Re: FPGA for PCI based servo control board

[Robin Szemeti <robin-at-rszemeti.demon.co.uk>]

Fine fine ... I'm just not convinced that the extra effort in finding them 
and a sutiable case, PSU etc, is worth the space saving over a conventional 
small case PC .. anyway .. each to there own.

I'm sure they'll do the job (whatver that might be ...) I'm just confused by 
the whole thread really. 

What it seems to boil down to is this: 

EMC works fine, but for high pulse rate applications its give the CPU a hard 
time, so offloading that to an external device would be a good plan. Jon has 
already done this with his external stepper driver boards and found the 
market to be in the region of 5 a year ho hum. The thrust of the new project 
seems to be to split Jon's board in half, move the FPGA inside the PC and 
leave the IO external to the PC ... this avoids the 'problem' of using the 
printer port to drive the external card, but adds interfacing to the PCI bus, 
and then providing a custom interface to the IO board. Ethernet has been 
suggested, and perhaps using another PC at the other end to handle the comms. 

Now, call me a silly old goat, but it seems to be adding a bunch of extra 
hardware, to solve a problem thats already been solved in a slightly 
different way.  I dont see its any different to Jon's existing board, except 
its going to be in 2 boards, with the added 'fun' of a custom interface 
between the two.  I'm not saying that it won't be a fun project, (heck, I'll 
most likely build one or two if it does come off) but I'm not sure its that 
much of a 'must have' right now as it seems we already have it and about 5 
people a year buy it ... 

I'll be watching with interest though ... a PCI pulse gen card with external 
IO does sound rather apealing for some odd reason ... 


On Friday 04 April 2003 22:02, Craig Edwards wrote:
> Robin,
>
> Not to belabor the point here, as I think it really doesn't matter...  but
> the VIA boards that I've used cost my firm around $81 USD, including a
> 800MHz C3 processor (admittedly wholesale).  I should have not said......
> "you won't beat the price"....as someone ALWAYS will...:)   But at least in
> the US, there is no significant price penalty for this format. Yes I think
> you could  source an ATX MB with a C3 for SLIGHTLY less, but not much.
> Using a simple price check bot (my favorite is http://www.pricewatch.com./)
> I was able to turn up lots of retail places (in the US) the sell the same
> board for around $90 USD. One example... was
> http://www.essencompu.com/nupplysingar.asp?ID=3448  (never used them...so
> please don't treat this as an endorsement)
>
> As far as footprint is concerned, the only reason I thought small might of
> interest to some is because they are interested in packaging the MB with
> breakout board and drives inside of a single enclosure.  The smaller
> outline makes for easier integration, especially if you want to package it
> all up in a NEMA rated box.
>
> No doubt your experiences / needs / (and sourcing options....) differ from
> mine....always a problem on global lists such as this.
>
> Craig
>
> -----Original Message-----
> From: emc-at-nist.gov [emc-at-nist.gov] On Behalf Of Robin Szemeti
> Sent: Friday, April 04, 2003 12:55 PM
> To: Multiple recipients of list
> Subject: Re: FPGA for PCI based servo control board
>
> On Friday 04 April 2003 17:59, Craig Edwards wrote:
> > BTW, I've used those mini-ITX boards, it's a great format.... And no
> > you won't beat the price....:)
>
> Then you need to research your prices more carefully.
>
> from linitx.com
>
> Mini ITX case 64 GBP (95 USD) ...
> Via EPA 8000 mini-itx mobo, 1 Ghz  128GBP (190) USD)
>
> I can get comaprable items at HALF that price in standard ATX format ..
> whats
> the big deal about making it small?  .. sorry, but the logic has escaped me
> somewhere along the line ..
>
> remind me again .. ther reason we need to spend more money on buying a PC
> in
>
> a smaller-than-standard footprint is ..... ???  Sure .. theyre small .. but
> why did we need them to be small again? and why is the smallness worht the
> extra money over a standard case/mobo again?
>
> My workshop is 15m by 10m ... the day I dont have room for a standard PC
> case
> is the day I get a bigger workshop.

-- 
Robin Szemeti