To control the stepper motor a PCB has been made in kiCAD. it is a FTDI circuit.
The head is equipped with an Arduino Nano, connected to the HDB in order to receive serial commands from the Totumduino controller inside the FABtotum via the flex cable.
If it sound complex it’s because it is, and S&I Engineering went the extra lenght in implementing all the communication protocols .
As a side note it is also important to notice that other options to control motors with less components exists, like using the 5th axis native port (on the bed connection board inside the FABtotum Core) or using the newest FABlin feature to send steps/dir directly via software and the HDK board pins (SCL=Feeder Step , I2C SDA=Feeder Dir, SERVO +5v =Feeder Enable).
This FTDI circuit PCB has also been milled with FABtotum using FlatCAM to generate the gcode and the Milling Head V2 with a V-Carve engraving bit, wich makes everything even more impressive.
Back to the serial comunication, the Arduino sketch has been developed to act like an intermediary, executing stepping controls directly from the head to the attached stepper motor.
The *.ino file can be opened in the Arduino IDE, can be flashed on the Arduino Nano, and is open source so can be studied and modified to fit custom needs.