OSEK Event mechanism

 

qThe event mechanism

vis a means of synchronization

vis only provided for extended tasks

vinitiates state transitions of tasks to and from the waiting state.

 

qEvents are objects managed by the operating system.

vThey are not independent objects, but assigned to extended tasks.

vEach extended task has a definite number of events. This task is called the owner of these events.

vAn individual event is identified by its owner and its name (or mask).

 

qWhen activating an extended task, these events are cleared by the operating system.

qThe meaning of events is defined by the application, e.g. signallingof an expiring timer, the availability of a resource, the reception of a message, etc.

qThe receiver of an event is an extended task in any case.

vit is not possible for an interrupt service routine or a basic task to wait for an event.