WA: cheap SBC?

Hi,

I'm about to start a new project, and am looking for an SBC to use for prototyping. I need something with a VGA output and an ethernet interface. A CF-type drive or HDD as well. I'd prefer a powerpc board, but it's not a requirement. If anyone knows where I could acquire something like this at a decent price (

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buddy.spaminator.smith
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Reply to
Lewin A.R.W. Edwards

Lewin A.R.W. Edwards wrote: : : PPC boards (that I know of) are just outside your range, starting : around $650. But there is NO problem at all sourcing an x86-based : board with those peripherals. What physical size, etc?

Looking for something small - handheld size. It'll eventually be a small appliance type device.

--buddy

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Reply to
buddy.spaminator.smith

Oh. That's vastly more difficult. Especially since you'll probably want it to be battery-powered. I'd look at XScale PDA development systems. , maybe.

Reply to
Lewin A.R.W. Edwards

Lewin A.R.W. Edwards wrote: :> Looking for something small - handheld size. It'll eventually be a small :> appliance type device. : : Oh. That's vastly more difficult. Especially since you'll probably want : it to be battery-powered. I'd look at XScale PDA development systems.

Actually no. It'll be wall powered. I'm just looking for something that's smaller than, say 8x5.

--buddy

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buddy.spaminator.smith

Oh! In that case, very easy. Look at

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and
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both of them have a range of SBCs in the same footprint as a 3.5" disk drive, both of them will sell you small quantities. Different options according to your performance requirements, starting at 486-class up to much faster systems (the fastest I've worked with in this form factor is 800MHz Via C3; 667MHz and 533MHz Eden variants also available). Many are fanless. All of them have at least your requirements (and more).

Prices start a bit under $200. The boards I've used the most are the WAFER-5820 (ICP) and PCM-5820 (Advantech), which are both 300MHz Geode and are just about $230 each, give or take. Single +5V rail, your PSU should be rated 5A to allow for a hard disk.

My desktop development unit is a PCM-5820 built up in a housing that once contained a 3.5" magneto-optical drive. Overall it's about the size of a regular 5.25" CD-ROM/DVD drive, including power supply, hard disk and slimline (laptop) CD-ROM drive. If necessary I could swap in the

667MHz Via board without increasing the overall system size.
Reply to
Lewin A.R.W. Edwards

Just remember that "fanless" is a relative term. If you put even a VIA

677MHz CPU in a small box and don't have ventilation, it can easily over heat. I seem to recall that they use about ~10 Watts when cranking. That plus a hard drive can make a small box pretty hot.

My VIA 800 MHz came with a CPU fan. I tried running it with the fan unplugged and it got up to 60C or so. If I had stopped the PS fan it would have gotten much worse. That was in a uATX tower. In a small case the temperature would have been a problem for sure.

Reply to
Ralph Malph

Via doesn't recommend fanless operation for anything faster than the

533MHz Eden, and even that requires a pretty large passive heatsink. The C3 is AFAIK explicitly not intended for passive cooling. (I'm trying to avoid the word fanless, because Peltiers are a possibility).

The 667MHz Via chip gets fiercely hot unless you have either active cooling or a very massive heatsink (not a standard product, in the main). Advantech's Via-based boards have a very large, thick, heavy custom heatsink that covers one entire face of the board and contacts all the major chips. They get warmer than you'd think - 40-45 Celsius, especially if you're giving the video chip a serious workout.

A couple of vendors have supplied us with sample boards with 667MHz C3 and a large (2" tall) passive heatsink. These have been barely acceptable in free air. I would not install one in a housing that did not have some kind of force-fed air.

Geode runs a lot cooler. We haven't encountered any situation where active cooling is necessary. Low-profile heatsinks are the norm.

Reply to
Lewin A.R.W. Edwards

I am curious, how low profile? I have seen Geode PC/104 boards. Would this fit inside a stack (0.435" clear space above board)? I expect not. I guess they have to use these on the top of the stack.

I will be selecting a CPU to go with some other PC/104 boards and would like to get one that is not overly hot, but still has reasonable performance (and all the bells and whistles).

Reply to
Ralph Malph

The Advantech PCM-5820 meets that requirement. They use a heatsink that sits approx 0.28" proud of the top of the PCB. It's a little hard to get my micrometer in there to measure it accurately, but that's a reasonably close approximation. Anyway, it's considerably shorter than the PC/104 connector. The tallest parts on this board are the DB9 serial connector, the RJ45 Ethernet jack, and the mini-DIN PS/2 connector. I can send you a photo to illustrate this if you want. The PC/104 connector is on the CPU (component) side of the board, and it is not a "through" connector. The reverse side of the board has CompactFlash and SODIMM SDRAM sockets.

ICP's board uses a larger custom heatsink panel with a separate 486-size heatsin glued on top. e-valuetech (BCM) boards use an off-the-shelf heatsink that sits about 0.75" off the top of the PCB. You couldn't stack anything on top of these.

The vendor photos of these devices usually show them nude, so you can read the pretty numbers on the chips but you can't guess what heatsink will ship on the thing. I hate that. It makes it impossible to gauge what will fit where.

Reply to
Lewin A.R.W. Edwards

I understand what you are saying. So this board can *only* be used on the bottom of a stack. This may be more convenient for debugging our board than one that has to be on top.

I am looking at an Acrosser CPU that they are selling for $104. I find it hard to believe that they sell them so cheaply. Any experence with Acrosser?

I know. You are lucky if the data sheets give the full mechanical info as well.

Reply to
Ralph Malph

I eval'd the AR-B1551 a while ago, but I don't have an ongoing commercial relationship with them.

I read about that $104 board a while back, and vaguely considered making a product around it, but we never got as far as even ordering a sample. As I recall, that board is an obsolete item that they're using as a promotional tool. I don't recall where exactly I read this, so don't quote me on it, but the impression I got was that they geared up for some project that never materialized.

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Lewin A.R.W. Edwards

Hi, have a look at

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bief description:

Sharp LH79520 Processor o ARM720T 77Mhz o 32 Bit System on chip ? 8MB SDRAM ? 4 MB Flash Memory ? Integrated SVGA controller o Display on standard monitor o Up to 800 x 600 resolution o Up to 32,768 colors ? Composite Video output capability o NTSC and PAL formats (*) ? PS/2 Keyboard Compatible Port ? Multimedia Card (MMC) Slot ? RS232 Port ? Demo software included on CD o Open source o Develop using free GNU tools price:199$

Regards, Viron.

Reply to
Viron Papadopoulos

The Revely is nice, but doesn't meet his requirements - no Ethernet, and no CF or IDE interface. MMC/SD cards are not available in capacities approaching that of CF.

Reply to
Lewin A.R.W. Edwards

Depends on what you count as "approaching". It's true CF are usually cheaper for the same capacity, and they tend to be one or two factor-of-two capacity steps ahead. But that's not at all bad, given the fact that an MMC/SD is only a tiny fraction of the physical volume of a CF.

E.g., just today SanDisk is rolling out their 1GB SD card. I have serious trouble seeing how that would fail to be large enough for any remotely reasonable embedded system ;->

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Reply to
Hans-Bernhard Broeker

We use the Acrosser B-1551 in our HMI product. From a programming point of view, its the same thing as the Advantech PCM-5820, and the layout is basically the same. So far, I have heard no complaints about Acrosser.

We did decide to active cool the Geode -- we designed a mezzanine board with a 45mm? fan that sits on top of the processor and pushes some air, because this can go in a really tight can which then goes into an enclosed panel which then goes into a factory.

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Alex Pavloff

Check out the Cogent CSB337 with the Atmel AT91RM9200 ARM920. Should be about $500 and you can get both Linux and WinCE.

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Ulf Samuelsson

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