4 The <b>CMSIS-RTOS v2 (CMSIS-RTOS2)</b> provides generic RTOS interfaces for Arm® Cortex® processor-based
5 devices. It provides a standardized API for software components that require RTOS functionality and gives therefore serious
6 benefits to the users and the software industry:
7 - CMSIS-RTOS2 provides basic features that are required in many applications.
8 - The unified feature set of the CMSIS-RTOS2 reduces learning efforts and simplifies sharing of software components.
9 - Middleware components that use the CMSIS-RTOS2 are RTOS agnostic and are easier to adapt.
10 - Standard project templates of the CMSIS-RTOS2 may be shipped with freely available CMSIS-RTOS2 implementations.
12 \note The CMSIS-RTOS API Version 2 defines a minimum feature set. Implementations with extended features may be provided by
15 The CMSIS-RTOS2 manages the resources of the microcontroller system and implements the concept of parallel threads that run
18 Applications frequently require several concurrent activities. CMSIS-RTOS2 can manage multiple concurrent activities at the
19 time when they are needed. Each activity gets a separate thread which executes a specific task and this simplifies the
20 overall program structure. The CMSIS-RTOS2 system is scalable and additional threads can be added easily at a later time.
21 Threads have a priority allowing faster execution of time-critical parts of a user application.
23 The CMSIS-RTOS2 offers services needed in many real-time applications, for example, periodical activation of timer functions,
24 memory management, and message exchange between threads with time limits.
26 The CMSIS-RTOS2 addresses the following new requirements:
27 - Dynamic object creation no longer requires static memory, static memory buffers are now optional.
29 - Support for Armv8-M architecture that provides a secure and non-secure state of code execution.
31 - Provisions for message passing in multi-core systems.
32 - Full support of C++ run-time environments.
33 - C interface which is binary compatible across
34 <a href="http://infocenter.arm.com/help/topic/com.arm.doc.subset.swdev.abi/index.html">ABI compatible compilers</a>.
36 As a consequence of these requirements the CMSIS-RTOS2 has the following fundamental modifications:
37 - The functions osXxxxNew replace osXxxxCreate functions; osXxxxNew and osXxxxDelete create and destroy objects.
38 - The C function \c main is no longer started as a thread (this was an optional feature in CMSIS-RTOS v1).
39 - Functions that return osEvent have been replaced.
41 CMSIS-RTOS2 provides an translation layer to <a class="el" href="../../RTOS/html/index.html">CMSIS-RTOS v1</a>. It
42 is possible to intermix \ref rtos_api2 and <a class="el" href="../../RTOS/html/functionOverview.html">CMSIS-RTOS C API v1</a>
43 within the same application. Over time, you may migrate to the new API as explained in \ref os2Migration.
45 CMSIS-RTOS2 is not POSIX compliant, but has provisions to enable a C++11/C++14 interface.
47 The following sections provide further details about CMSIS-RTOS2 and the RTX reference implementation.
48 - \ref rtos_revisionHistory documents changes made in each version for CMSIS-RTOS v2 and RTX v5.
49 - \ref genRTOS2IF provides an overview about the APIs available with CMSIS-RTOS v2.
50 - \ref functionOverview lists the CMSIS-RTOS2 API functions and the header file %cmsis_os2.h.
52 - \ref rtosValidation describes the validation suite that is publicly available.
53 - \ref os2Migration shows how to use CMSIS-RTOS2 in existing projects and lists function differences to CMSIS-RTOS v1.
55 - \ref rtx5_impl provides general information about the operation and usage of RTX v5.
57 - \ref rtx_safety provides comprehensive instructions for highly reliable applications.
60 \section directory CMSIS-RTOS2 in ARM::CMSIS Pack
62 The following files relevant to CMSIS-RTOS2 are present in the <b>ARM::CMSIS</b> Pack directories:
64 :----------------------------|:-----------------------------------------------------------------------
65 \b CMSIS/Documentation/RTOS2 | This documentation
66 \b CMSIS/RTOS2/Include | \ref cmsis_os2_h
67 \b CMSIS/RTOS2/RTX | CMSIS-RTOS2 reference implementation based on RTX version 5
68 \b CMSIS/RTOS2/Source | Generic <b>OS tick</b> implementations for various processors based on \ref rtos_os_tick_api
69 \b CMSIS/RTOS2/Template | Compatibility layer to <a class="el" href="../../RTOS/html/index.html">CMSIS-RTOS v1</a>