An event generator is a peripheral module having one or more event sources. There is generally a strong correlation between the available event sources and the available interrupt belonging to a peripheral module. An event generator is feeding all its event sources to the event routing system, and is not aware of which event source is being used by other modules.
A channel path can be either asynchronous or synchronous to the main clock. The mode must be selected based on the requirements of the application.
For ATtiny817, there are four asynchronous event channels (registers ASYNCCH0, ASYNCCH1, ASYNCCH2, ASYNCCH3) and two synchronous channels (registers SYNCCH0, SYNCCH1), which are used to configure the event source.
Only one trigger from an event generator peripheral can be routed on each channel, but multiple channels can use the same generator source. Multiple peripherals can use events from the same channel.