FreeRTOS

Infobox OS
name = FreeRTOS



caption =
developer = Richard Barry & FreeRTOS Team
source_model = Open source
kernel_type = Microkernel
supported_platforms = ARM, Atmel AVR, AVR32, HCS12, MicroBlaze, MSP430, PIC, Renesas H8/S, x86, 8052
ui =
family = Real-time operating systems
latest_release_version = 5.0.2
latest_release_date = July, 2008
marketing_target = Embedded devices
programmed_in =
prog_language =
language =
updatemodel =
package_manager =
working_state = Current
license = Modified GPL
website = http://www.freertos.org/

FreeRTOS is a real-time operating system for embedded devices, being ported to several microcontrollers. It is distributed under a modified version of the GPL. The modification permits users' proprietary code to remain closed source while maintaining the kernel itself as open source, thereby facilitating the use of FreeRTOS in commercial applications. The modification prevents users from comparing FreeRTOS with other RTOSs, except with permission from the author [ [http://www.freertos.org/a00114.html#exception FreeRTOS GPL exceptions] .] .

Supported architectures:
*ARM architecture
**ARM7
**ARM9
**ARM Cortex-M3
*Atmel AVR
*AVR32
*HCS12
*MicroBlaze
*MSP430
*PIC microcontroller PIC18, PIC24, dsPIC, PIC32
*Renesas H8/S
*x86
*8052

FreeRTOS is designed to be small and simple. The kernel itself is comprised of only three or four C files. To make the code readable, easy to port, and maintainable, it is written mostly in C, but there are a few assembler functions included where needed (mostly in architecture specific scheduler routines). The download contains prepared configurations and demonstrations for every port and compiler, allowing rapid application design. The FreeRTOS.org site also contains RTOS tutorials, details of the RTOS design and performance comparison results for various microcontrollers.

Key features:
*Small and simple. Very good for hobbyists who are new to OSes.
*Scheduler can be configured for both preemptive or cooperative operation.
*Coroutine support (Coroutine in FreeRTOS is a very simple and lightweight task that has very limited use of stack)

FreeRTOS has recently spawned a spin off project called SafeRTOS. SafeRTOS is based on the FreeRTOS code base but has been updated, documented, tested and audited to enable its use in IEC 61508 safety related applications.

Another related project is OpenRTOS, which has an identical code base to FreeRTOS but with different licensing. The OpenRTOS license removes all reference to the GPL and its implications. For example, one of the conditions of using FreeRTOS in a commercial product is that the user is made aware of the use of FreeRTOS and the source code must be provided upon request. OpenRTOS doesn't have this requirement.

References

See also

*Embedded operating system
*Real-time operating system

External links

* [http://www.freertos.org FreeRTOS.org]
* [http://www.safertos.com SafeRTOS]
* [http://www.openrtos.com OpenRTOS]