Low-cost embedded mobo

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.

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 up.

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.

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.

Rob

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

[...]

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

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

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.

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 (

) 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

Markus

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 not. 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 cards.

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.

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Best Regards,
Ulf Samuelsson   ulf@a-t-m-e-l.com
This is a personal view which may or may not be
share by my Employer Atmel Nordic AB

Hi Andrew,

I can recommend my company and products....

Best Regards,

Soren Kristensen

Soekris Engineering, Inc.

5400 Soquel Avenue, Suite E Santa Cruz, CA 95062-7803

Phone (831)464-5375, Fax (831)462-0946

Andrew Mayo wrote:

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.

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.

--
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... snip ...

I wouldn't, when you don't know enough to avoid top-posting.

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Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
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     USE worldnet address!

Maybe you should ask why people top-post? Perhaps it requires less reading?

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Hmmmm..... sounds like you need Ubicom

I know these people 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 :-)

If you knew how to quote, how and where to answer, all of everybody's troubles would be over. But that would be a perfect world, I guess?

See how I quoted your answer, and how much clearer it is to follow a thread this way? Are you too lazy to do this, or did Microsoft (the very clever creator of "top-posting") screw you up this much?

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.

the

not

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 phase 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
This is a personal view which may or may not be
share by my Employer Atmel Nordic AB

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.

--

  ******************************************************
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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.)

Andrew,

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

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 purposes.

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 PCs.

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.

snipped-for-privacy@my-deja.com (Andrew Mayo) wrote in message news:...

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

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.

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.

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.