PicoOs

Overview

pico]OS is a highly configurable and very fast real time operating system. It targets a wide range of architectures, from the small 8 bit processors with very low memory till huge architectures like 32 bit processors with lots of memory.


Features

pico]OS is currently divided into two layer. The pico-layer (the core of the operating system) includes this features:

Scheduler:

two modes: standard priority based or round robin
preemptive multitasking
max. 64 tasks on 8 bit processors, max. 1024 tasks on 32 bit processors
round robin: max. 8 priority level on 8 bit processors, max. 32 priority level on 32 bit processors

Events:

the number of events is unlimited
semaphores
mutexes
flag events

Message Boxes:

one built in message box per task
unlimited box size, messages are collected
messages can be pointers or huge buffers

Timer:

autonomous running timer, the system timer interrupt is used as timebase
timer can work in one shot mode or in auto reload mode
when a timer expires, it triggers a semaphore event

Software Interrupts:

up to 256 simulated software interrupts on 8 bit processors
can be used to interface fast hardware interrupts outside the scope of pico]OS to the operating system

Miscellaneous:

atomic variables
blocking and nonblocking lists
debugging support allows access to internal structures


The optional nano-layer supports:

Bottom Halfs for interrupt service routines
Multitasking able console I/O
Multitasking able dynamic memory management
Standardized API for easier task creation
Named tasks, semaphores, mutexes and timer
CPU usage measurement