Just a small update. The video shows the homing cycle. The commands are loaded from SD card.

Grbl runs on Core 1 and the UI with touch on Core 0. The G-EDM API provides easy access to the basic Grbl functions like jogging, homing, running files from SD card, pushing commands to the buffer or run realtime commands.

Jogging motions are canceled if the axis are jogged while it is already running a jog command and access to the touch motion controls and sd card is restricted while grbl is running. This is indicated by the gray color of the buttons.

Edit: Instead of creating a custom spindle I used the existing laser spindle class from GRBL. It works. PWM Frequency and Duty can be changed via touch inputs and the interface pushes the needed commands to the grbl command buffer. Enabling and disabling the spark generator works too.

Now it is time to implement the probing. The probing is not exactly what grbl expects and it will use a custom probing routine.