Re: New project...PCI based servo control board

[Jon Elson <elson-at-pico-systems.com>]

Craig Edwards wrote:

>As you probably know, the PCI bus (and associated drivers) are fairly
>complex, at least if one wants to do a full implementation.  Even 32 bit,
>33MHz target only VHDL code for a FPGA instantiation is pretty pricey, but
>I'm working on some options.  If we can afford a large enough FPGA, there
>will be plenty of room for stepper pulse generators and GP I/O.  As you
>pointed out, there a large number of trade offs to be made with regard to
>how many features we try to include on single board, but that's the fun of a
>project like this.  I'm not very familiar with Jon Elson's designs, but I'll
>have a look at them.  I think it's fair to say I'm pretty firmly in the
>"single board" camp, as I really want a solution that is tightly coupled to
>the motherboard. But having said that.. I guess we could consider "daughter"
>cards....:)
>  
>
Well, I guess I just don't understand.  I spent at least 18 months 
designing my
set of servo boards that run on the parallel port, and the performance is
EXCELLENT.  You want 10 KHz servo update on 8 axes?  No problem!
Want to add a pendant with jog dials, joysticks, lighted buttons, etc.?
(Not that this has been designed yet, but it should be quite easy.)
How about an auto tool changer?  Just add more digital I/O cards.

Anyway, I have designed the boards, programmed the FPGAs and CPLDs,
written the interface software, etc.  But, nobody buys it!  And, yet,
people are STILL talking about doing it ALL over again!

If you want  to see what I've done, take a look at
http://jelinux.pico-systems.com/PPMC.html

Anyway, as I said, I just don't understand why everyone wants to keep
doing it over, and over, again!

Jon