The other primary advantage of Linux you named was the development
advantages.  True, you *are* going to be stuck to a single source if
you go with a vendor like TERN, but considering this particular
application... how significant is that constraint?  This sounds like a
build-once, deploy, and forget type of a thing, and no need to
over-plan (or over-pay) for flexibility you'll never need.

And whether it's TERN or Z-World, this class of 8/16-bit
microcontrollers aren't debugged in emulators like you see from PLCs
either... code's downloaded to the board, executed on the board, and
directly debugged from the board.  Not very different from
cross-development debuggers if you were working with "normal" desktop

As far as the remote download side of things... a couple of options
there as well.  We do have several Ethernet-capable products, and
there's also a little peripheral from eDevices that I've used in the
past: RS-232 interface, integrated SMTP/FTP (over PPP) with dialup
modem unit, all in a small case, for (I believe) under $100.

Just my thoughts on the subject; feel free to contact me if you have
any questions.

ajmayo@my-deja.com (Andrew Mayo) wrote in message

Re: Low-cost embedded mobo
snipped-for-privacy@tern.com (Chon Tang) wrote in message

Thanks for your very helpful comments. A couple of points I would
make, though.

Quoted text here. Click to load it

Actually the power supply for these cases is a small external laptop
switching power supply, which has no fan - just a small plastic
'brick' - the total PSU rating is only 55W which is adequate for the
mobo plus a couple of standard peripherals.

Quoted text here. Click to load it

If I go down the Micro-ITX route, then I have enormous room because
128M SDRAM is only about USD20, so stripping the Linux kernel then
doesn't become such an issue. I am considering booting off a USB pen
drive, and these are also becoming very cheap at the 128M size.

Quoted text here. Click to load it

I think this is the problem though. USD99 is already more than the
Micro-ITX mobo - I can source these retail at GBP60 and probably get
them in qty 100 for GBP40 or so (that's maybe USD60); this is why I
think that these are going to change the face of embedded system
design. Remember, that gives me a C3 533Mhz processor, full VGA built
in, one SDRAM slot, one PCI slot, an IDE channel, 2 serial, 2 USB and
a built-in 10/100 LAN. That might be more than I need right now but
look at the price point!.

I am sure the Tern products are a very fine choice but looking at
total development and integration costs, I am increasingly convinced
that a large chunk of the embedded system market is going to go over
to Micro ITX and Nano ITX PC-compatible mobos, the economics just
looks too compelling.

Re: Low-cost embedded mobo
Quoted text here. Click to load it

The bottom line is: You've told us you have problem X, and you're
getting suggestions based around that. If you really mean "Someday I
will have problem Y and I want to be able to solve that problem
without ever having to change the hardware" then the suggestions might
be different.

What you have to ask yourself is:

1. Will customers with old units already fielded be interested in
whatever new bells and whistles you can come up with in software
upgrades, or are they just paying for hardware they'll never use?

2. Are you sure that you're *ever* going to need any functionality of
Linux, or the mini-ITX solution? Is it likely that upgrades to use
such functionality will correspond to major product line remakes

If your customers are willing to pay $400 for a unit that does X,Y,Z
functions (ONLY), then what sounds more sensible: spend $50 build cost
per unit on an optimized solution and make $350 profit, or spend $150
per unit build cost, make $250 profit, and hope that future software
upgrades will earn you >>$100 net?

Quoted text here. Click to load it

$60 - motherboard
$15 - PSU
$20 - RAM
$20 - bootable media

$115 + housing.

Your route also has complications with EMI (it's a big, fast circuit),
and appallingly high power consumption for the described application.

Remember that mini-ITX hardware follows *PC* life cycles. In 6-9
months you will not be able to buy absolutely identical hardware. In
12-15 months you will probably need minor mechanical rework to fit
whatever is on the market. In 24 months you most likely will not be
able to buy one single part that is in today's design.

I'm not saying Tern's products - or indeed ANYONE's products - are the
answer - I think a cheap all-in-one microcontroller would be way more
than you need, and it would have a total BOM of $40 or so including
housing - but I hate seeing a really suboptimal solution being used
when there is really no justification beyond a vague assertion that
"it might be useful someday".

Re: Low-cost embedded mobo
snipped-for-privacy@larwe.com (Lewin A.R.W. Edwards) wrote in message

Quoted text here. Click to load it

You make a lot of good points.  Long term stability of design can be
very important.  Good luck finding a PC motherboard identical to the
one you bought 5 years ago, unless you're searching on eBay or surplus

The ultimate answer is (of course) application specific so only Andrew
knows for sure what will work for his design.  As much as I'd like to
believe our product is always the right choice, sadly, I have to admit
sometimes that isn't the case!

I hadn't seen the micro-ITX before, so it's an interesting read.
Fundamentally, these are intended for very different applications
(which is basically what you were saying in your post).  Technology
wise... totally different world.  We have customers that primarily
need parallel and analog I/O, drive small solenoids/relays, interface
with small kpad/lcds, etc... and do it with minimum power at minimum
size (2.1 x 2.35 inches and 130 mA @ 5V, compared to the micro-ITX
board at 6.8 x 6.8 inches and.. probably many times the power).

For most of our customers, the mini-itx would not be a viable

Even from a price perspective, I don't think this will compete in the
same market.  Clearly VIA is already producing these in volume (and
pricing it that way for retail customers), and I doubt they have much
margin left for significant OEM discounts.  Andrew, I even question
the GBP40 pricing you guess for 100 units.  The FB is a firm $79 @100
units (and $34 @1000 if you get ambitious), and there are many other
similar products in the same price range.

But I really don't know how PC (or these sub-PC) manufacturers price
their products these days, so maybe you're closer than I am... I'd be
interested in hearing the number when you get a firm quote from them!

But back to the practical matter at hand... I did notice that these
VIA mobos only support 1 serial port.  You'll need to use USB/ethernet
for your PC/modem connections if you go this route.  I'm not sure, but
I doubt the system is bootable off your USB storage.  You'll probably
need some kind of IDE boot device... although you can probably pick
those up at relatively low cost as well.  All in all, a fun hobbyist

You definitely have a lot of options, Andrew!

Re: Low-cost embedded mobo
Quoted text here. Click to load it

The lowest-end EPIA board, with a 400-someMHz Eden processor, requires
about 3A on the 3.3V rail, 400mA on the 12V rail, and 1A on the 5V
rail, IIRC. The multi-rail requirement is also very irritating.

Quoted text here. Click to load it

In the USA, the lowest-end board (out of production, I believe - it's
a special order now) was just under USD100 qty 1, and prices went down
to $70-odd in 100s IF you could get set up with the distributors. Not
possible to obtain it at retail in that price bracket.

Quoted text here. Click to load it

The BIOS, like most modern implementations, supports booting from USB
floppies, which includes USB "pen disks".

Re: Low-cost embedded mobo
snipped-for-privacy@larwe.com (Lewin A.R.W. Edwards) wrote in message

Quoted text here. Click to load it

This thread is probably already dead... but just for later reference,
I did check with the folks at mini-itx, and they quoted me 58.50 at
qnty 100.  That's less than a 5 saving from the qnty 1 pricing, and
equivalent to about $97USD.

Site Timeline