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The Cortex Microcontroller Software Interface Standard (CMSIS) supports developers and vendors in creating reusable software components for ARM Cortex-M based systems.

The ARM Cortex-M3 processor is the first core from ARM specifically designed for the Microcontroller market. This core includes many common features (NVIC, Timer, Debug-hardware) needed for this market. This will enable developers to port and reuse software (e.g. a real time kernel) with much less effort to Cortex-M3 based MCUs.

With a significant amount of hardware components being identical, a large portion of the Hardware Abstraction Layer (HAL) can be identical. However, reality has shown that, in the absence of a common standard, we find a variety of HAL/driver libraries for different devices, which, as far as the Cortex-M3 part is concerned, essentially do the same thing - just differently.

The latest study of the development of the embedded market shows that software complexity and cost will increase on future projects. Reusing software and having a common standard for writing and debugging software will be essential to save cost on future developments.

With more Cortex-M3 based MCUs about to come onto the market, ARM has recognized that after solving the diversity issue on the hardware side, there is still a need to create a standard to access these hardware components.

The result of that effort is CMSIS, a framework to be extended by vendors, while taking advantage of a common API (Application Programming Interface) for core specific components and conventions that define how the device specific portions should be implemented to make developers feel right at home when they reuse code or develop new code for ARM Cortex-M based devices.

You can download the full 17 page CMSIS tutorial below.

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• To download the Doulos tutorial "Getting started with CMSIS - The Cortex Microcontroller Software Interface Standard" click here. This 17 page tutorial (pdf format) created by Doulos ARM experts, provides a thorough introduction to the new standard, and includes two tutorial examples. No registration is necessary.
  
  

• To download tutorial and code examples for the STMicroelectronics microcontroller STM32 referenced in the complete CMSIS tutorial, and an additional example on the Stellaris LM3S, supplied courtesy of Luminary Micro microcontroller, click here (both examples support MDK RealView and IAR tools).
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