Arduino Forum

Using Arduino => Programming Questions => Topic started by: fiddler on Jun 01, 2013, 09:21 pm

Title: clock-driven round robin scheduler
Post by: fiddler on Jun 01, 2013, 09:21 pm
Hi

Im looking for a clock-driven round robin scheduler for the Arduino
Just need an task overrun indicator

I have had look but they all appear to be or close fully blown RTOS's

Any suggestions

Ta
Title: Re: clock-driven round robin scheduler
Post by: CrossRoads on Jun 01, 2013, 10:26 pm
Write your own?
I've only written for a specific project.
Do things like capture
currentTime = millis();
and check if the currentTime is >= to the next time I want some to happen.
Can do that for as many tasks as you want to run.

If you want more, probably have better luck asking in the software forum, get a real software engineer involved.
Title: Re: clock-driven round robin scheduler
Post by: el_supremo on Jun 01, 2013, 11:53 pm
What sort of tasks are you going to be running that requires a round robin scheduler?

Pete
Title: Re: clock-driven round robin scheduler
Post by: TanHadron on Jun 02, 2013, 02:38 am
By clock driven, do you mean preemptive?  Which version of Arduino are you looking at?
Title: Re: clock-driven round robin scheduler
Post by: fiddler on Jun 02, 2013, 10:25 am
I just want to make sure that no tasks take longer than a set time and that I get back to some tasks within a specified time.

If the task overrun in time, I just need to set a semaphore so I know. Possible do some controlled shutdown or something.

Would be handy to know which task overflows, but at this point is properly not necessary.

I don't need priority, dynamic scheduling or anything like that.

Round Robin schedulers are predictable.
Trying to eliminate use of interrupts to get predictability

Was sure this most have been done numerous times, but maybe not released as free/w

Have been watching the TTE systems videos on youtube and like his approach, predictability :-)
http://www.youtube.com/watch?v=Q28ERQ2XhmA


Title: Re: clock-driven round robin scheduler
Post by: wildbill on Jun 02, 2013, 12:43 pm
Search for posts by Morris Dovey. IIRC, he posted details of his home grown task scheduler.