From the original Synthetos forum (2011–2025)
My point is, how is it a gcode issue if it will run everywhere but edge and master? But when all was done, the graphic on the tgFX screen proudly displayed a perfect picture but the wood under the spindle was like Congress.
Alas, it matters not because I'll be out of the game for a bit.
I realize this thread is very old but I'd like to add to it anyway in hopes of getting a reply.
Regarding the exposed signals on headers for the four motors, would it be possible to use "enable" to bypass, override, or work in combination with the existing code? I was hoping to add a key switch that would enable the motors when allowed. If the processor ties the enable to ground in order to assert enable but already has a pullup, is there any reason why I can't add another external pullup and the key switch without any processor code change? Also, does the existing code read the state of enable as well as write to it in order to see if the necessary state was reached?
Bump
Has anyone used the "enable" line with an external switch?
This doesn't appear to be a very active forum ... someone please prove me wrong
Forum - Not as active as some other related forums, such as Chilipeppr, Ox and others.
Your query about Keyswitch is a bit unclear to me - when you Say "I was hoping to add a key switch that would enable the motors when allowed.", Allowed by what? Do you mean the key switch?
Would you install one keyswitch per motor?
Is your objective to force motors ON, irrespective of logic (the tinyG state machine) or provide a lockout function, keeping Motors disabled unless keyswitch was in proper position?
The Step-Dir-Enable interface is intended to drive external steppers.
Enable is a logic output, active low.
I don't believe you can backdrive the Enable Ports, if that is your question.
I assume you have looked at the Schematics?
https://github.com/synthetos/TinyG/tree/master/hardware/v8schematics
The use of the key switch would enable/allow motion for all axis as an additional layer of safety. So yes, a lockout function. I did look at the schematics but didn't notice that the enable was an output. There may not be another way to do this with this board since there is no dedicated input.
Since all logic on the board is powered by Vmot and not USB power that doesn't appear to be an option either.
Looks like I may have to leave this feature out unless you or others have a suggestion.
Thanks for the reply!
I don't see a way to "lockout" the on-board stepper drivers with a mechanical switch.
As you note, interrupting Vmot would cause a tinyG reset.
You could use the $md command to disable all motors, but that is logical
The only other thing I can think of would be to use to use a DPDT relay on each motor output (for each coil pair). I doubt I'll do this now but maybe a feature suggestion would be to have a some configurable inputs for functions like this.
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