How to connect 2 FPGA?

Hallo, does anyone has connected 2 FPGA? Which kind of connection have used?

Many Thanks Marco

Reply to
Marco
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"Marco" schrieb im Newsbeitrag news:dn643r$hbo$ snipped-for-privacy@nnrp.ngi.it...

FPGAs are often connected to each other by different means.

your question can have no reasonable answers as you are the only person who know WHY you want to connect the FPGA, and the answer to that question is needed in order to decide HOW. It all depends why and what you are going to achive.

Antti

Reply to
Antti Lukats

A bit less cryptic than Antti : You can connect them by one or more parallel wires. You can implement an SPI on both sides, an 8bit parallel bus with Read/Write, or something elese.

Rene

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Reply to
Rene Tschaggelar

I must develop a system with lots of I/O, about 180-190. My chief don't want use BGA (fg320), but pq208... so I thought to connect 2 fpga pq208.

I think it'is bad... but there are other chances?

Otherwise does exist a BGA adapter for fg320 package to change it into a pq320?

Many Thanks Marco

Reply to
Marco

"Marco" schrieb im Newsbeitrag news:dn6f94$l68$ snipped-for-privacy@nnrp.ngi.it...

ah ok that explains it all.

for several reasons the 2 package deal may be better so your chief has hist point on this.

if you want to lower cost then the 2 package is probably cheaper both from silicon price, board complexity assembly costs, etc..

but it also makes a little additional 'burden' on the design. but its always like this, to get the production cost a little lower it is needed to invest a little more during design.

if you can live with 185 IOs then Altera 1C6 PQ240 has so many ios available! but you need to check the dual purpose pins very carefully. if that is not an options take 2 PQ208 chips and connect some amount of io lines between then, that should be sufficent, you can decide how to implement the interface later. of course you need to partition the design properly so you dont need high speed update over the FPGA intercomm

if you are just a few pins short on the PQ208 it may be reasonable to add a low cost microcontroller that both configures the FPGA (saves a penny here) and works as IO extender later

Antti

Reply to
Antti Lukats

Hi

At a minimum we need to know how much bandwidth and latency you accept/require for the communication between your FPGAs and how much of your FPGAs you intend to dedicate to inter-FPGAs communication. The caracteristics of the FPGA themselves are also welcome.

Waiting for your answer,

Eric DELAGE, Senior ASIC/FPGA Architect EMail: nospam DOT eric AT gmail DOT com Homepage:

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nospam.eric

Many Thanks in advance!

Fortunately I make sure my chief changes his mind toward the use of 2 FPGA. Now we're searching for an adapter for BGA package. I have found this from Interconnect Systems: HiLoTM BGA Socketing Supports Xilinx® Virtex 4 BGA Packages

Does anyone has already used it? Could proive feedback?

Many and many thanks MArco

Reply to
Marco

We used sockets on one board. I wouldn't expect to use them in production, the cost if far to excessive. If you can find a place that does BGA assembly you will find it much better. We have had very good success lately with assembly of boards with PBGA packages

Simon

FPGA.

Reply to
Simon Peacock

one other point.. if you do use a BGA.. put about 20 pins off to a dual row connector... that will allow you debug pins that can't be accessed. Also look at exposing the bottom of vias 'off-chip'... so you can probe signals to find out what's happening.

Simon

lately

of

Supports

Reply to
Simon Peacock

Why not use a FPGA module like the Zefant Modules?

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Uwe Bonnes                bon@elektron.ikp.physik.tu-darmstadt.de

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Reply to
Uwe Bonnes

I have one of those Zefant S3-1000 boards + Baseboard , it's an excellent combination.

There is even 47 pcs. 5v tolerant CPLD pins in addition to the FPGA pins.

Carsten

Reply to
Carsten

It seems good. I'll look for it.

Many Thanks Marco

Reply to
Marco

What reasons do you have for not using BGAs? Any contract manufacturer (who will do the reflow soldering) will quote you **cheaper** on BGAs than quad packs, because they are easier to place. If you intend to sell a lot of them, the manufacturing price becomes important.

As noted, if you need debug access to the pins, bring them out to a header that simply would not be fitted in production.

As to prototyping with BGAs, there are people around who successfully put down BGAs with heat guns.

Of course, you could use a plugin module, but then you expose yourself to the single greatest failure mechanism in all electronic equipment; mechanical connections.

Cheers

PeteS

Reply to
PeteS

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