Hi:
>>"Art’s ‘Darwin’, parallel port driver, performed beautifully during the tests with no faults or bugs to report. It is very easy to set-up and the motion produced is just so smooth it is difficult to describe the difference from Mach3."
My experience is VERY different which makes me think I am doing some rather stupid things. I am using Darwin 1.08 with Mach4 1888
Goes to show experiences do vary. Could be machine, could be something else..time and testing will tell. Doesnt make you any dumber than I.. Im sure testing will show why things are screwy.. I havent had any limitations even up to 70,000 pulse frequency..BUT Im using servo's which can smooth timing discrepancies out of a stream. Its very possible that some problem or
another is creating trouble. Tweaky is the second to have grinding noise above a certain value.. Its something Im hoping time
and use will point to. It may be pulse width as one person pointed out. I only pulse at the default of 1us or so on the step, allowing the minimum time of pp port register changes to control the time. Im m3 I added up to 3-4 us to make the pulse
longer.. I may have to try that to see if it helps. (Tweaky: did you have to add time before to the pulse widths?)
>>Firstly I abandoned any idea of using Metric. The results just confused the hell out of me.
I used only metric, but I found any switch between inch and mm caused huge trouble for me, first you have to restart the program and something about the switch junked many things.. until latest version 1900 which seemed to fix that up for me.
>>For the life of me I could not get B axis (motor 4) selected as slave to Y axis. Had to settle for A axis (motor 3) Just could not figure how to get it to allow me to select B as slave.
In M4 no motor actually owns an axis. Your "B" axis is simply motor 3. So youd map motor 3 to B axis in M4 and slave it. But Ive done no slaving tests so I cant confirm slaving works.
>>Maybe that is a built in limitation of hobby version. That would be a shame as I have one slaved axis and also a 4th axis (rotary). That would blow Mach4 out of the water for me as a future option.
Darwin only handles 4 axis at the moment, I havent turned on the others, Ill list to do so, no reason for them to be off anymore..
>>Dual axis homing I have not worked out yet. Master and slave work well together up until I reference that axis. Then they try to move in different directions.
Probably has to do with the mapping, the homing can handle slaved axis, interesting that they move in different directions... ID have thought theyd home the same way they move, in reverse to each other. (Listed for checking)..
>>However all that is small potatoes compared with the smoothness of operation (or lack of it) compared with Mach3.
>>25000 kernal speed. Good driver test graphic. Time in interrupt approx 7 micro seconds (is this my problem?)
Thats low compared to M3, and likely due to the decreased pulse width. Did your M3 have pulse width setting higher than default? Ill add a setting for that to see how stretching the pulse might help in smoothness for you. Mine is very smooth as was tweakies, but even Tweakie has roughness above a set number...that makes me thing pulse width..
>>Any ideas what silly mistake I have made?
None.

, you tested and reported, Im gratefull. I will add in a pulse stretch by making all steps take a 1us wait to make them longer, we'll see if that helps, and Ill check the homing to see why a slave might home in the reverse direction.. ( Thats ahandy report..). Ill also turn on the other two axis so 6 motors can work..
Thx
Art
Greolt