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Looking for a Design for a Small FPGA Board

Hi, I'm a hobbyist, and about a month and a half ago I made a post to this newsgroup looking for a compact FPGA board that I could purchase online in small quantities for a project I was doing. It seemed that no one knew of a board with the specs I needed (and the closest ones I was able to find were the ones at

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but they were slighty too large for what I needed), so I decided to try and design one myself with PCB design software (EAGLE 4.13). But I have very little experience in PCB design and am pretty overwhelmed with created a design from scratch. So I was wondering if there was a place I could download the design or (in case anyone missed my original post) purchase a board with the following specs:

-FPGA device with at least 15,000 usable gates (more would be preferable). I only need a small number of user IOs, so that shouldn't be an issue at all.

-clock to run the FPGA with only around 4 MHz frequency range... higher isn't a problem however.

-in-circuit reprogrammable non-volatile memory device for storing the FPGA's configuration data, if the FPGA doesn't have one built-in.

-The board's must be able to fit with a 40 mm x 30 mm x 10 mm or less volume (this is important).

I'm planning on just soldering wires directly to the board, so no specific connectors are necessary. And I don't mind if the specs aren't exactly what I need, just so long as they are relatively easy to alter to my specifications. Thanks a lot for any help.

-Darien

Reply to
Daragoth
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To make a complete system, what do you have/want for the system clock? Is there a need for an on-board oscillator?

What about power? Are you supplying a predetermined external fixed voltage? An external voltage to satisfy the FPGA? Several external voltages to match the FPGA's every whim?

Are you expecting your I/O to be 5V tolerant/compatible?

These questions and perhaps a few more might be needed to get the fully working board.

Another thought might be to get a TQFP prototyping board (or adapter) and wire together your own regulators, bypass, and frequency sources. There are

100 pin TQFP packages that are pretty small - the support stuff might take up the most room.

Reply to
John_H

I don't want to be too pessimistic, but I expect it will be very unlikely that you will find a board that is as small as you are asking for. Typically a prototyping board does not have significant size constraints. Instead, a proto board will be trying to fit a number of applications which will require it to be a bit larger than just a chip on a board. 40 x 30 mm is a very small board. We build IO modules as daughterboards on a PC/104 board (already a small foot print) and these are a bit larger than you are asking for. One of our big problems with this format is the lack of space for components.

I think you need to go back to designing your own. Perhaps you can get someone to do the layout for you? I did my own layout for a couple of boards and did not find it so difficult. Is your problem one of being able to route all the signals in a small space?

Can you tell me why your board needs to be so tiny?

--

Rick "rickman" Collins

rick.collins@XYarius.com
Ignore the reply address. To email me use the above address with the XY
removed.

Arius - A Signal Processing Solutions Company
Specializing in DSP and FPGA design      URL http://www.arius.com
4 King Ave                               301-682-7772 Voice
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Reply to
rickman

It sounds as if your best aproach would be to find a sufficiently documented evaluation board that fits your needs , maybe

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(the schematics are downloadable from there) and re-design the PCB to fit your space requirements as you suggested. I'd recommend checking available souces for the parts before deciding on which board to clone, some of the evaluation-board may use components difficult to obtain for a hobbyist.

That should save you a lot of headaches compared to doing everything from scratch.

Good Luck !

Chris

Reply to
Christoph Loew

Hi Darien,

Here is a new board that may meet your needs

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It's dimension is 50.7 x 43.6mm, however if you took off the USB connector, and then used a dremel tool, or a small mill, to route off the top egde and the left edge (no, I'm serious:) ), then I think you may be able to bring it down to your needed size.

You could then solder your wires to the bottom edge connector.

Best regards,

Tony Burch B U R C H E D Simple FPGA Boards, The Most Free I/O, Easy Prototyping

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Reply to
Tony Burch

That's what I really love about this newsgroup, people recommeding products of their direct competitors. Kudos to you, Tony!

I designed the Trenz board. It is layouted in a way that you can cut it in stripes without interrupting the power supply. For a dongle product. At 42mm x 30mm x 3.5mm it will give you 60 FPGA I/O plus configuration and power supply, at 42mm x 20mm x 3.5mm you will have to solder every IO to the board yourself. Are you sure that you can not squeeze it in with these additional 2mm?

You can cut away these 2mm but it will interrupt the main power supply, you could fix that with a wire, but this will result in a really ugly looking board afterwards.

BTW: Can you tell us what it is that you want to build the board into?

Also, does anybody know about a source for generic usb dongle cases? Our quantities are not large enough to have a custom case molded.

Kolja Sulimma

Reply to
Kolja Sulimma

Yeah, I need an onboard oscillator running at a minimum of 4 MHz. Power is going to be coming from two fixed external sources, one at

3.43V and another at 5V.

Where would I be able to find one of these TQFP proto boards? They sound interesting. Thanks.

-Darien G.

Reply to
Daragoth

A google search on the quoted "tqfp proto" came up without a hit but had a couple sponsor links that looked like they might fill your needs:

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and
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.

I don't have a "preferred supplier" so a proper google search should provide you some answers.

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Reply to
John_H

Thanks for the info, I'll definately consider doing so. What are the dimensions of the board you referred to, just so I know how much I would have to reduce it by? I can't check the schematics until I download the software for it. But I wonder if I'll be able to reduce it enough to fit my specifications. Would a double-sided board be the solution?

-Darien

Reply to
Daragoth

Have you looked at the development boards at

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Xilinx only, but the lowest priced ones I've seen anywhere on the web...

Reply to
maxfoo

Reply to
hamilton

Hm, sounds interesting, I might just try that... thanks for the advice.

-Daragoth

Reply to
Daragoth

--snip--

--snip--

Pactec makes several cases that are appropriately sized. I've seen several comercial designs that use their CM line.

Rob Young snipped-for-privacy@ieee.nospam.org

Reply to
Rob Young

This sounds like it really might work... the only concern I have is the height of 20 mm. I noticed there was a pushbutton on the board, is it this that's causing the height. If so, would it be possible to remove it easily? Thanks for your help.

-Darien

Reply to
Daragoth

I believe I've looked at those before... the dimensions of the boards there don't seem to be listed on the website, but from what I can tell they appear to be too large, unfortunately.

-Darien

Reply to
Daragoth

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