Implementation of a CANbus interface for the Detector Control System in the ALICE ITS Upgrade

For the Upgrade of the ALICE Experiment in Long Shutdown 2, a new Inner Tracking System (ITS) is being commissioned, based on the ALPIDE Monolitihic Active Pixel Sensor (MAPS) chip.Data readout from the ALPIDE chips is performed by 192 Readout Units (RU), which are also responsible for trigger distribution, detector monitoring and configuration, and control of the sensor chips. The monitoring and control of the experiment is performed by the Detector Control System (DCS), which communicates to each RU through the same optical GBT-Versatile link used for slow-control operations. A Controller Area Network (CAN bus) interface is provided as a supplementary control path, and this paper will discuss the implementation of this interface.