[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xylo-SDR] Some design thoughts requested

I looked for quite a while and did not find any breadboards using this connector, this style board is a good idea if you are not going to have very large boards. But like you mentioned there would be a need for a motherboard and a some breadboards. Either a group purchase or at least someone that can layout the boards makes the files available so we could order our own boards. Actually a group buy would be way cheaper, but also have the art available as a starting point for any new design.
As far as connectors, if you put a lot of them, lets say .25" apart, you can chose where to put a socket and have narrow or wide spacing according to the project needs. One motherboard for all occasions.
As far as grounds in-between lines, you don't always need that, if you have a group of signals that change together then they can be grouped together without interference, clocks though need to be kept away from control or data signals.
You should have a could of connectors at the end of the bus that are not bussed except for power and grounds, the other pins should have pads.
The bottom line if you make the art available, people can make custom versions that have a section that is compatible with everyone else's, and a custom side if needed.
Either something like this or the Eurocard is workable, the Euro has the advantage that there is a huge selection of already available cards, cages, and motherboards. 

At 05:14 PM 1/3/2006, you wrote:

Phil

Thanks! I'll take a look at this again. The only reason I did not proceed
along this track, is that "Hunt as I might" I could not find commercial
riser cards, and symstik had too few connections. Even If I did find a riser
the spacing would be too close. The sockets are available, but we would have
to design our own motherboard. I don't think is that farfetched an idea
since we could define the spacing and put the raw voltage regulators (5, 12,
and perhaps -12) on the motherboard.

I am sort of tired of sending out stuff without the forthought for
packaging. I think in this project it is especially important, since we can
do A LOT of things with the PGA if we think about the project design from
the outside - in, and create something which can be an anything design based
on the FPGA like a Scope card, a Spectrum analyzer card, a Radio etc!

I think that 184 pins should give us all we need even if we ground every
other pin for better noise immunity.

Comments?

Eric




-----Original Message-----
From: xylo-sdr-bounces@lists.ae5k.us [mailto:xylo-sdr-bounces@lists.ae5k.us]
On Behalf Of Philip Covington
Sent: Tuesday, January 03, 2006 1:12 PM
To: Xylo-SDR Discussion
Subject: Re: [Xylo-SDR] Some design thoughts requested

Hello all,

I considered using DDR SIMM sockets for a project.  You get 184
contacts and they give you a card width of 5.25".  The height of the
card is not restricted (within reason).

http://www.molex.com/pdm_docs/sd/876362002_sd.pdf

It is kind of like the SIMMStick idea, but with more contacts (184 vs
30).  30 pin SIMM sockets are very hard to get these days and I see
that Molex has scheduled the 72 pin SIMM sockets for obsolescence.
The DDR DIMM sockets should be around for a while yet.  They are
relatively cheap ($1.92 ea Digikey).

73 de Phil N8VB


On 1/2/06, Eric Ellison <ecellison@comcast.net> wrote:
>
>
>
> Cecil
>
>
>
> Yes, I'll go back and look at Eurocard standard. This looks great. GUD
> HUNTING! Thanks for all the links. One way or tother I think we need a
buss
> for our end product. Your point about size of the boards we might want to
> manufacture is well taken. They should be able to go on a little more than
a
> postage stamp, and be VERY inexpensive to produce - external connectors
> being the limiting size factor! One reason I was looking at Memory Chip
> risers.
>
>
>
> I moused around a little today, and really can't see where I can justify
> Eagle Software in any serious production version. So I'll probably monkey
> around with Kicad, which is a really nice GPL product. I mentioned earlier
> that there was some problem with the Drill files, which they have
corrected.
> Only benefit of Eagle IS the plethora of template files available. I don't
> mind eating on my lunchtime and creating new parts! Good exercise and I am
> getting fatter! (No Testosterone!)
>
>
>
> Sparkfun has a pretty good batch deal for prototype boards and also a lot
of
> interesting new products. I like their little 3 buck power supplies. Also
> have a some 28 pin SOIC to DIP experimenter stuff for about the same
price.
>
>
>
>
http://www.sparkfun.com/shop/index.php?shop=1&cart=525299&cat=1&PHPSESSID=ab
ce58b426cb8d0d0c3cf4b1495f0312
>
>
>
> Other prototype boards can be had at:
>
>
>
> http://protoboards.theshoppe.com/index.html
>
>
>
> Will return!
>
>
>
> Viva the Project
>
>
>
> Eric
>
>
>
>  ________________________________
>
>
> From: xylo-sdr-bounces@lists.ae5k.us
[mailto:xylo-sdr-bounces@lists.ae5k.us]
> On Behalf Of KD5NWA
>  Sent: Monday, January 02, 2006 2:06 PM
>  To: Xylo-SDR Discussion
>  Subject: Re: [Xylo-SDR] Some design thoughts requested
>
>
>
>
> I'll second the DIN connectors,they are very reliable, and come in
different
> sizes, single, and dual connector cards. I have used them in an industrial
> environment and they worked flawlessly for years. But I'll go one more
step
> forward.
>
>  The Eurocard standard allows for mix of one 96 pin connector,  two
> connectors or even three connectors (not needed). Prototype boards are
> cheap, most PCB houses have specials on Eurocard size boards. Card cages
are
> available for low prices for the Eurocard format
>
>  Like Leon said the connectors are expensive but they are self aligning,
and
> I've seen then for under $3 on the Internet.
>
>  Although the PCI is tempting and cheap for the backplane, it's a bus that
> is designed for digital logic, all pins are tied to the same pins in all
> cards. Prototype cards tend to be large and expensive.
>
>  A brief blurb on Eurocards;
>
>  < http://www.yotor.org/wiki/en/eu/Eurocard.htm >
>
>  Cheap prototype boards are available for $10 or less, a very important
> point, $50 to $60 for a PCI card is very expensive, maybe I'm too cheap,
but
> the blank board should not cost more than the components.
>  < http://www.sbszoo.com/ve6sbs/sale/cct-brds.htm >
>
>  Here are some available at Mouse;
>  <
>
http://www.mouser.com/index.cfm?handler=data.getPcodes&pcode=BPS%2BPrototype
%2BBoards&pcodenumber=85400
> >
>
>  Sample enclosure, can be home made from aluminum extrusions.
>  < http://www.busboard.net/bps-enc.htm >
>
>
>
>  At 03:34 AM 1/2/2006, Leon Heller wrote:
>
> ----- Original Message -----
>
> From: Eric Ellison
>
> To: 'Xylo-SDR Discussion'
>
> Sent: Monday, January 02, 2006 5:17 AM
>
> Subject: [Xylo-SDR] Some design thoughts requested
>
> Folks
>
>
>
> Even since the PIC 4550 days I have been thinking on how we might conduct
> experiments as well as have a reasonable environment for addingon to
the
> project. The obvious answer is a buss of some sort. I have looked at
> everything from Simm riser boards to ISA buss stuff. PCI risers might be
the
> way to go since they are inexpensive ($15) for 3 slot extenders. Also in
an
> end product they fit into the L-brackets of a computer case, or 2U mounts.
> They have assignedpower busswe can use, fairly inexpensive
prototyping
> boards. ($50 - $60), are four layer and designed to minimize intra trace
> noise. The buss wouldnt be used for PCI, however it would allow power,
(on
> designated standards based lines), intra board connections, and FPGA,
> I2C,signals etc.
>
>
>
> PCI seems to be a little largefor what we are proposing, and the
product
> boards would cost more to produce, however, with an established buss we
> could put a radio on one card, FPGA on another Audio on another etc.
>
>
>
> $15 Board amongst others:
>
>
>
>
>
> http://www.plinkusa.net/riser.htm
>
>
>
>
>
>
>
>
>
> Am I off the wall here?
>
>
>
> That's the sort of thing I was thinking of doing. I used to work for Racal
> and they used to build their military radios from separate screened
plug-in
> modules on a backplane.
>
>
>
>  I favour DIN41612 connectors for this sort of thing. They are expensive,
> but very reliable, and have pins on 0.1" centres. They can even accomodate
> co-axial connectors. They are more commonly used in Europe than the USA,
but
> you can get them over there without any problems.
>
>
>
>  73, Leon
>
>  --
>  Leon Heller, G1HSM
>  leon.heller@bulldoghome.com
>  http://www.geocities.com/leon_heller
>  _______________________________________________
>  Xylo-SDR mailing list
>  To post msg: Xylo-SDR@ae5k.us
>  Subscription help:
> http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
>  Xylo-SDR web page: http://xylo-sdr.ae5k.us
>  Forum pages: http://www.hamsdr.com/hamsdrforum/
>
>
>  Cecil Bayona
>  KD5NWA
>  www.qrpradio.com
>
>  "I fail to see why doing the same thing over and over and getting the
same
> results every time is insanity: I've almost proved it isn't; only a few
more
> tests now and I'm sure results will differ this time ... "
> _______________________________________________
> Xylo-SDR mailing list
> To post msg: Xylo-SDR@ae5k.us
> Subscription help:
> http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
> Xylo-SDR web page: http://xylo-sdr.ae5k.us
> Forum pages: http://www.hamsdr.com/hamsdrforum/
>
>
_______________________________________________
Xylo-SDR mailing list
To post msg: Xylo-SDR@ae5k.us
Subscription help: http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
Xylo-SDR web page: http://xylo-sdr.ae5k.us
Forum pages: http://www.hamsdr.com/hamsdrforum/

_______________________________________________
Xylo-SDR mailing list
To post msg: Xylo-SDR@ae5k.us
Subscription help: http://lists.ae5k.us/listinfo.cgi/xylo-sdr-ae5k.us
Xylo-SDR web page: http://xylo-sdr.ae5k.us
Forum pages: http://www.hamsdr.com/hamsdrforum/



Cecil Bayona
KD5NWA
www.qrpradio.com
"I fail to see why doing the same thing over and over and getting the same results every time is insanity: I've almost proved it isn't; only a few more tests now and I'm sure results will differ this time ... "