Ok now I understand !
What kind of stepstick should I use for the LowRider axis ? TMC2209 too ?
Instead of using a stepstick with an external adapter, could I config firmware to use pins for enable, step and direction on an MOD socket for the OTK-3 knife ? That way I could design a special MOD including the DB15-SUB plug for it…
So I could use the stepstick sockets for XYZ axis, and a special MOD pcb for OTK-3 plug.