RE: [CAD_CAM_EDM_DRO] Driving the parallel port in WindowXP

HI Kory,

Ah, the age-old problem!

Windows makes a mess of critical timing involving a port write. Just
setting some lines? 20ms (?) doesn't bother you? Just work from windows.
If, on the other hand, you're trying to generate stepper pulses at 20K (or
even several hundred PPS), then Windoz is out, and you'll need to use DOS.
Art and Machs get around this with a high-priority "kernel" driver.

SPECOSOFT.COM is reported to have some portio routines, but I couldn't get
to their site today for some reason.

Even with Linux, you will need a special core routine, or a special build,
if I'm not mistaken.

So DOS may be required!

OR, start revving up on USB, which is what many are doing. Then buffer your
data out, and let a PIC or USB device clock data changes out at their best
interrupt rate.

Alan KM6VV

> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of Kory Hamzeh
>
> I have a CNC application that I would like to write and I need to decide
> it if should be DOS based or Windows. I would like to write it in
> Windows because I want the UI to be graphical, but I do have concerns
> about driving the parallel port reliably and consistently (timing wise).
> Are there any API's, docs, or tricks for this? Another option would be
> Linux, which I have a lot of experience with, but I'm not certain now
> many machinists use Linux for CNC.
>
> Regards,
> Kory