µC/OS-II

µC/OS-II is a portable, ROMable, scalable, preemptive real-time, multitasking kernel for microprocessors and microcontrollers. µC/OS-II can manage up to 63 application tasks and provides the following services:

- Semaphores - Event Flags
- Mutual Exclusion Semaphores (to reduce priority inversions) - Message Mailboxes
- Message Queues
- Task Management (Create, Delete, Change Priority, Suspend/Resume etc.)
- Fixed Sized Memory Block management
- Time Management

Small footprint. µC/OS-II can be scaled to only contain the features you need for your application and thus provide a small footprint. Depending on the processor, µC/OS-II can be reduced to a little over 2K bytes of code space and 200 bytes of data space (excluding stacks).

Performancce. The execution time for most of the services provided by µC/OS-II is both constant and deterministic. This means that the execution times do not depend on the number of tasks running in your application. µC/OS-II is also very fast. The scheduler in µC/OS-II contains only four simple lines of C

Source Code. µC/OS-II comes with ALL the source code. In fact, the source code is probably the cleanest and most consistent code of any RTOS. All services provided by µC/OS-II starts with the prefix 'OS'. This makes it easier to know that the functions refer to kernel services in your application. Also, the services are neatly grouped by categories: OSMbox???() relate to message mailboxes, OSQ???() relate to message queues, OSSem???() relate to semaphore management etc.

FAA Certification. 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.

MISRA C Compliance. Continuing the quality focus, µC/OS-II is now 99% compliant with the Motor Industry Software Reliability Association (MISRA) C Coding Standards. These standards were created by MISRA to improve the reliability and predictability of C programs in critical automotive systems.. Full details of this standard can be obtained directly from the MISRA web site, http://www.misra.org.uk

Documentation. The internals of µC/OS-II are described in the book: "MicroC/OS-II, The Real-Time Kernel" which is now available worldwide from most technical bookstore.

Current CSB Ports. µC/OS-II is currently ported to the CSB637 (Atmel AT91RM9200). Application notes and free downloads are available from Micrium. A port to the CSB625 (Intel PXA255 XScale) is planned.