Attempting to use D13 as spindle on/off

Hey folks hoping someone might have a solution for this issue. I used the info from this post Router on/off and speed control with SuperPID and cncjs
to modify grbl v1.1 and upload it to my CM 2.4e board. D13 now boots at +5v, and goes to zero with m3 or m4 commands (usable). Any ideas on how to invert that behavior?

However, upon connecting Carbide Motion 635 says “Unsupported or invalid g-code command found in block” *edit: turns out CM uses M56, no errors after enabling that.

Edit: Something must have changed across grbl and/or board versions from the post I used for directions. Turns out DO NOT enable invert_spindle.


Are you trying to control the spindle speed or just on/off?

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I uncommented that per the instructions from another post. It seemed to be required to use spindle on/off instead of direction. The behavior is not what I would expect, +5v (enabled) when spindle is off, but 0v when M3/M4 given.

I think that’s what inverting it is supposed to do.

Inverts the spindle enable pin from low-disabled/high-enabled to low-enabled/high-disabled.

Indeed that is exactly what it does. What I get for believing everything off the internet! Working as desired now, well almost. It seems taping the PWM signal for the VFD makes the bit-runner not work until 12000rpm, so I will need to setup a power relay for my vacuum. Minor inconvenience.

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