SBC with dual CF, as well as LCD and keypad?

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

Translate This Thread From English to

Threaded View
Hello All,

I've been doing some looking around, and I'm coming up empty.  I'm
looking for a little help, or at least a pointer in the right

I'm developing a small app which will be installed in industrial
kitchens (think restaurants, convention centers, hospitals), and the
requirements for the app are pretty small.  We originally decided on
going with a mini-ITX, but want to drop prices even lower by using a
SBC inside an industrial enclosure.  With that in mind, here's some of
the specs:

- Needs to run linux, primary apps being LCDC, Apache, and a JVM.  We
don't care if the processor is ARM or x86 based.
- One serial port which is used for an LCD with a keypad.  IE, we want
at least a 2x20 (prefer a 4x20) with a keypad (probably four arrows, a
back, and an enter) or possibly four arrows and a jogdial (which can
be pushed in).
- One serial port for a modem (either internal or external).
- At least 2 USB ports
- One parallel port (optional)
- A single network port (10 or 10/100, either way)
- Two compactflash cards.  We plan on making one the system, and one
data storage.  We will be sending updates to the system, and the data
storage won't be moved excessively, unless the unit goes belly-up, at
which point the CF can be pulled and put into a new unit.  The SBC
must be able to boot from one card, we don't want DOC.
- 64MB of RAM

I don't mind assembling some / all of these components, but we're
shooting for a complete cost of under $350.  Where to start?

With that in mind, I did have another question ... is there a limited
number of writes to a compactflash card?  If so, what is that limit?

Thanks for your help.


Re: SBC with dual CF, as well as LCD and keypad?
Quoted text here. Click to load it
You could try the advantech 5820. the problem would be the second CF, it
would have to live in an extra PC/104 card.

as for writes, yes there is a limit. use industrial compact flash and
check the write limit. sandisk industrial CF is 2Million erase cycles.

Re: SBC with dual CF, as well as LCD and keypad?
Quoted text here. Click to load it

No it wouldn't. The onboard CF slot is hardwired as a True-IDE slot on the
secondary IDE interface. You could add an IDE-to-CF interface board (a few
dollars only) on the primary IDE interface and thereby get a simple dual-CF
configuration, MUCH cheaper than a PC/104 card.

The PCM-5820 is $235 minimally configured in 1pc qty, add about $10 for 64Mb
SDRAM and it looks pretty good for the OP's budget.

BEWARE of power issues when writing to CompactFlash. The fact that CF goes
through a controller that doesn't have the capability to recover from bad
power glitches on its own makes it a bit risky for highly critical data
logging, regardless of the filesystem you're using.

Re: SBC with dual CF, as well as LCD and keypad?

Quoted text here. Click to load it

That's still quite a bit more than a miniITX solution (especially
using USB flash memory).

The OP's logic of going to SBC instead of miniITX to decrease cost
confuses me.


Re: SBC with dual CF, as well as LCD and keypad?
Quoted text here. Click to load it

Let's look at the actual price difference and see what you get for
your money:

EPIA motherboard with CPU  - $104
64Mb PC133 SDRAM DIMM      - $ 14.75
ATX PSU                    - $ 29.00
CF to IDE adapter x 2      - $ 70.00
Total $217.75

Advantech PCM-5820 with CPU- $235
64Mb PC66 SDRAM SODIMM     - $ 10.50
5V 3A PSU                  - $  9.75
CF to IDE adapter          - $ 35.00

(PCM-5820 only requires one CF adapter because it has one slot
Total $289.50

The difference is $71.95, which buys you a MUCH smaller system
(smaller housing = cheaper), MUCH less EMI, more stable supply, an
exact substitute (ICP WAFER-5820), MUCH less heat and power
consumption, ...

Re: SBC with dual CF, as well as LCD and keypad? (Lewin A.R.W. Edwards) writes:

Quoted text here. Click to load it

$35 per CF-IDE adapter is about twice the cost anyone should pay and
a dual CF-IDE adapter is only $50.  (Yes, a dual is more expensive
than two singles.)

As I mentioned, I'd use USB memory anyway.  It'd be a much cleaner
solution for this situation.  That drops your cost $70 because the
external USB ports are included (at least with the systems I get).


Re: SBC with dual CF, as well as LCD and keypad?

Quoted text here. Click to load it

I've used CF cards as IDE devices in routers and print servers.... use
one on each IDE chain on a miniITX board?


Re: SBC with dual CF, as well as LCD and keypad?
Quoted text here. Click to load it

Unless you intend to do a one-shot-high-volume production I would not do
a complete PC-like PCB design, because these CPUs don't have a long
life-cycle and you will need to do a PCB redesign with your next
production shot. Thus using some standard interface between your own
hardware and the PC hardware will provide a much more promising future.

Doing a research for our project I originally intended to use
PC/104-Plus, but now I think USB 2 or IDE provides more freedom of
choice (I need high volume on this interface).

Quoted text here. Click to load it

Yes. I supposed something about 100.000 to a million rewrites to a block
of data (the card is doing some internal ware leveling / defect block
replacement), but nobody will guarantee this and nobody says how a block
is defined. This was discussed here multiple times in the past. You need
to strictly limit the writes to the medium (e.g. mounting in write mode
only when necessary, to prevent Linux from updating the file-access-time
when reading). Moreover it's known that power down when writing can kill
the card completely.


Re: SBC with dual CF, as well as LCD and keypad?
Thanks for the help.

We've started narrowing down the final solution with a bit of work on
our own, some calls to SBC manufacturers, and of course, this

I'm a bit stuck between solutions from Parvus (LOTS of stuff),
VersaLogic (very nice people, expensive product), and CompuLab (best
pricing, ARM processor).

I've done the number crunching on the mini-ITX vs. the PC/104, and
they are close, very close.  I can actually get within about $30.
However, I would PREFER the PC/104 because I can put it in a smaller
form factor, and I'm pretty sure I know how the system will perform in
a kitchen, even can go the length of a NEMA enclosure.  Mini-ITX LOOKS
like a computer (bad).

Which brings me more, or less, full-circle to where I am now.

It appears that I can do what I need, and I'll roughly need the

- ARM or x86 board with:
  - 64MB of RAM
  - USB connector(s)  [Connects to our app and/or printer]
  - 10/100 LAN port
  - IDE port(s)
- LCD and keypad (serial, or headers on the board)
- PC/104 modem
- Enclosure with access to the LCD & keypad, modem, and ports
- 6-in-1 card reader / writer (USB or IDE)

The goal here is to circumvent the dual CF (which appears to be a
problem) and use a 3.5" USB [internal] 6-in-1 card reader, which I can
plug in a CF card (for the system) and a SD card (for the user data).

Is this better than a dual CF setup?  What about a CF to boot the
machine, and then a USB-keychain device as storage for the user data?
NAND memory?

Where / who makes custom cases for what I'm needing above?  I need
access to the LCD, keypad, and ports, as well as a 3.5" "slot" for the
6-in-1 reader / writer.

I see that Parvus makes some devices, and even does custom
development.  However, our target price is the full system for under
$600 (and the cheaper, the better).  And their cases run about $450.
IE, for us:

- Main Board and cabling, $230 (approx)
- PC/104 Modem, $130 (
- 64MB CF card, $40
- 32MB SD card, $30
- 6-in-1 card reader, $20
- LCD and keypad, $45
- Power supply, $20
- UPS, $60
- Case, ???

SubTotal:  $575 + case

Obviously, the modem is a price KILLER.  The ability to stack as many
as four boards would likely be required, as we may later extend with
PCMCIA (wireless 802.11b) or serial devices.

Further, I did notice that Parvus has a Biometric Fingerprint scanner.
 Any one used it?  If it's not TOO expensive, I'd like to integrate
into our system (we will eventually, anyway).

I'll probably originally be ordering in lots of 100, then up to around
500 at a time within the next ... 2 years, probably.

As always, help is appreciated.


Quoted text here. Click to load it

Re: SBC with dual CF, as well as LCD and keypad?
Quoted text here. Click to load it

Okay. Can I suggest something else here - If you don't need the ATAness of
CompactFlash, why not use the Compulab board with PCMCIA slot option and
allow the user to choose whatever medium is cheapest, via a PCMCIA adapter.
Mostly this will mean using CompactFlash anyway. For your other storage
medium, use an MMC card and bit-bang it on a couple of GPIOs.

Quoted text here. Click to load it

Where are you physically located? We use a metal-bending shop in CT that
does us a painted steel case MUCH larger than you need, with all apertures
laser-cut very accurately and PEM posts inserted to hold the boards, and it
costs us less than $70 per unit in small quantity. I have to think they
could do something in your size bracket for well under $50.

Quoted text here. Click to load it

But why?? It's much cheaper to use a serial-port modem, or a USB modem
even - and they are tiny. You could have a cavity in the housing to hold the

Quoted text here. Click to load it

If battery power is important, forget about Mini-ITX. Forget about Geode for
that matter. The Compulab ARMcore is your platform!

Quoted text here. Click to load it

If you choose the dual PCMCIA option from Compulab, you're still sitting
pretty with a free slot for 802.11b. Or use a USB pod (we use this option).

Re: SBC with dual CF, as well as LCD and keypad?
Quoted text here. Click to load it

Good thought, for sure.  The PCMCIA option would be fine, but it's
going to add about $30 - $40 to the board (for two slots, after the
price modifier).  I like having it for, perhaps, a modem (though, I
don't want to deal with dongles), or 802.11X [later].

In looking more at the CompuLab ARM processor, I see that their NAND
Flash disk doesn't have some of the write problems that CF does, so,
perhaps, it would be better suited to the storage of our data.  With
that in mind, we could boot from the NOR Flash memory (say, 2 MB), and
store our core OS and user data to the NAND Flash memory.

Now, let's say I want to field-upgrade the unit, and send out either
CompactFlash or USB keychain units to have the user's upgrade the
units.  They could (in theory), select "Upgrade software" from the
menu (on the LCD), enter their passcode, and our program on the Flash
Disk could load the new software upgrades from the USB / CF and write
to the Flash Disk.  Not as clean as what we wanted (originally).  Is
this feasible?

Quoted text here. Click to load it

I'm not anywhere near CT :-)  However, that's not a big deal.  I'm in
Lubbock, TX with partners in Dallas and in northern VA.  However,
that's kindof what I'm looking for.  We've looked a injection-molded
plastic in the past, but the development / prototyping costs are
outrageous, even sending it overseas.  I am fairly convinced that a
metal case could be done relatively cheaply.

Quoted text here. Click to load it

Several reasons, but they may not be sound:

1.  We will be doing dial-out as well as dial-in.  USB modems (in my
experience) aren't fully there yet, and can still be quite flaky.

2.  Serial (external or internal, PCI), could be possible, but I want
as few connection problems (with the customer or installer) as
possible.  That said, a cavity in the housing to hold an external
US-Robotics is highly possible.  Which brings the cost down to around

Quoted text here. Click to load it

My main concern with the UPS is that when the power flickers, the
system stays up.  None of the mentioned formats consume too much power
for our usage.

Quoted text here. Click to load it

We will probably go with a single PCMCIA, and if we need more room,
using your cavity idea, internally mount a USB hub.  What do you mean
by using a USB pod?  Everything I've seen about USB pod's are related
to audio (ie, microphone through USB).

Re: SBC with dual CF, as well as LCD and keypad?
Quoted text here. Click to load it

PCMCIA modems with XJack (dongle-less) are readily available.

Quoted text here. Click to load it

Well, more importantly, you can run JFFS or something like that *usefully*
when you have access to the raw NAND. I'd describe it as significantly more
robust than CF. With CF you're always hidden from the real flash by the best
intentions of the card's firmware.

Quoted text here. Click to load it

That's the design intention.

Quoted text here. Click to load it

Sure, there is no reason why this wouldn't be achievable.

Quoted text here. Click to load it

Yeah, it could be thousands for an SLA for a case that size, and definitely
thousands to get a real mold made for injection-molding.

Quoted text here. Click to load it

*shrug* The USB modems I've seen are a standard serial modem chipset with
USB<->serial glue. I haven't had any problems.

Quoted text here. Click to load it

I didn't realize you would be OK with using interchangeable PCMCIA devices.
If you've already got the PCMCIA slots and you don't foresee needing to have
three things (modem, removable flash, 802.11b) all connected simultaneously,
I'd say stick with PCMCIA.

Quoted text here. Click to load it
Quoted text here. Click to load it

I meant use a USB 802.11b adapter. I refer to them as pods, I guess not
everyone does :)

-- Lewin A.R.W. Edwards ( /)
Learn how to develop high-end embedded systems on a tight budget!
We've slightly trimmed the long signature. Click to see the full one.
Re: SBC with dual CF, as well as LCD and keypad?
Quoted text here. Click to load it

If you are on USB you could also use a memory stick which uses an USB
interface without an adapter.


Re: SBC with dual CF, as well as LCD and keypad?
We just released a product based on a Mini-ITX board that provides (2)
compact flash slots, power supply, watchdog, etc.

Got to

Single unit price is $349 (including Mini-ITX board)

Quoted text here. Click to load it

Site Timeline