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

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 direction.

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.


Reply to
Anthony Presley
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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.

Reply to
Ricardo Trindade

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.

Reply to
Lewin A.R.W. Edwards

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).

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.


Reply to
Michael Schnell


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


Reply to
Alan Lythaby

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.


Reply to
Kyler Laird

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 onboard) 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, ...

Reply to
Lewin A.R.W. Edwards

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 newsgroup.

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 following:

- 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

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- 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.


Reply to
Anthony Presley

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.

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.

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 modem.

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

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).

Reply to
Lewin A.R.W. Edwards

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


Reply to
Michael Schnell

$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).


Reply to
Kyler Laird

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?

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.

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.

  1. 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 .

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.

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).

Reply to
Anthony Presley

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

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.

That's the design intention.

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

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.

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

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.


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


-- Lewin A.R.W. Edwards

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Reply to
Lewin A.R.W. Edwards

We just released a product based on a Mini-ITX board that provides (2) compact flash slots, power supply, watchdog, etc.

Got to

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

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