200Mbps link between FPGAs

How could you know that? My claim was about a crimp connector for specific ribbon cable. Do you know what a mixed signal DIN-41612 connector with M ty oe inserts is?

We had a bunch semi-rigid coaxial cables coming out the back. The boss want ed 10psec granularity, and that was what it took to let him make the claim convincingly - though not all that accurately since there was some 60psec o f rms jitter on the master clock, which we would have been able to fix if t he project hadn't got cancelled (albeit after it has worked well enough to let us document the jitter).

-- Bill Sloman, Sydney

If they do exactly what he wants. Electronic engineering involves a lot of using widely available parts for jobs they weren't originally designed for.

The problem isn't the experience you might have had, but rather your compre hension of what you were doing

We put our own together for the prototypes we built. The shop floor was in the business of producing batches of stuff to be sold, and didn't take kind ly to requests for one-offs. We could get them to do it from time to time, but it took diplomacy.

If they can be used to solve Piotr's problem.

Obviously.

Since he was trying to remember what kind of link he might use, speculation s about the price he might be willing to pay aren't all that useful.

He was talking about linking up fast FGAs, which aren't all that cheap.

DLUNU hasn't got much of an idea what other people might know, and thinks t hat other people have the same kind of problem to the same extent.

But you don't seem to have learned much.

Your confidence is misplaced.

It wouldn't work any better, unless there was a great deal of electromagnet ic interference.

You may have assembled them. I had to rip out a plastic fibre from a protot ype tandem mass spectrometer and replace it with glass fibre because the li nk had become too long for the attentuation in the plastic fibre to be tole rable. I don't tout myself an expert on optical data links in consequence - it was just one more bit of trouble-shooting.

A deluded missapprehension - as you could have found out if you'd looked at my first post in this thread.

t finding out what they might be.

I exploit Google - as any sensible person would. Referring back to the text

-books and application notes that originally informed me wouldn't tell my r eaders anything useful. I can remember how happy I was back in the 1990's w hen I first could get datasheets from the web, rather than having to dig ar ound in a six-foot high bookshelf of data books, which I'd had to persuade visiting sales representatives to cough up. We did buy some of them, but pe ople touting new stuff could usually be persuaded to give us a data-book.

I've still got the Gigabit Logic data book that I got that way in about 198

-- Bill Sloman, Sydney

Bill Sloman wrote in news:55ebbff8-517a-4565- snipped-for-privacy@googlegroups.com:

The same way you claim to know what my depth of understanding is.

You are a blatant twerp. I am a hands on developer with decades of boots on the ground experience. Pretty obvious you only maybe got to watch others make use of such items. And you are clueless on cost too. Easy to draw correct conclusions. Unlike when you try to make one.

Bill Sloman wrote in news: snipped-for-privacy@googlegroups.com:

Looks like what VAX/VMS backplanes used.

DIN-41612 connectors go back a long way. I didn't get to see any with spaces for coax inserts/high current leads until after the VAX was well-established.

That's deluded optimism for you.

And head in the mud.

By which you mean you like to think that.

Another bizarre misapprehension.

You do seem to find it easy to decide that the bizarre conclusions you come to are correct. If they got tested from time to time you might be less self-confident.

You can be relied on to decide that I've got it wrong.

ion package could probably give better information.

If Piotr puts his 2 metres of cable where the customer can get his phone cl ose to it, he isn't being all that careful about his packaging.

Two metres of cable implies a fairly short board to board link, and I'd exp ect the boards involved would all be plugged into a single rack, and that r ack would be packaged up in a metal box which would look quite like a Farad ay cage from an electrical point of view. You might need lots of small hole s for cooling air to circulate through (if your boards run hot, as most of them do).

There are situations where the individual boards might be spread around a m achine, and then you have to start thinking of twisted pairs rather than ri bbon cables and conductive screening around the cable, but that usually mea ns more than two metres of cable.

While the rack might have common cabinet doors in the front and in the rear, these doors would mostly be open during troubleshooting while keeping the phone close to his/her head (and forcing full power due to some of the field is absorbed into the head :-),

RF will propagate nicely through long but narrow slots. A 20 cm long 1 mm wide slot will let 900 MHz in. This can become a problem if the connection between the cabinet and the cabinet door isn't very tight. In practice, this would require Fingerstock between the frame and frame door. In practice, I have very rarely seen Fingerstock used between cabinet doors or with room doors, except in EMP protected rooms. Of course Fingerstock is common in individual equipment boxes.

On Monday, December 30, 2019 at 2:58:26 PM UTC+11, snipped-for-privacy@downunder.com w rote:

lation package could probably give better information.

close to it, he isn't being all that careful about his packaging.

expect the boards involved would all be plugged into a single rack, and tha t rack would be packaged up in a metal box which would look quite like a Fa raday cage from an electrical point of view.

(if your boards run hot, as most of them do).

The famous slot antenna. That's why I said small holes, not narrow slots.

I've seen it around from time to time.

The one problem area which I was aware of was for the Cambridge Instrument Electron Beam Microfabricators, which were notoriously averse to security p eople wandering around with walkie-talkie radios.

The cheap cure there was to tell the customers not to let them do it.

When it messes up a million dollar machine, you can do that. The machine ha d been developed over more than ten years, and some of the older bits were a bit vulnerable. I got stuck with reworking a couple of bits of decidedly primitive engineering which had been more or less okay when electron beam r esists were less sensitive, and we'd had to write more slowly, but weren't really fast enough to do what marketing said they would.

Bill Sloman wrote in news:a91ac0ae-debb-4524- snipped-for-privacy@googlegroups.com:

No, dipshit. That is what you are. And the 'mud' is up your ass. Right there where you have planted your head.

F*ck you, useless Billy.

First I saw was 1986, Macintosh II. The VAX 11/780 used card-edge connectors.

This is more or less the situation. There is plenty of room for the processing unit, but not where the sensors are located. So I need to physically separate them. There are other good reason for doing that, but they are beyond the scope of the problem. The Euclidean distance is not big, but the wiring channels are not exactly where expected, hence the 2m.

For me 2m at this speed is not a short distance, I didn't know that LVDS (the FPGA LVDS, not in general) can be used over a cable that *long*. Since you consistently claim that even the FPGAs should go fine with their built-in transceivers, I will add a buffer just to be extra sure that no mild EMP is going to fry the main chip. Reworking a TSSOP chip is a bit simpler than a BGA...

Thank you for all your input, especially for the USB-C suggestion. That would be even better and is easily available as well.

Best regards, Piotr

whit3rd wrote in news: snipped-for-privacy@googlegroups.com:

Well, what vax vms evolved into.

On the big side. What it evolved into on the small side is MIDS JTRS

The mil boys turned it into a miniature model.

snipped-for-privacy@decadence.org wrote in news:qucrff$14d9$1 @gioia.aioe.org:

snip

The mil boys turned it into a miniature model years ago. Some idiot even had a very old set of cards for one of the original LVT units on ebay at one point. But they were from the early '80s.

This is what SDR has become. The first models were a miniaturized VAX, but it is now pretty advanced past that.

Piotr Wyderski wrote in news:quci61$1mrt$1 @gioia.aioe.org:

That is the modern day hi speed cable, and the connectors are quite tiny.

Being serial, however, does it need to have any 'twisted pairs' within the cable? Or are they differentially paired, which was one of the original discussions?

You have to page down quite a way to the "Signalling" paragraph, but it is tolerably explicit.

There are links to more detailed specifications.

Google can be quite handy, even if DLUNU feels that he is above it.

Bill Sloman wrote in news: snipped-for-privacy@googlegroups.com:

No need to go there at all.

Unlike you, I know what USB stands for.

I thought USB-C had driver chips built into the connectors. Are they transparent or is there a protocol when using USB-C?

I dug around a bit and found the chips are for ID of the cable DC power capability, not driver chips and are optional.

So why did you waste bandwidth asking a question which you could have answered for yourself?

What's difficult about Universal Serial Bus? It's a pretentious and inaccurate title but nobody in the business is going be unaware what the acronym stands for.