The above usage is correct(2.1*) with asterisk being your modifier, same way you would pull a pin high(^) or low(v), set to open drain(o) or invert(!).
Are you saying I should’ve used alpha_step_pin 2.0* instead of alpha_step_pin 2.0!?
I’m a little confused by your comment.
He’s saying that the modifier (punctuation mark, of which there are several) goes after the pin assignment number. You have 2.0! correct in your example. Smoothie can do other things, like 2.0o and 2.0!o, which should be outside the scope of what you need.
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@raykholo - Ok, cool. So now I guess the question is why did inverting the step pin not really change anything?
Is there a setting in Smoo for the duration of a step pulse? I wonder if extending that might help?
http://smoothieware.org/configuration-options
http://smoothieware.org/motion-control
microseconds_per_step_pulse ?
This is what I’ve got…
# Stepper module configuration
microseconds_per_step_pulse 2 # Duration of step pulses to stepper drivers, in microseconds
base_stepping_frequency 100000 # Base frequency for stepping
That’s unchanged from the base C3D config which would I assume be for the built in drivers whereas I’m using external DM542 drivers. No idea what the means for what, if at all, this value should be changed to…
Try 4 or 5 - Shouldn’t hurt anything.
Those are default Smoo values. Never changed them for C3D specific stuff.
Cool, will give it a shot.
Ok @LightBurn and @raykholo, in an effort to science the #$%@ out of this, I tried 4 new tests with varying configurations:
MSPP label is the microseconds_per_step_pulse value and inverted *_step_pin for both X and Y is noted for each.
Last, the measurement labeled at the bottom of each is the measured gap between the outline and the fill lines at the bottom of each. Each was of course run with identical LightBurn config. Only change was Smoo config.
Note, each triangle is 30mm on bottom and left sides
5us pulse and inverted is definitely the winner here at 2.3mm out of spec. Which is weird as without the inverted pins, the 2us pulse was the winner, though barely.
What do you think?
I’m way out of my depth here, although I did enjoy your phrasing:
@Jfong Jim might know more about this niche topic.
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The dm542 drive is sold under different variations which is a clone of the original Leadshine DM542. I can’t tell if you have a original leadshine version or a clone. Most of the clones don’t have all the features of the leadshine nor do they use the higher spec optocouplers and other parts. As with clone drivers, some may just not work very well.
That said, the original leadshine version requires a 2.5microsecond step pulse width and have jumper selectable rising and falling edge step pulse. It can be either active low or active high.
The clones don’t have a jumper selectable edge and I think most are active high. So step pulse on the rising edge.
Assuming a lower grade optocoupler are used on a clone drive, 5 microsecond step pulse width should be OK. I probably wouldn’t use lower than that.
Again you may just have a faulty driver and swapping out with a known good one is only way to see if your issue goes away.
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@Jfong - Sounds like mine are the clone then 
I got these -> https://www.amazon.com/gp/product/B07LD6XN5G/
No jumpers for rising vs falling or anything that I can see on them.
@raykholo is there a reason you recommended the DM542 over the one you sell via C3D?
I’m not totally against replacing the drivers, just need to know what’s the right thing to get.
Any thoughts on the driver @LightBurn, @raykholo, @Jfong? Gonna have time to mess around with it some more next week… I’ll pretty much order whatever you tell me to 
Pizza and Beer!
Way ahead of you, Rick 
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I believe Openbuilds uses and possibly sells the DM542 so I figured it would be a good model. I had seen it used in a lot of builds.
I picked up some TB6600 drivers to play with. Will let you know if the issue goes away.
(╯°□°)╯︵ ┻━┻
Boom. It works with TB6600 Drivers. First time.
The only thing that is a bit odd is that when I swapped the drivers I had to go into the smoothie config and invert the X and Y directions compared to what I had with the DM542. Mostly I say this is odd because the stepper connections between the two were identical in terms of A-/A+ / B-/B+, and I triple checked the ena, pulse, and dir connections (which were different). But whatever, 2 second fix in the config.
I’d love to understand why but I’ll settle for it working 
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