Real-Time Kernel: µC/OS 5

The Micrium µC/OS 5 RTOS is a preemptive, highly portable, and scalable real-time kernel. Designed for ease of use on a huge number of CPU architectures, it is a key component of Micrium OS.

Looking for µC/OS-III or µC/OS-II products?

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Key Values

Portable. Offering unprecedented ease-of-use, the µC/OS 5 kernel is delivered with complete source code and in-depth documentation. The kernel runs on a huge number of processor architectures.

Scalable. The kernel allows for unlimited tasks and kernel objects. The kernel's memory footprint can be scaled down to contain only the features required for your application, typically 4–14 KBytes of code space and 2 KByte of data space.

Reliable. The kernel includes debugging feature that reduces development time. The kernels provide extensive range checking, including checks for pointers passed in API calls, task level services from ISRs, arguments within allowable range, and for valid specified options.

Efficient. Micrium's kernel also includes valuable runtime statistics, making the internals of your application observable. Identify performance bottlenecks, and optimize power usage, early in your development cycle.


The features of the Micrium µC/OS 5 kernel include:

  • Preemptive multitasking real-time kernel with optional round-robin scheduling
  • Delivered with complete, clean, consistent source code with in-depth documentation
  • Highly scalable: Unlimited number of tasks, priorities and kernel objects
  • Resource-efficient: 4K to 14K bytes code space, 2K+ bytes data space
  • Very low interrupt disable time
  • Extensive performance measurement metrics (configurable)


Memory Footprint

Scalable Yes (compile and run-time configurable)
ROM (Min-Max) 6K-24K (bytes)
RAM 2K+ (bytes)

Task Management

Multitasking model Preemptive
Maximum number of tasks Unlimited
Scheduling Real-time scheduler
Round-robin scheduler
Run-time stack checking Configurable
Catch/delete task that return Yes
Kernal time base Configurable (constant and dynamic tick rate)
Timeout on calls Yes (prevents deadlocks)
Interrupt Disable Time Near Zero

Kernel Services

Critical sections Yes
Event Flags Yes
Lock/Unlock scheduler Yes
Memory partitions Yes (prevents fragmentation)
Message queues Yes
Monitors Yes
Mutual exclusion semaphores Yes (full priority inheritance and nestable)
Semaphores Yes
Software timers Yes
Task registers Yes
Task suspend/resume Yes

Micrium µC/OS 5 Kernel versus µC/OS-II and µC/OS-III

Which real-time kernel should you use? Micrium’s kernels meet different needs.

Compare Micrium's real-time kernels

Supported CPU Architectures

The following table lists CPU architectures for which Micrium OS ports are readily available. New ports can be written easily or adapted to your specific needs either by yourself or Micrium.

You can find example projects that demonstrate some of our currently-available kernel ports in the Download Center.

Manufacturer CPU
Altera Nios II SoC FPGA (Cortex-A)
Analog Devices Blackfin ADSP-CM4xx (Cortex-M)

ARM7, ARM9, ARM11, Cortex-A5, Cortex-A7, Cortex-A8, Cortex-A9, Cortex-A15, Cortex-A17, Cortex-R4, Cortex-R5, Cortex-R7, Cortex-M0, Cortex-M0+, Cortex-M1, Cortex-M3, Cortex-M4(F), Cortex-M7

ATMEL SAM3, SAM4, SAM7, SAM9, SAMA5 (ARM Cortex-based)
Cypress Semiconductors PSoC 4, PSoC 5 (Cortex-M)
Infineon XMC4000 (Cortex-M)
Microsemi SmartFusion2 (Cortex-M)
Microsoft Emulation
NXP i.MX, Kinetis (Cortex-M), LPC (Cortex-M), LPC (ARM7 / ARM9), VFxxx (Cortex-A & Cortex-M)
Renesas RX100, RX200, RX600, RX700, RZ/A (Cortex-A), RZ/T1 (Cortex-R & Cortex-M), RZ/N1 (Cortex-A & Cortex-M), R-IN32M3 (Cortex-M)
Silicon Labs Gecko (Cortex-M)
ST Microelectronics STM32F (Cortex-M), STM32H (Cortex-M), STM32L (Cortex-M), STR9
Texas Instruments MSP432 (Cortex-M), Hercules RM (Cortex-R), Hercules TMS570 (Cortex-R)
POSIX Emulation
Xilinx MicroBlaze Zynq-7000 (Cortex-A), Zynq Ultrascale+ MPSoC (Cortex-A & Cortex-R)

You can also contact our sales department for more information about supported platforms or port development.


Licensing Packages That Meet Your Needs

Check out our licensing page for more information.


Micrium's user documentation for Micrium OS is available online on the Micrium documentation site.

Contact us today and start working with Micrium OS