CNC Mini Lathe school Project Synchronise spindle

[Remustgx]

Hi Folks, I am a technical guy from a school and we have a projet to make a mini destop lathe. I buy a SK3 for that and its working. BUT, one of the result is to be able to make a thread with the syncronize spindle. I can't tcheck to activate the option in the web builder. somebody can help me to build a code or how to be able to tcheck that feature? We Plan to buils 9 of them!

[terjeio]

You have two options with the SKR3 - either pins for the spindle encoder has to be added to the board map or you have to use a stepper as the spindle motor. The pin requirement is quite strict for one of the pins since it has to be "wired" as a clock input to a timer, using a stepper motor for the spindle is work in progress - it may or may not work.
@dresco knows the SKR3 board better than me, and I do not know if he has looked into supporting spindle sync for the H7 driver yet.

[dresco]

@dresco knows the SKR3 board better than me, and I do not know if he has looked into supporting spindle sync for the H7 driver yet.

I have attempted to, is but only lighted tested. I added spindle encoder inputs on my prototype board, but have only bench tested the code with a stepper spindle coupled to an encoder.

The H7 driver currently uses timer 3 for the spindle pulse input (and timer 2 for spindle index). I added support for anther external clock mode for more input options (and could also extend that to add TI1FP2).

fwiw I've also routed the A/B pulse inputs on my board to support quadrature encoder usage if that's an option in the future?

From a quick look at the SKR3 schematic, there aren't many options for suitable timer 3 inputs. Could potentially remap PA6 or PA7 on EXP2, which are currently used as interrupt capable control inputs. Looks like there some suitable pins wired to EXP1 that don't already have external interrupts assigned..