embedlets-developer

[Andrzej J. T. <an...@ch...>]

Brill:

> Is the timer service you have set up emulating a hardware timer, or is it a
> service in general? (I think a "service in general" would be useful).

It is a general service and is not intended to emulate or otherwise replace 
hardware-based timers.  Due to the design of the service, and the facilities 
provided by the underlying Java implementations, the Timer service can only 
provide an "approximation" of the timer duration that a component (eg. 
Embedlet) developer may request.  So a 100 ms. repetitive timer may fire at 
150 ms, 120 ms, 100ms etc. The timer service should be used for situations 
where the absolute timer interval is not overly critical. 

Hardware (and interrupt based timers) are typically used when the timing 
requrirements are more stringent.

For example, the timer service might be more than sufficient for an Embedlet 
to poll the value of a sensor on a periodic basis, but would not be a good 
choice for the generation of a pulse stream that had a very regular high-
speed frequency.

Does that help?

Andrzej Jan Taramina
Chaeron Corporation: Enterprise System Solutions
http://www.chaeron.com