RE: [CAD_CAM_EDM_DRO] Re: Lost Steps => time for microprocessors!

> Ron Ginger wrote:
>
> > Ah well, we dont disagree that a dedicated box of electronics should
> > do
> > the hard real time stuff. If its a microprocessor or a gate array, the
> >
> > effect is a special box of hardware.
> >
> > I assume your box needs to be told how many steps to move, and how
> > fast
> > to make them. How do you handle the acceleration, let the PC program
> > it
> > in a series of short moves until it reaches speed?
>
> No, it is essentially only told velocity and direction (and an on/off
> bit, too.)
> That is all it needs. The decoupling of the velocity output from the
> computer
> needs a position counter to be added, but I am already working on that.
>
> > If your box has a nice clean interfce so I can poke values to it by a
> > simple driver, or even the BASIC equivalents of PEEK and POKE, then it
> >
> > shuold satisfy my needs jsut fine.
>
> Well, you could generally do that. It will use the EPP signals on the
> parallel
> port. There would be 3 addresses per counter x 4 channels, so that
> would
> come out to be 12 bytes to load. Those could be sent with a burst of
> DataStrobes in less than 24 uS using the EPP protocol. I've done
> stuff like this for the quad DAC board, it is just a couple of lines of
> code
> in Turbo Pascal (my language of choice for this sort of stuff).
> Of course, I'll be writing a driver (real time module) for EMC under
> RT-Linux.
>
> > I am very anxious to hear the specs of your box and know when it will
> > be
> > real.
>
> I have to build and test the encoder counter board, next. The DAC is
> done, and
> the biggest hurdle was getting the fast EPP transfer modes to work, by
> far.
> But, now I know how to do that! The emcoder counter is a pretty complex
>
> device, about 4 pages of VERY tight schematics on one chip. It will
> probably need a little tinkering to get it to run just right. Anyway,
> the
> program for the FPGA is written and compiled, and the board is etched
> and drilled.
> So, it will take a couple of weeks to get it fully operational. Then, I
> have taken
> on a project to make the 'wonderboard', a parallel-port opto-isolated
> input and
> power output board. That will take a couple of weeks. Then, I can
> look into the timing generator. Since I'm going to have boards made for
> the
> encoder counter, I can probably hack one of those to convert it to a
> timing generator prototype board. (Actually, it might be possible to
> just
> put a different program in the chip, leave out the differential
> converters
> and use the board as is!)
>
> Jon