[SI-LIST] Re: Wireless board interconnect
- From: John Coupland <coupswork@xxxxxxxxxxxxx>
- To: steve weir <weirsp@xxxxxxxxxx>, si-list@xxxxxxxxxxxxx
- Date: Wed, 08 Jan 2003 11:06:53 -0800
Steve,
Answers for your questions:
1. The signals all go from one board to the other
six.
2. Each board is really a module that can be
plugged in/ unplugged independently of the others.
A daisy chain cable across the front of the
modules has been considered but:
(a) it's tacky and in our application there's no
room for it on the front panel.
(b) stub length can aggravate SI and
(c) the ends of the daisy chain need termination
(if it's done in the module, then there needs to
be a provision for selectively terminationing
these signals on some boards and not on others--if
it's done on the cable, then the termination is
not at the far ends of the signal line).
Cabling inside the modules would be quite
difficult in that all 7 modules would need to be
pulled out somewhat together (it would be really
bad if someone forgot about this req't and tried
to pull out only one module).
Regards,
John
steve weir wrote:
>
> John,
>
> Before I can provide a reasonable answer, I have a couple of questions:
>
> 1. Are these signals point to point, point to multipoint, or multipoint to
> multipoint?
> 2. Is your requirement due to a need for galvanic isolation, or a lack or
> connector pins / etch?
>
> If it is just galvanic isolation you are lookinf for, then take a look at
> NVE's GMR isolators. If you need to reduce the wires then the solution
> depends a lot on your answer to 1).
>
> http://www.nve.com/isindex.html
>
> Regards,
>
> Steve.
>
> At 01:41 PM 1/7/2003 -0800, you wrote:
>
> >Gurus,
> >I would like to send 12 signals from one VME/VXI
> >board to 6 adjacent boards without wires. Does
> >anyone know of an optical or electromagnetic or
> >any other means to send/receive these signals?
> >One of the signals is a clock.
> >Data rate is 50 to 100 MHz.
> >Delay between the sending board and the receiving
> >boards is not critical.
> >Delta delay differences between the nearest and
> >furthest "receiving" boards can be corrected
> >for...up to 5ns).
> >Signal skew and jitter, though, needs to be less
> >than 1ns.
> >The boards can have holes for the optical
> >"signals" to pass through.
> >Board spacing is 1.2"
> >All boards are identical, but the sending board
> >can be restricted to be at the end or the middle.
> >Actually, the sending board also needs to receive
> >the signals.
> >
> >Thanks,
> >John Coupland
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