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artem
Joined: 22 May 2003
Posts: 1638
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Location: Turan
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 18 Jul 2003 12:46 ROBIN ROUND IMPLEMENTED RTOS |
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Does anyone knows the free RTOS for the AVR ATMEGA 128 which implements Robin round type of scheduling (If I am not wrong - Implicite task scheduling based on quantum time slice and task priority )
Rtos's I knwo do not implement that :
MuCOS and NUT/OS
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Ace-X
Joined: 25 Jan 2002
Posts: 594
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| 18 Jul 2003 22:10 |
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Round-robin is a scheduling strategy without priority or in others words where every task (process, device etc.) has the same chances to get access to resource.
May be you meant cooperative RTOS? This type of RTOS has implicit task scheduling.
Check this article:
http://www.embedded.com/2000/0009/0009feat4.htm
Maybe functionality of this OS will be enough for your task.
Ace-X.
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artem
Joined: 22 May 2003
Posts: 1638
Helped: 90
Location: Turan
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| 21 Jul 2003 12:17 |
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Hi
No I mean Round-robin scheduling .
The reason is I need to perform invisible rescehduling without invoking something like OS time delay fiunctions in code , because of
mcu I designing will execute 4-5 tasks running at the same pri , so I would to prefer OS to reschedule them on the quantum based timeslice instead of using explicit OS commands .
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Ace-X
Joined: 25 Jan 2002
Posts: 594
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| 21 Jul 2003 23:24 |
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Then any preemptive RTOS will satisfy your needs. It switches tasks transparently. Just assign the same priorities for every task in the system.
Ace-X.
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artem
Joined: 22 May 2003
Posts: 1638
Helped: 90
Location: Turan
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| 22 Jul 2003 11:19 |
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It is not that way for all OS . Let say I have analysed the NUT/OS and MuCOS
for NUT/OS it is possible to define the threads for the same pri but RTOS does not switch context - thread should deal with that . MuCOS even does not permit to define tasks with the same pri , and context switch for the low pri tasks will be done when high pri gives up control of CPU
or via semaphore , mutex queue or direct scheduler call or time delay - this is explcit task controlled context switch for tasks with same pri or to task with lower pri .
I had a look to the MuCOS forum aty yahoo , and one guy implemented wrapper above kernel which switches tasks one by one without explciti call to kernel . But this solution is not perfect as execution time is not determinsitic (up to some extend of course) and execution time slice for the task (quantum) is not adjusted based on task priority .
I would like to have scheduler similar to the Windows or Linux based .
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Lighting_D
Joined: 09 Nov 2001
Posts: 11
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| 22 Jul 2003 19:22 |
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| What about AVRX?
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petrick
Joined: 16 Sep 2003
Posts: 3
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| 22 Sep 2003 16:11 perpetual question |
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[quote="artem"]It is not that way for all OS . Let say I have analysed the NUT/OS and MuCOS
for NUT/OS .
I'm try to choose RTOS for every day use on AVR mcu. So what is NUT/OS - what is your opinion about it and where can I find source and description (if last RTOS cost that)
Yours sincerely. Petrick Andrew.
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artem
Joined: 22 May 2003
Posts: 1638
Helped: 90
Location: Turan
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| 22 Sep 2003 16:20 |
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The ethernut project is hosted on http://ethernut.de/en/index.html
schematics and software is free , Implements Ethernet ,
TCP/IP ...
avrfreaks has also list of RTOS working on AVR atmel
MuCOS is posted here and has port for AVR , but royality is not free
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C-Man
Joined: 19 Jul 2001
Posts: 1303
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| 22 Sep 2003 17:00 Re: ROBIN ROUND IMPLEMENTED RTOS |
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Also try your luck here:
hxxp://www.elektroda.pl/eboard/viewtopic.php?t=36952&highlight=tiny+rtos
best regards
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