The UPDI is connected to the Event System (EVSYS) as described in the register Asynchronous Channel n Generator Selection.
The UPDI can generate the following output events:
This event is set on the UPDI clock for each detected positive edge in the SYNCH character, and it is not possible to disable this event from the UPDI. The recommended application for this event is system clock frequency measurement through the UPDI. Section System Clock Measurement with UPDI provides the details on how to set up the system for this operation.