Re: time for microprocessors!

Hi Jon,

Glad to hear you're so far along. Some comments/questions.

Alan


Jon Elson & Alan Marconett wrote:

>
> > Jon,
> >
> > Is the Spartan chip an FPGA? Or a BIG CPLD?
>
> It is a true FPGA, 5000 usable gates equivalent.
>
> > Perhaps you could supply a
> > reference source for parts, info and "compiler". Do we need to spend
> > gobs of money for the compiler, or is it freely available?
>
> Why would you want to recompile the part? Why can't you just get the
> PROM
> bitstream from me, or just by the prom from me?

That's fine, no intention of duplicating or competing with your
efforts. Just a way to evaluate the scale of such a task, and whether
it is something I would want to investigate (a step up from PIC's?).
Shucks, I might even learn enough to redesign the data acquisition
system for an embedded system we build here at work (I know, leave it to
the EE's). But that's what it's all about, learning.

>
> > Are any
> > available in DIP style packages, for prototyping?
>
> No, I am stuck using the SMALLEST Spartan, at 68 pins, because I don't
> want
> to get into 208-pin devices!

Looks like it may be hard to wirewrap! Do you go straight to PCB
layout? Ouch! But then, it's all a simple matter of programming! ;>)

>
> > I'll pester my son at
> > UCSD and see what gate array stuff he was doing. Would you want to
> > give
> > us a run-down on what is planned for the board and what it's goals
> > are?
> > if too early or not a good idea, I can understand.
>
> Well, I have already designed a 4-channel, 24-bit encoder counter, with
> fast-EPP
> interface all on one Spartan XCS10 part. It has logic for handling the
> index pulse
> and presetting the counters. It will take differential or single-ended
> encoders,
> with or without the index pulse.
>
> Using the same chip, I have come up with the idea of putting 4 24-bit
> recycling counters
> in a chip, with a similar interface. The computer would set the number
> of clock ticks
> to count before putting out a step pulse. The step pulses (and
> direction signal) would
> also be used to generate a 2-phase signal, which could be used to drive
> a phase
> input stepper driver, or to feed to the encoder counter for position
> feedback.
> Or, you could use a real encoder on the motor to keep track of position.
>
> Jon

How about acceleration tables, such that the steps generated would
follow an acceleration profile? How would endpoint correlation be
handled, for compound axis moves (if that's what you call all that, I
may not be using the correct terms)? Sounds like that would be tough!