This firmware seems to 'stutter'. Ie. all steppers will stop for a few milliseconds every few seconds. If travelling fast, sometimes that causes layer shift, especially on the Y (bed) axis. It degrades print quality a little, and seems to be the reason that nobody else has managed to make linear advance work well on this model.
Stuttering happens much worse with linear advance enabled, but is still present slightly with it disabled.
It happens when printing from SD and USB. It happens even in straight movements, so probably isn't something todo with buffering linear moves. It's especially noticeable when moving fast.
Looks like the most likely cause is some long running interrupt or similar. The added computation of linear advance might be exacerbating something missing a deadline somewhere.
Thats as far as I've got debugging it.
(Note that if testing with linear advance, you need to set M569 S0 E to disable stealthchop and avoid the extruder stepper stopping mid print)
This firmware seems to 'stutter'. Ie. all steppers will stop for a few milliseconds every few seconds. If travelling fast, sometimes that causes layer shift, especially on the Y (bed) axis. It degrades print quality a little, and seems to be the reason that nobody else has managed to make linear advance work well on this model.
Stuttering happens much worse with linear advance enabled, but is still present slightly with it disabled.
It happens when printing from SD and USB. It happens even in straight movements, so probably isn't something todo with buffering linear moves. It's especially noticeable when moving fast.
Looks like the most likely cause is some long running interrupt or similar. The added computation of linear advance might be exacerbating something missing a deadline somewhere.
Thats as far as I've got debugging it.
(Note that if testing with linear advance, you need to set
M569 S0 Eto disable stealthchop and avoid the extruder stepper stopping mid print)