I've been pondering the purchase of a CNC lathe/mill, but for cost reason=
s I'm=20
going to do this incrementally ... pick up the basic machine first, then =
add=20
on stepper motors and CNC capability later.  But I'm researching first...

Seems like there are multiple vendors that make CNC controllers and the b=
est=20
part is that they're all compatible (work with the same software, interfa=
ce=20
thru the parallel port, and control the same types of motors).

I'm thinking of making my own controller instead of spending $500-$800 fo=
r a=20
ready-made unit, but I'm evaluating if this can save me any money (I real=
ly=20
expect it would definitely be worth my time).

I found a bunch of general stepper-motor controller circuits thru google,=
 and=20
it seems that the L298 drivers are popular for this size stepper motors (=
Nema=20
23, generally 100-150 oz-in units).  Not sure if the motors are run unipo=
lar=20
or bipolar (I'm still figuring out what exactly that means) though.

I'd like to control this with a PIC.  The PIC and par-port side of things=
=20
should be easy, once I figure out what this interface protocol standard i=
s.

Any of you know what this parallel-port "standard" protocol is?  Got any =
good=20
circuits that do this already, to save me re-inventing the wheel?

Thanks,
-Neil.

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