Wirelessly Connecting two FPGA development boards (Celoxica RC100 boards)

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I am trying to connect two FPGA development boards together. The boards in
question are two Celoxica RC100 development boards. Video in is from an analog
camera. The video data is converted to digital and stored on
SRAM. There is an expansion header for inter-connectivity. On the other board
video out to a monitor occurs after reading data from the SRAM on this board.
Have connected to two boards via a ribbon cable connected to the expansion
headers. Want to replace this cable with wireless or optical transmission. Is
there any development boards available for this. The pixel clock is 10 MHz and
there are at least 16 bits per pixel (32 aftere error correction encoding).
Access to a 80 MHz on board clock is
available. Any help would be much appreciated.

Re: Wirelessly Connecting two FPGA development boards (Celoxica RC100 boards)
Can you explain a bit more?  Are you planning on looking to replace the
Celoxica boards with something else, or do you want to mate the Celoxica
boards to some optical or wireless transmission system?  If so, how would
you want to transfer data to/from the optical or wireless interface boards?


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Re: Wirelessly Connecting two FPGA development boards (Celoxica RC100 boards)
Thank for replying to my post. To answer your first question I want to
mate an optical or wireless communication interface to the Celoxica
RC100 boards.
Set up so far is as follows:

Camera -> Celoxica Board -> Ribbon Cable -> Celoxica Board -> Monitor

The Ribbon cable is connected to the Celoxica boards using the expansion
header on the celoxica boards. This expansion header allows digital
communition in and out of the FPGA on the Celoxica board. The data on
the ribbon cable ha a bus width of 32 (i.e. is 32 bits wide) and and the
data changes every 100 ns (10 MHz). All I want to do is remove the
ribbon cable and replace it with an optical or wireless communication
system (preferably a wireless system). So system would be:

Camera -> Celoxica Board -> Wireless transmitter -> Receiver -> Celoxica
board -> Monitor

One board and the transmitter would be at one end of a room, the other
board and receiver at other end of room. The transmission range is to be
small e.g. max of 5-8 meters. The data rate is fairly high so not sure
if a wireless system would be up to the task. Hope this has clarified my
situation.




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Re: Wirelessly Connecting two FPGA development boards (Celoxica RC100 boards)
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I'm not familiar with what's available in the radio area.

You can get fiber transducers that will do the job.  Look for
gigabit ethernet parts and browse around when you find an interesting
vendor.  The interface is usually differential PECL.

Beware of parts for telco usage.  They will be high power and very
sensitive to get long range.  Expensive.

You have to do a parallel to serial conversion on the transmit
end.  The receiver end has to do clock recovery, serial to parallel,
and also lock onto the byte/word boundaries.

There is actually another level of complication.  The clock recovery
needs enough transitions so you probably need something like 8b/10b
encoding and decoding.

You might find a PHY type chip set that will do all that.  But maybe
that stuff is all included in the big PCI chip now.

If you can't find any PHY chips, consider using several fibers
and doing your own Manchester encoding/decoding.  Decoding is pretty
easy (at least after you see it) if you have a clock that's running
at 8x the bit rate.  You can drop that to 4x for all but the first
FF if you process 2 bits in parallel.  Just use enough fibers
so your receiver can do the decoding at a sane clock speed.

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Re: Wirelessly Connecting two FPGA development boards (Celoxica RC100 boards)
Looks like you have an equivalent serial rate of 320 MHz, plus some sort of
framing overhead so that you can find bit/byte boundries.  You can certainly
do this with an electrical interface over 10m and save a lot of money over
optical.

What time frame are you looking at to implement the solution?  Reason I ask
is that a small company called Core Foundry is finalizing a new FPGA
development system called PROTEUS.  Their intent is to create a modular FPGA
development platform that can be customized to an application simply by
changing removable plug-in modules.  The first incarnation is a small
aluminum box, about 7"w x 9"d x 1.5"h that has room for 4 I/O modules out
the front.  I've seen modules for dual T1/E1 (so up to 8 ports can fit in a
box), a T3/E3/STS-1 single port electrical interface, and a multirate SFP
module with CDR that can handle 30Mbps through 3.2 Gbps.  This might be the
module you care about as it will accept any SFP plug-in, including the
copper GbE SFP modules from Molex and others.

The I/O modules plug into a main board that has a simple serial interface on
it to the outside world.  Behind the I/O modules are connectors to accept
FPGA boards.  A single-wide board connects one I/O module to one FPGA.  A
double-wide board connects one FPGA to two I/O modules, and a quad-wide
board connects one FPGA to 4 I/O modules.  Behind that are connectors for a
more powerful microcontroller board that is optional.  This will have the
10/100, USB and more serial ports on it.  The first uC board available will
be based on soft FPGA cores as opposed to hard uC chips.

The initial FPGA boards will be Cyclones by Altera, as they are readily
available.  All parts sizes will be available.  Spartan 3 boards will most
likely follow next year whenever they are production qualified` and readily
available.  Beyond that they've talked about plans for Stratix and Virtex
FPGA boards, and perhaps some non-FPGA boards with DSP chips, or maybe
combinations of DSP and FPGA.

For your situation, a single SFP I/O module and a single Cyclone 1C3 FPGA
module should suffice.  Probably wouldn't need the uC board at all.  The
FPGA board has ribbon cable connectors on top so that you could cable into
it (with the box lid removed).  Then serialize and format the data and shoot
it out the SFP optical port (or maybe an SFP GbE port, but you'd have to do
more work on the data up-front to make the transcievers happy).  Mapping
your data into an OC-12 payload would be trivial, on the other hand.

The PROTEUS system is in hardware testing now, and I don't know when it will
become available, or at what price points.  They don't have any info posted
on their website yet either, although they say that info will be posted in
October.  I'm looking to be an early customer myself.

I'm not a wireless expert by any stretch, but Infineon makes a nice looking
BT module, ROK104001, that looks like it would make BT simple.  I think in
small qty they are $20 or so.  I heard about it from a local Insight sales
rep.


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