Micriµm: µC/OS-II Real-Time Operating System Kernel Overview

Overview

µC/OS-II, the Real-Time Kernel, is a portable, ROMable, scalable, preemptive, real-time deterministic multitasking kernel for microprocessors, microcontrollers and DSPs. Offering unprecedented ease-of-use, µC/OS-II is delivered with complete source code and in-depth documentation. Most of µC/OS-II is written in highly portable ANSI C, with target processor specific code written in assembly language. Assembly language is kept to a minimum to make µC/OS-II easy to be ported to other processors. To date, µC/OS-II has been ported to over 40 different processor architectures, ranging from 8- to 64-bit CPUs. µC/OS-II can manage up to 250 application tasks and provides the services including: semaphores; event flags; mutual-exclusion semaphores that eliminate unbounded priority inversions; message mailboxes and queues; task, time and timer management, and more.

μC/OS-II’s footprint can be scaled (between 5 Kbytes to 24 Kbytes) to only contain the features required for a specific application. Depending on the processor, μC/OS-II can be reduced to as little as 2K bytes of code space and 300 bytes of data space (excluding stacks). The execution time for most services provided by μC/OS-II is both constant and deterministic; execution times do not depend on the number of tasks running in the application.

A validation suite has been developed for μC/OS-II and provides all the documentation necessary to prove that μC/OS-II is suitable for Safety Critical Systems common to Aviation and Medical products. Although this feature may not be applicable to your needs, it does prove that μC/OS-II is a very robust RTOS. μC/OS-II has been used in hundreds of products from companies all around the world. Specifically, μC/OS-II is currently implemented in a wide array of high level of safety-critical devices, including:

• Those certified for Avionics DO-178B
• Medical FDA pre-market notification (510(k)) and pre-market approval (PMA) devices
• SIL3/SIL4 IEC for transportation and nuclear systems, 99% compliant with the Motor Industry Software Reliability Association (MISRA-C:1998) C Coding Standards

Typical Applications:

• Avionics - used in the Mars Curiosity Rover!
• Medical Equipment/Devices
• Data Communications Equipment
• White Goods (Appliances)
• Mobile Phones, PDAs, MIDs
• Industrial Controls
• Consumer Electronics
• Automotive
• A wide range of other safety critical embedded applications

Key Features

• Preemptive multitasking real-time kernel with optional round robin scheduling
• Unprecedented ease-of-use combined with an extremely short learning curve enables rapid time-to-market advantage
• Runs on the largest number of processor architectures with ports easily downloaded
• Highly scalable (6K to 24K bytes code space, 1K+ bytes data space) I Max interrupt disable time: 200 clock cycles (typical configuration, ARM9, no wait states)
• Sufficiently robust to meet rigorous safety-critical system requirements
• Very Low Interrupt Disable Time
• Delivered with complete, clean, consistent, 100% ANSI C source code with in-depth documentation.
• Up to 254 application tasks (1 task per priority level), and unlimited number of kernel objects
• Timeouts on ‘pend’ calls to prevent deadlocks
• Mutual exclusion semaphores with built-in priority ceiling protocol to prevent priority inversions
• Provides a variety of useful services: event flags; message mailboxes; message queues; fixed-sized memory partitions, task management, time management
• Third party certifiable