Using FPGA to feed 80386

It is not hard to make your own single sided PCBs for DIP packages and the larger pitch leaded surface mount parts. But if you try to do anything beyond that you will find it is quite an effort.

Etching is not the hard part. How do you connect traces through vias on double sided boards? Even trying to do finer pitch parts on single sided boards is hard because there is no solder resist and shorts are very hard to prevent.

Remember, this video was an ad by Jameco.

The solution is obvious: solder material cast into rivets, with a special tool for automated insertion and mechanical compression, with even an optional heated welding as by a separate lower power laser step.

Also, there's no reason a device couldn't be constructed to laser etch both sides at the same time, even post-processong for burn-thrus in liew of mechanical drilling. Use of staggered lasers would also allow faster throughput.

I think there's a business opportunity here.

Best regards, Rick C. Hodgin

A simultaneous parallel laser could burn thru a transparency to provide the solder mask.

An assembly line could even be created to run them N-off in assembled form. Automated deposition of solder paste, physical IC packages, run through an oven, cooldown and testing.

It could all be done in a year from idea to production.

Best regards, Rick C. Hodgin

Minimal. Nearly zero with regards to ICs, and zero related to FPGAs.

Best regards, Rick C. Hodgin

I found these chips available for $10 each. 3.3V fully static, 16-bit data bus.

I am considering them.

Best regards, Rick C. Hodgin

Hmmmmm.... or they could make them the way they do now and save the year! :)

I was asking how *you* would do it at home...

Considering them for what? Are you planning to build something?

Use an online service to get finished boards and solder masks. :-)

If I had money to do so, I would move into this area of profession. Reminds me of welding (you create physical things rather than intangible things as with software).

Best regards, Rick C. Hodgin

I expect it does take a bunch of money to make boards. The equipment is rather expensive. But doing the design can be fairly inexpensive still. It's the debug that requires expensive equipment. Scopes and such can rack up big bucks.

I do have an oscilloscope. Got it in 1996. :-)

Best regards, Rick C. Hodgin

Using high-power lasers which aren't fully enclosed is a recipe for blinding an innocent passer-by. Specular reflections can be unexpected and dangerous.

Saying "oops, sorry" just isn't enough when that happens.

I don't care what someone does to their own eyes. I do care what they (might) do to other people's eyes.

Remarkably little, nowadays. So much so that it really is questionable whether it is worth doing them at home. IMHSHO, the main reasons would be "to see if I can" and "if I need it today".

Low end example: 10cm*10cm double sided, plated through holes, solder mask, silkscreen. Cost $25 for 10 boards. (4 layer $50)

assembly, e.g.

Scopes can be had cheaply, especially second hand. High-speed probes typically cost as much as the scope (>$10k isn't unusual!) Even decent 150MHz passive probes cost $150.

In the first video he held up filter glasses so he has some idea of eye protection.

This looks like a prototype being built in his basement lab.

Best regards, Rick C. Hodgin

If you are thinking of designing circuits and building boards with FPGAs, then here's a couple of test questions. Good answers are /necessary/ but not /sufficient/.

What is the highest frequency in your design?

When would you choose to use 6 layers rather than 4?

What types of decoupling capacitors would you use, where would you place them, and how would you connect them?

What shape decoupling capacitor is optimal?

Warning: there's a *lot* of work and understanding required to get accurate answers to those questions. Poor answers will result in non-working boards or pattern-sensitive boards.

Sure; but I don't care about his eyes.

Motto from BT Labs, prominently displayed on relevant walls: "Do not look into laser with remaining eye". They were /very/ serious about specular reflections.

To me it looks like it's done at his home in his basement. Perhaps it's done somewhere else. Being as it's a prototype, and being particularly filmed for the video, it makes sense that it's all open. I'm sure the final form would offer sufficient protection.

Best regards, Rick C. Hodgin

What makes you think that?

Counterexamples from a 10s google:

Probably 33 MHz to 40 MHz.

I'm guessing: When you need to isolate analog and digital traffic, or when your pin counts are sufficiently high that you need access to a common ground plane that's not closely coupled to the power source.

No idea. :-) Wherever the people on forums like this tell me to put them after they review my design.

Corn kernel shape. :-)

No doubts. The majority of the things I would do would be fabric connection, and in many cases, using existing designs which already have those things figured out, but with different programming in the FPGA for whatever task I'm pursuing.

Best regards, Rick C. Hodgin