µC/OS-II
Videos
- RTOS video
- Fundamentals of Real-Time Operating Systems video (external link)
For pricing, delivery, and ordering information, contact Micrium today.
µC/OS-II Kernel

μC/OS-II 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 100% ANSI C source code and in-depth documentation. μC/OS-II runs on the largest number of processor architectures, with ports available for download from the Micrium Web site.
μC/OS-II manages up to 250 application tasks. μC/OS-II includes: semaphores; event flags; mutual-exclusion semaphores that eliminate unbounded priority inversions; message mailboxes and queues; task, time and timer management; and fixed sized memory block management.
μC/OS-II’s footprint can be scaled (between 5 Kbytes to 24 Kbytes) to only contain the features required for a specific application. 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 provides all documentation necessary to support the use of μC/OS-II in safety-critical systems. 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
Applications
µC/OS-II is used in a wide variety of industries:
- Avionics
- Medical Equipment/Devices
- Data Communications Equipment
- White Goods (Appliances)
- Mobile Phones, PDAs, MIDs
- Industrial Controls
- Consumer Electronics
- Automotive
- A wide range of embedded applications
Features
The features of µC/OS-II include:
- 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.
- Scalability--Between 5 Kbytes to 24 Kbytes I Max interrupt disable time: 200 clock cycles (typical configuration, ARM9, no wait states).
- Sufficiently robust to meet rigorous safety-critical system requirements
- Complete ANSI C source code is available for a 30-day trial use.
Multi-Threaded Applications
µC/OS-II allows developers to produce multi-threaded applications, vital to the development of safety-critical systems. Thanks to improved integration with IAR Embedded Workbench for ARM, developers can access all the inherent non-reentrant features of C/C++ in a thread-safe manner.
Application developers who write code for use in multi-threaded environments will find the support critical when protecting shared objects using system locks, file-stream locks, and thread-local storage (TLS) in multi-threaded environments.
Micrium and IAR collaborated in providing the first thread-safe support in µC/OS-II for the IAR DLIB run-time library. Protection for such non-reentrant functions as strtok(), rand(), errno() and more are local to each thread. Global and static variables typically used by these functions are protected by the Micrium kernel.
| Who should use this RTOS? | Developers who want to save time on their current and next embedded system project, and who want the cleanest, most popular, and robust RTOS on the market. |
| Supported Processors | See complete list in Processor Chart |
| Maximum ROM Footprint (Unscaled) | 24 Kbytes |
| Minimum ROM Footprint (Scaled) | 6 Kbytes |
| Number of Kernel Services | 10 different using 80 API calls |
| Multitasking Model | Preemptive |
| Code Execution Entities | Tasks, ISRs |
| Dynamic Objects | Static and Dynamic |
| Data Movement | Message Mailboxes (unlimited)and Message Queues (unlimited) |
| Semaphores - Full Counting | Yes (unlimited) |
| Mutexes - With Priority Inheritance | Yes (priority calling) |
| Event Flags | Yes (unlimited), configurable for 8, 16, or 32 bits |
| Memory Partitions - RAM Management | Yes |
| Timers | Yes (unlimited) |
Communications Stacks and Middleware
| Requires an RTOS | RTOS not Required | |
|---|---|---|
| μC/TCP-IP TCP/IP Networking Small RAM/ROM footprint, IP v4 |
X | - |
| μC/USB Host USB Host stack |
- | X |
| μC/USB Device USB Device stack |
- | X |
| μC/USB OTG USB Host and Device stack |
- | X |
| μC/FS FAT and FAT-Free File System |
- | X |
| μC/CAN CAN Open Stack |
- | X |
| μC/GUI Graphical User Interface |
- | X |
The current μC/USB-Host version is V3.10. In version 3.20 it will be available to run without a RTOS
Plug-Ins and Tools
μC/OS-II Kernel Awareness Plug-In (KA) allows for the display of μC/OS-II’s internal data structures in a series of windows integrated with the C-SPY Debugger from IAR’s Embedded Workbench. This allows you to examine each task, semaphore, mutex, mailbox, queue, and event flag group, as well as tasks waiting on kernel objects.
Monitoring
Use μC/Probe to visualize all μC/OS-II -based applications allowing a design engineer to monitor and change values in a product at run time. μC/Probe interfaces to any embedded target whether or not it has a real-time kernel, and works with any (8-bit, 16, bit, 32-bit, 64-bit CPU or DSP. μC/Probe saves valuable time throughout product design, and can also serve as a product’s user interface.
Processor Architectures
Architectures supported by μC/OS-II include:
| Company | Architecture |
|---|---|
| Actel | Cortex-M1 |
| Altera | Nios II, Cortex-M1 |
| Analog Devices | AduC7xxx (ARM7), ADSP-21xx, Blackfin 5xx, SHARC |
| ARM | ARM7, ARM9, ARM11, Cortex-M1, Cortex-M3 |
| Atmel | SAM7 (ARM7), SAM9(ARM9), AVR, AVR 32 |
| Freescale | 9S08, 9S12, Coldfire, PowerPC, i.MX |
| Fujitsu | FR50 |
| Infineon | TriCore, 80C16x |
| Intel | 80x86 |
| Lattice | Micro32 |
| Luminary Micro | Cortex-M3 |
| Microchip | PIC24, dsPIC33, PIC32 (MIPS) |
| MIPS | R3000, R4000 |
| NXP | ARM7, ARM9, Cortex-M3 |
| Renesas | H8, M16C, M32C, R32C, RL78, SH, 78Kx, V850 |
| Samsung | ARM7, ARM9 |
| ST | 80C16x, STR7 (ARM7), STR9 (ARM9), STM32 (Cortex-M3) |
| TI | MSP430, TMS320, TMS470, TMS570, Cortex-R4 (ARM7) |
| Toshiba | Cortex-M3 |
| Xilinx | MicroBlaze, PowerPC |
| ZILOG | Z80, eZ80 |
For pricing, delivery, and ordering information, contact Micrium today.