Arduino is an open source prototyping platform for electronics. There is so much you can do with Arduino and the community is proof. In playing with Arduino I decided that it would be a great project to create a small multitasking library for use on AVR platforms, which includes Arduino.
A small introduction
avr-os is a library that provides a very basic rutime that enables your program to multitask.
The library uses pre-emptive multitasking to switch tasks and each task has its own stack that is restored when a task is resumed. An AVR timer is used to provide ticks and this interrupt is used to switch tasks.
Hello World, avr-os style
The following sketch is a basic example of how multitasking can be used in your Arduino sketches. This sketch has two tasks that continously print the task name and some information to the LCD.
It demonstrates how a task is started, how os_sleep can be used to sleep tasks, and the ability to use spinlocks.
The image below shows the sketch in action:
Using the OS
The following is the header for avr-os that demonstrates the features available:
Try it out
The code is available here and contributions are definitely welcome.