Re: freqmod - step pulse timing

["Joel Jacobs" <jj-at-netexp.net>]

----- Original Message -----
From: "Joel Jacobs" <jj-at-netexp.net>
To: "Multiple recipients of list" <emc-at-nist.gov>
Sent: Monday, March 20, 2000 5:30 PM
Subject: freqmod - step pulse timing


>
> Could someone tell me please, does EMC expect the stepper controller to
step
> on the rising edge or falling edge of the step pulse?  Is Direction valid
> for a complete +/- or -/+ step pulse cycle?  What is the minimum step
pulse
> width?  How long after a step can direction be assumed to be valid?

Ok, I think I got this figured out last night let me know if I'm wrong.  It
seems that the stepper controller should step on the rising edge of the step
pulse and that the direction signal will be valid for at least 1 X PERIOD.

I found a bug in my controller program that at worst case is giving about
15us latency to the step interrupt.  If I set the PERIOD back up to 16us the
problem goes away.  I developed my controller using another software that
outputted 50% duty cycle step pulses so even at 10khz the step was 50us
long.

Joel