Re: EMC question

> Yes, hardware can make a difference but it should not make to much

of a

> difference.

I really didn't think so. For one thing, I'm not actually using that
much hardware, as you'll see...


Now Via/Cyrix

> processors are the most common in my basement.

I accidentally burned my last one of those up a couple years ago. The
remaining recyclable machine has an AMD 200 in it, and that's what I'm
running lately.

I'm using a less than barebones circuit using the STM l297 stepper
controller IC. It has a pulse shaping front end. From what I have
seen going in and coming out, it is doing a fine job of handing the
received signal and generating 2 phase halfstep waveforms. The step
clock coming directly from the port and dumping straight into the 297
looks fast enough and clean. The entire high current power supply is
isolated except with a "loop free" reference to PC digital ground.
This topology may not be so good for actual multi-axis running in a
machine environment but I didn't want to have any ???? about my
optoisolator signal circuit on top of any other ???? that may have
popped up. That's mainly an excuse. Mostly, I didn't wanna build a
bunch of goodies until I got the basics working, because I'm lazy.

I wonder how it would

> sound to hook up a pair of speakers in place of the stepper motor.

Step

> pulses in stereo!

That's funny. I've been listening to stepper motors in different
machines for a maybe fifteen years, and though it never got to be
music, I could tell at a distance something was really wrong with the
drive signal my rig was generating before I got the scope on it. When
I did get the scope on it and saw the glitches were coming out of the
PC I was pretty sure I had a serious software problem.

I appreciate your sharing of experience. Most of what you wrote
supports my suspicions and help some routes of focus to check out.