The Pre-Certified Flexible Safety RTOS

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The Flexible Safety RTOS™ is a real-time operating system that has been pre-certified to key industry standards for functional safety. Powered by Micrium's field-proven and highly reliable μC/OS-II kernel, the Flexible Safety RTOS is suitable for applications that need to comply with any of the following safety standards:



ISO 26262 - ASIL D


IEC 61508 - SIL 3


IEC 62304 - Class C


EN 50128 - SIL 4

Because the Flexible Safety RTOS has been independently pre-certified, it eliminates the need to manage and understand all the artifacts required to certifying the real-time kernel as part of your application, significantly reducing the time and effort for certification.

For Aerospace applications leading to DO-178 certification, a pre-certified approach is not the preferred method. In these cases, we can provide you certification services within your project itself to achieve the functional safety objectives. This includes safety audits and integration into your specific development processes.


Confidence in Certification

The Flexible Safety RTOS is reviewed and certified by teams from the well-known functional safety assessment bodies at TÜV Rheinland and TÜV Süd. The team of experts assesses the software and development process to validate the safety capabilities of the Flexible Safety RTOS, resulting in an official certificate of compliance that we provide.


Flexible Certification by Design

The development and certification process has been architected to maximize the design flexibility for users while maintaining the safety capabilities of the RTOS.


Easily change the chosen MCU to a different device with the same certified core

Change compiler switches or use compiler updates

The Flexible Safety RTOS allows for the integration of middleware components that do not have inherent safety capabilities while maintaining the system's safety integrity


Multi-Core Features

The Flexible Safety RTOS is ready for use in microcontrollers with multiple cores.

With asynchronous multi-processing (AMP), an independent instance of the Flexible Safety RTOS is supported on each core.


Cross-Core Communication

Message queues between all cores

Cross-Core Synchronization

Signal events across all cores

Cross-Core Task Management

Control task execution on all cores

The AMP solution for multi-core processing guarantees the deterministic behavior and highest real-time capabilities.


Compiler Independence

The Flexible Safety RTOS certification is structured such that a certified Compiler is not required. Thus we can perform certification of the Flexible Safety RTOS with all ANSI-C compilers. Popular compilers options are:


IAR Embedded Workbench


Tasking Compiler

Keil Microcontroller Development Kit (MDK)

HighTec Development Platform


Supported Services

The Flexible Safety RTOS provides all the features and services you expect from a high-performance real-time kernel. This includes managed memory protection that is designed to guard against possible memory corruption, a key consideration for functional safety systems.


Multi-Tasking Scheduler

Memory Management

Shared Memory

Space Protection

Hardware Monitoring

Software Timers

Mutexes & Semaphores

Event Flags



Hook Functions



The Flexible Safety RTOS supports a wide range of hardware platforms from well-known semiconductor providers including ST Microelectronics, Texas Instruments, and NXP among others. We are continuously working on new devices.

The Flexible Safety RTOS is delivered in the form of a Cert-Kit which is a prepackaged solution for your specified MCU, compiler, and functional safety standard.  The Cert-Kit forms the basis of all documents required for the certification of a safety-critical product using an RTOS.

Because the Flexible Safety RTOS is pre-certified, only compliance with the Safety Manual needs to be proven to obtain certification. This eliminates the need to manage and understand all the certification artifacts of the real-time kernel, significantly reducing the time to certification. Cert-Kits are provided with a TÜV certificate, independent proof of standards compliance, which reduces the certification risk and therefore project risk.


Validation Software Included

In addition to extensive documentation, the Flexible Safety RTOS comes with validation software to verify that the RTOS has been properly implemented by the customer. This is similar to running software found in semiconductor manufacturer’s starter kits. However, instead of a demo application, complete validation software is included.

The system delivered with the validation software will initially be used to verify that the customer has correctly implemented the pre-certified Flexible Safety RTOS source code and that the real-time kernel has been properly configured. To achieve this, the validation software generates a report on the respective evaluation board that serves as proof for this step. Then, the hardware configuration can be adapted to that of the safety-critical project, or optionally, the hardware programming interface (often also called BSP) can be completely replaced. A repeat execution of the validation software generates a report that proves the RTOS is functioning correctly.


Deliverables Provided

The Flexible Safety RTOS comes with the kernel source code and extensive documentation:


Source Code

Real-Time Kernel

Validation Test Software

Reference Board Support Package



Safety Manual

Target Integration Manual

Reference and User Manuals


Safety Certificate

Revision / Compliance List

Flexible Safety RTOS and complete Cert-Kits are available for industrial controls, medical, transportation, and aerospace applications based on Micrium's industry-leading µC/OS-II kernel.