AWS has announced a LTS (Long Term Support) version of its open source real-time operating system FreeRTOS for microcontrollers. FreeRTOS is mainly used in small edge devices with low power consumption. The LTS versions should remain functionally stable for two years and only receive security patches and critical error corrections.

Only recommended updates to the FreeRTOS kernel and some libraries should be included in the updates. Changes to public APIs, file structures or creation processes that could affect the applications are left out. This should eliminate the risk of updates damaging an existing application.

Revised and checked The first version of FreeRTOS LTS is FreeRTOS 202012. 00 LTS. In addition to the FreeRTOS kernel, Long Term Support includes a number of FreeRTOS libraries that are required for embedded and IoT applications as well as for the secure connection of microcontroller devices to the cloud. These include FreeRTOS + TCP, coreMQTT, coreHTTP, corePKCS 11, coreJSON and AWS IoT Device Shadow.

These libraries stay at least until 31. December 2022 currently. They do not depend on any other libraries than the standard C library. Each LTS library has its own GitHub repository. This should make it easier for developers to integrate and update libraries in their FreeRTOS projects.

In addition, the LTS libraries were validated with the tool for automated test CBMC (C Bounded Model Checker) for memory security, to reduce vulnerability to a buffer overflow. In addition, AWS checked the LTS libraries for MISRA-C compliance and subjected them to additional code quality checks, including a static coverity analysis. In the download area of ​​the FreeRTOS LTS libraries there is a corresponding LTS code quality checklist.

(sun)