ARM Extends CMSIS with RTOS API and System View Description

February 27, 2012

ARM today announced the availability of Version 3.0 of the ARM® Cortex™ Microcontroller Software Interface Standard (CMSIS). CMSIS 3.0 is expanded with a standardized API for Real-Time Operating System (RTOS) kernels and support for System View Description (SVD) XML files.

The RTOS API is designed to expand existing RTOS kernels with a standardized function set that supports multiple threads, resource control, time management, and data exchange. The RTOS API allows programmers to rely on standard RTOS features that are required in source code templates, middleware libraries, and other software components.

The SVD XML files provide detailed information about a specific system and the integrated peripherals. SVD files can be used in various ways, for example to create device header files or peripheral awareness for debuggers. The SVD file format is already widely adopted by silicon vendors and debugging tools.

“The ARM Cortex-M processor series is widely supported by many different RTOS vendors, but each operating system uses a different programming interface. With the introduction of the CMSIS RTOS API we solve the challenge that software programmers face when creating software components that rely on RTOS features,” said Reinhard Keil, Director MCU Tools, ARM. “By adding the RTOS API to an existing RTOS kernel such as RTX, programmers can now use a standard set of RTOS features. This expands the common programming model of the Cortex-M series processor-based devices with standardized RTOS capabilities.”

“Developers using mbed are building increasingly complex prototypes and this created a demand for a real-time operating system that everyone can rely on,” said Simon Ford, Director of Online Tools, ARM. “The introduction of the CMSIS RTOS API standard is enabling our users to create and share reusable middleware and libraries to further push the boundaries of rapid prototyping.”

“The DAVE™ 3 development environment we provide for our XMC4000 microcontroller family is an innovative, free tool set for code generation that supports the new CMSIS RTOS API,” said Dr. Stephan Zizala, Senior Director Industrial and Multimarket Microcontrollers, Infineon Technologies. “By using the CMSIS SVD and RTOS standard, our users can fully benefit from ARM’s large ecosystem and choose the debug tools and real-time operating systems that best fit their application requirements.”

“Software reuse is today an important factor for creating efficient microcontroller applications and is fundamental to NXP's strategy of integrating industry standard ARM MCU cores with class leading peripherals,” said Jan Jaap Bezemer, Director of Marketing, microcontroller product line, NXP Semiconductors. “We welcome that ARM continues the investment into the CMSIS and extends standardization towards RTOS features that even provide functionality for the NXP LPC4300 dual-core microcontroller series.”  

“ST was one of the very first partners that adopted the ARM Cortex Microcontroller Software Interface Standard (CMSIS) and we are pleased to see its continued evolution and development,” said Daniel Colonna, Marketing Director for Microcontrollers at STMicroelectronics. “By providing a set of standard RTOS capabilities the new version of CMSIS is yet another step in enabling embedded programmers to improve productivity for ST's leading offering of Cortex-M series processor-based microcontrollers.”

“Adding the CMSIS RTOS API will further expand the user community of FreeRTOS, which is already today the most popular real-time operating system in the embedded industry,” said Richard Barry, Founder of Real Time Engineers Ltd. “Both FreeRTOS and the safety-oriented SafeRTOS implementation will be extended in the next few months with an interface for this new CMSIS standard.”

“PXROS-HR is a highly reliable real-time operating system that fully utilizes the safety features and the memory protection unit of the Cortex-M3 and Cortex-M4 processor,” said Dr. Rolf Strothmann, founder of HighTec EDV-Systeme GmbH. “We will support the CMSIS RTOS API in upcoming versions of PXROS-HR and enable the industry with an operating system that protects safety-critical threads from execution failures in other parts of the application.”

“CMSIS libraries and header files are today an integral part of the IAR Embedded Workbench, helping engineers get Cortex-M series processor-based products to market faster,” said Mike Skrtic, ARM Strategic Account Manager, IAR Systems.  “IAR Systems has a tradition of enthusiastically supporting ARM standards initiatives and will continue to do so for the new RTOS API and the SVD XML extension.” 

About CMSIS:   
The ARM Cortex Microcontroller Software Interface Standard (CMSIS) is a vendor-independent hardware abstraction layer for the Cortex-M processor series. The CMSIS enables consistent and simple software interfaces to the processor for interface peripherals, real-time operating systems, and middleware, simplifying software re-use, reducing the learning curve for new microcontroller developers and reducing the time to market for new devices.

CMSIS is supported by more than 25 ARM Partners including: Atmel, ST, Energy Micro, Freescale, Cypress, Fujitsu, Microsemi, Nuvoton, NXP, Silicon Labs, Infineon, Texas Instruments, Toshiba, IAR, SEGGER, Micrium, FreeRTOS, Code Red, Atollic, Raisonance, Altium, HighTec and Hitex

Effective immediately

CMSIS 3.0 is available for download from

ARM designs the technology that is at the heart of advanced digital products, from wireless, networking and consumer entertainment solutions to imaging, automotive, security and storage devices. ARM’s comprehensive product offering includes 32-bit RISC microprocessors, graphics processors, video engines, enabling software, cell libraries, embedded memories, high-speed connectivity products, peripherals and development tools. Combined with comprehensive design services, training, support and maintenance, and the company’s broad Partner community, they provide a total system solution that offers a fast, reliable path to market for leading electronics companies. Find out more about ARM by following these links:


ARM is a registered trademark of ARM Limited. Mali is a trademark of ARM Limited All other brands or product names are the property of their respective holders. “ARM" is used to represent ARM Holdings plc; its operating company ARM Limited; and the regional subsidiaries ARM Inc.; ARM KK; ARM Korea Limited.; ARM Taiwan Limited; ARM France SAS; ARM Consulting (Shanghai) Co. Ltd.; ARM Germany GmbH; ARM Embedded Technologies Pvt. Ltd.; ARM Norway, AS and ARM Sweden AB

Contact Details:

Alan Tringham
+44 (0) 1223 400947  

About Arm

Arm technology is building the future of computing. Our energy-efficient processor designs and software platforms have enabled advanced computing in more than 250 billion chips and our technologies securely power products from the sensor to the smartphone and the supercomputer. Together with 1,000+ technology partners, we are enabling artificial intelligence to work everywhere, and in cybersecurity, we are delivering the foundation for trust in the digital world – from chip to cloud. The future is being built on Arm.

All information is provided "as is" and without warranty or representation. This document may be shared freely, attributed and unmodified. Arm is a registered trademark of Arm Limited (or its subsidiaries). All brands or product names are the property of their respective holders. © 1995-2023 Arm Group.