Leading the Embedded World

A safe, secure, and lean OS

The µ-velOSity™ RTOS is the smallest of Green Hills Software's family of real-time operating systems. It supports a wide range of microcontroller architectures and is certified to the highest industry standards for functional safety and security. Its streamlined design, and its tight integration with the MULTI® IDE makes µ-velOSity both easy-to-learn and simple-to-use and enables its users to build sophisticated automotive, industrial, and IoT solutions.

Reliable microkernel architecture

For over 40 years, Green Hills Software has been providing software products and services for mission-critical embedded systems in diverse market segments. In this decades-long journey, Green Hills Software has built the µ-velOSity RTOS as an answer to the industry's need for a safe, secure, lean, and reliable operating system for embedded microcontrollers.

At the heart of the µ-velOSity RTOS is an efficient and reliable microkernel with a minimal footprint and a concise API. The essential features that it provides are:

  • Multi-tasking functionality
  • Hardware abstraction
  • Resource allocation and management
  • Real-time response
  • MPU support for safe and secure application separation

With its small footprint, intuitive interface, and maximum performance, µ-velOSity enables you to develop reliable device software at a lower cost and get it to market faster.

Platform for multicore microcontrollers

With the ongoing consolidation of mixed criticality functions on microcontrollers, the number of cores required to support the surge of new safety and non-safety real-time applications remains large and growing. The µ-velOSity RTOS enables the industry to solve this challenge by offering support for a wide range of hardware architectures.

In addition, the µ-velOSity RTOS has been certified to multiple industry standards. These certifications prove that µ-velOSity’s reliability, safety and security enables customers to reduce the software cost of their projects as well as their time-to-market.

Finally, the µ-velOSity platform is complemented by technologies that enable developers to use an ecosystem of tools and software solutions:

  • Integration with the MULTI IDE and its state-of-the-art History® viewer, debugger, and trace analysis tools
  • Native support for the latest revisions of C and C++

Processor Support

µ-velOSity provides out-of-the-box support for:

  • ARM Cortex®-M4, M7 and ARM Cortex-R5
  • ARM Cortex-R52
  • RISC-V

Ongoing development on:

  • ARM Cortex-M23, M33, M55
  • Infineon Tricore
  • Renesas RH850


  • ISO 26262: ASIL D
  • IEC 61508: 2010 SIL 3
  • EN 50128: 2011 SIL 4
  • EN 50657: 2017 SIL 4
  • ISO 21434 (Automotive Security)
  • IEC 62443-4.1 (Industrial Security)

Comprehensive development tools

Green Hills Software has been providing tools for developing and debugging embedded systems for over 40 years. With µ-velOSity, you can leverage the most comprehensive suite of embedded development tools available to realize complete application control and visibility. These include:

  • MULTI development tools µ-velOSity include simultaneous multiple task debugging integrated with profiling and code coverage visibility for advanced source-level debugging.
  • TimeMachine® debugger helps you find bugs faster and optimize system performance. TimeMachine can greatly enhance system visibility, significantly reducing development time and helping developers to create higher performance and more reliable device software.
  • History viewer for μ-velOSity provides a natural and intuitive GUI that enables precise timing analysis, multi-tasking behavior analysis, and integration of different execution trace logs.
  • Optimizing compilers for C, C++, Embedded C++ and MISRA C generate the smallest-footprint and fastest-executing code in the industry.
  • Target simulation to provide instruction-accurate, host-based simulation environments for µ-velOSity when hardware is not yet available or in limited supply.
  • New Project Wizard for µ-velOSity provides project templates and application examples to help users get up and running with µ-velOSity in minutes.
  • Green Hills Probes for multicore hardware bring-up, low-level debugging, and trace-powered analysis debugging.
Green Hills advanced embedded development tools

Green Hills has developed the next-generation of tools for end customers developing and delivering complex embedded solutions.

Reliable solution for safety & security

Modern mictrocontrollers in automotive, industrial and IoT applications need an RTOS purpose-built for the task. Vehicle electronics are a good example where cyber security, functional safety, cost, and scalability are OEM priorities for ECU node applications with ultra-small memory footprint requirements.

On one hand, the RTOS must enable applications to fit in the limited internal-only memory of microcontrollers. On the other, the RTOS must provide application-layer enablement for new domain-specific hardware features of modern microcontrollers and expose a unified application interface across different core architectures and silicon solutions. Finally, the software solution built on the RTOS must be certified to the highest levels of safety and security. The µ-velOSity RTOS from Green Hills Software fulfills all these requirements.

The µ-velOSity RTOS and platform are also a perfect complement to the traditional use of AUTOSAR Classic in that they can cover a different class of applications, memory footprint, performance, and features.

Automotive Applications

Applications µ-velOSity is ideal for include:

  • smart e-fuses
  • drive mechanics
  • zonal and domain controllers
  • battery management systems (BMS)
  • communication modules
  • radar
  • safety islands/safety checker
  • traction, braking, and steering systems
  • and many more