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Updated: 20.2.2002

aOS - a RTOS for AVR

I have gathered here information about my aOS project. I'll try to keep these pages up to date as something new and revolutionary comes up ;-)

Also feel free to ask any question about aOS.

Anssi Ylätalo <anssi.ylatalo@upm-kymmene.com>

Latest version: 0.01, is available here. The source code is also included in documentation.

Change log:

ToDo:

• Proper interrupt handling from aOS point of view.
• Embed the uIP to aOS.
• Develop IO-mechanism: open(), close(), read(), write().

Documentation: Version 0.01 available in HTML-format and M$ Word 2000 DOC-format.

Questions and answers:

Q1: What is aOS?

A1: aOS is an implementation of real time operating system for AVR micro controllers written mostly in C.

Q2: What is the licensing policy?

A2: aOS is distributed under GNU Public License, GPL.

Q3: What are hardware requirements to run aOS?

A3: At the moment approx. 5 KBs program memory, >2.5 KBs RAM. RAM usage depends on stack sizes and how many tasks, semaphores or mailboxes are used.

Q4: On what hardware aOS is developed?

A4: aOS is developed on Atmel's STK300 with ATMega103L.

Q5: Which compiler is used?

A5: I have used CodeVision AVR C-compiler with integrated IDE.

Q6: Is aOS pre-emptive?

A6: Yes, any higher priority task which comes runnable will interrupt the current task.

Q7: What is scheduling policy in aOS?

A7: aOS uses static priorities, no round-robin. Highest priority runnable task will always go to CPU and will stay there until it suspends itself or higher priority task comes runnable.

Q8: Will aOS be deveploped further?

A9: Definitively yes. I'll do development in my own pace but everyone is allowed to make the development on his/hers own.

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