CNC on the Cheap** revisited**

Hi;
I thought I'd touch base about my cheapskate CNC toy I'm workin' on.
(see post #85589).
On the "command vue 111" that I originaly wrote here about, I'm sure
I've got the circut figured out. I traced the motor input traces
back to (thru) a small driver chip:SK #SDH 02 I've got the pinouts
figured out, the thing I lack (among many things) is knowing
how/where to introudce a 2 wire output (step/dir from my PC-running
Mach #2 mill) into a 4 wire input(at the drive chip). I realize that
the SK chip is a DRIVER not a controler. When I try to trace the
signal inputs to the chip, it all gets too confusing real fast. I'm
thinking I could rig up a simple circut to provide 4 wire input to
the driver and I'm home. Any feedback or suggestions?
A second unit is a similar story: dot Matrix printer, this one is
larger& has bigger motors. I forgot to take note of the Mfg. before
throwing all the plastic away. The driver on this one is SLA 7024M,
which I've had luck with before, using a Basic Stamp. I've actualy
scratched out the traces leading to the chip's input signals &
soldered wires in place. (still- 4 wire input req'd. only two from
Mach 2!!!)
One last thing(sorry to be so ling winded): I intend to keep
everything in its original config. EXCEPT the 4 wire signal to the
SLA 7024 chip, so the power supply, ref voltages, & other "stuff"
(technical jargon)will remain active. Do you'all see any probs with
this arrangement??
Thanks in advance!
Richard.
PS: I'm really getting into this Hackin'/reverse engineerin'/Mad
Scientist thing! Just need more data.