Does the Direction act as a pulse for each step? or does it change state for reversals of motion direction only, ie. steady state for duration of move in that direction?
Dir is a state, not a pulse.
My steps are set to "Low Active" in the Motor Outputs.
Is that what Gecko recommend? if so, OK.
Do confirm with the CRO that the negative going pulse on the Step line is narrow, with a wider Hi state. This is illustrated in the Mach3Mill doco. Check you can vary the width.
I would like setup instruction on using an O'scope as I do have a BK Precision 1530 30mhz scope. If it could be hooked up to see the timing differences between step and direction it would be nice. It is a simple dual trace scope, not a storage type.
Um ... putting into words what I do automatically ... Um! Interesting challenge!
OK. First, disconnect everything from the PP. Bare PC.
Hang channel 1 on Dir and channel 2 on Step. If you have a separate trigger channel hang that on - um, try Step for now. Otherwise trigger off channel 2 for now.
Program the machine to do about 10 steps forward and 10 steps backwards, for many cycles. Adjust the CRO so you can see the Step pulses. The sweep rate won't be very high. The Dir channel will flip up and down. That gets the CRO going.
Now trigger off the Dir channel instead. You should be able to see the slow square wave on the Dir channel and the fast Step pulses on the other channel. Get this going. Now you will be able to see 'ground truth'.
Look at the timing between the Dir transition and the Step pulse downwards (leading edge) transition. What you do NOT want is for the Dir and Step transitions to be too close - that can confuse the Geckos. Also look at how fast the two signals go from Hi to Lo and Lo to Hi: the transition times. Record all these things - paper and pencil & sketches are fine.
Repeat all this with the BoB on the PP, looking at the output of the BoB. What do the pulses look like, and what is the timing like.
Repeat all this with other elements in the chain, up t5o the point of having a running motor. See if there is a shift in the timing between Dir and Step, or if the transitions times change, when some part is put into the chain.
You noted 'stuttering' at the start of a cycle - when Dir changes. This is where I would focus. You want to see what is going on here.
Hypothesis: you are getting a step pulse, or at least an edge of the Step pulse, or part of a Step pulse,
while the Dir signal is changing state. This will confuse the hell out of the Geckos and most certainly cause 'stuttering' and screw up the movement of the motors.
Of course, if the stuttering has disappeared but the drift persists .. um ...
Cheers
Roger