On Mon, May 18, 2009 at 9:05 AM, Jan-Erik Soderholm <
jan-erik.soderholm@telia.com> wrote:

> Besides, even an RTOS can't do more than one thing "at once"...
>

Of course, you have one core anyway. But it could help you to think as
threads were running parallel. It is just a different abstraction to
interrupts or polling methods on a non rtos system.

Like an event driven rtos 'thinks' that a change on a pin is an event when a
process has to be triggered to run. On a cooperative rtos the thread waits
for the pin change and till the thread is suspended. On a preemptive you can
poll the pin without suspending the thread (and the entire mcu) -- all of
them are doing the same basically with different way of thinking (and of
course of different overhead on it). One could help to approach a specific
problem better, the other one fits worse/better to many other related
functions. But of course there is no rtos that makes you possible to write a
firmware that was impossible on the bare silicon.

Tamas
-- 
http://www.mcuhobby.com
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist