FreeRTOS is a small footprint, portable, preemptive, open source, real time kernel that has been designed specifically for use on microcontrollers. With more than 77,500 downloads during 2009 - FreeRTOS has become one of the most popular real time kernels available.
FreeRTOS V6.1.0 is now available. This includes some enhancements and a brand new port to the Renesas RX62N. Three RX62N compilers and two RX62N development boards are supported, making six demo projects in total. See http://www.freertos.org/a00090.html#RENESAS to access the port documentation pages, and http://www.FreeRTOS.org/History.txt for a full list of updates included in the V6.1.0 release.