Edit filter log

'{{Infobox OS | name = FreeRTOS | logo = Logo freeRTOS.png | screenshot = | caption = | developer = Real Time Engineers Ltd. | family = [[Real-time operating system]]s | working state = Current | source model = [[Open-source software|Open source]] | latest release version = 10.3.1<ref>{{cite web|title=www.freertos.org/History.txt|url=https://www.freertos.org/History.txt|date=2020-02-19}}</ref> | latest release date = {{release date|2020-02-19}} | marketing target = [[Embedded devices]] | programmed in = | language = | package manager = | supported platforms = [[ARM architecture|ARM]] (ARM7, ARM9, [[ARM Cortex-M3|Cortex-M3]], [[ARM Cortex-M4|Cortex-M4]], [[ARM Cortex-M7|Cortex-M7]], [[ARM Cortex-A8|Cortex-A]]), [[Atmel AVR]], [[AVR32]], [[HCS12]], [[MicroBlaze]], [[Cortus]] (APS1, APS3, APS3R, APS5, FPF3, FPS6, FPS8), [[MSP430]], [[PIC microcontroller|PIC]], [[Renesas Technology|Renesas]] [[H8 Family|H8/S]], [[SuperH]], RX, [[x86 architecture|x86]], [[Intel 8051#Related processors|8052]], [[Freescale ColdFire|Coldfire]], [[V850]], 78K0R, Fujitsu MB91460 series, Fujitsu MB96340 series, [[Nios II]], Cortex-R4, TMS570, RM4x, Espressif ESP32, [[RISC-V]] | kernel type = [[Microkernel]] | ui = | license = [[MIT License|MIT]]<ref>{{cite web|title=FreeRTOS open source licensing|url=https://www.freertos.org/a00114.html|date=2017-12-22}}</ref> | website = {{URL|www.freertos.org}} | prog_language = | updatemodel = }} '''FreeRTOS''' is a [[real-time operating system]] kernel<ref name=EETimes2012>{{cite web|title=2011 Embedded Market Study|url=http://www.eetimes.com/electrical-engineers/education-training/webinars/4214387/2011-Embedded-Market-Study|publisher=EE Times|archiveurl=https://web.archive.org/web/20120402223224/http://www.eetimes.com/electrical-engineers/education-training/webinars/4214387/2011-Embedded-Market-Study|archivedate=2012-04-02}}</ref><ref>{{cite web|last1=Kolesnik|first1=Sergey|title=Comparing microcontroller real-time operating systems|url=http://www.embedded.com/design/operating-systems/4425751/Comparing-microcontroller-real-time-operating-systems|date=2013-12-08|quote=A kernel is not an RTOS, but this can be a confusing issue because of the inappropriate naming chosen for some popular kernels, ‘freeRTOS’ for example.}}</ref><ref>{{cite web|title=Why RTOS and What Is RTOS?|url=http://www.freertos.org/about-RTOS.html|accessdate=29 August 2014|quote=What is FreeRTOS? … The size constraints, and dedicated end application nature, rarely warrant the use of a full RTOS implementation - or indeed make the use of a full RTOS implementation possible. FreeRTOS therefore provides the core real time scheduling functionality, inter-task communication, timing and synchronisation primitives only. This means it is more accurately described as a real time kernel, or real time executive. …}}</ref> for [[embedded devices]] that has been ported to 35 [[microcontroller]] platforms. It is distributed under the [[MIT License]]. ==Implementation== FreeRTOS is designed to be small and simple. The kernel itself consists of only three C files. To make the code readable, easy to port, and maintainable, it is written mostly in [[C (programming language)|C]], but there are a few assembly functions included where needed (mostly in architecture-specific scheduler routines). FreeRTOS provides methods for multiple [[thread (computer science)|threads]] or [[task (computing)|tasks]], [[mutex]]es, [[semaphore (computer science)|semaphores]] and [[software timer]]s. A [[tickless kernel|tick-less]] mode is provided for low power applications. Thread priorities are supported. FreeRTOS applications can be completely statically allocated. Alternatively RTOS objects can be dynamically allocated with five schemes of memory allocation provided: * allocate only; * allocate and free with a very simple, fast, algorithm; * a more complex but fast allocate and free algorithm with [[Coalescence (computer science)|memory coalescence]]; * an alternative to the more complex scheme that includes memory coalescence that allows a heap to be broken across multiple memory areas. * and C library allocate and free with some mutual exclusion protection. There are none of the more advanced features typically found in [[operating systems]] like [[Linux]] or [[Microsoft Windows]], such as [[device drivers]], advanced [[memory management]], user accounts, and networking. The emphasis is on compactness and speed of execution. FreeRTOS can be thought of as a 'thread library' rather than an 'operating system', although command line interface and POSIX-like I/O abstraction add-ons are available. FreeRTOS implements multiple threads by having the host program call a thread tick method at regular short intervals. The thread tick method switches tasks depending on priority and a [[round-robin scheduling]] scheme. The usual interval is 1 to 10 milliseconds (1/1000 to 1/100 of a second), via an interrupt from a hardware timer, but this interval is often changed to suit a particular application. The download contains prepared configurations and demonstrations for every port and compiler, allowing rapid application design. The FreeRTOS.org site also contains a lot of documentation and RTOS tutorials (additional manuals and tutorials are available for a fee), as well as details of the RTOS design. ==Key features== * Book and reference manuals. * Small memory footprint, low overhead, and fast execution. * Tick-less option for low power applications. * Intended for both hobbyists and professional developers working on commercial products. * Scheduler can be configured for both preemptive or cooperative operation. * [[Coroutine]] support (coroutines in FreeRTOS are simple and lightweight [[Task (computers)|task]]s with limited use of the [[call stack]]) * Trace support through generic trace macros. Tools such as [[Tracealyzer]] by FreeRTOS partner Percepio can thereby record and visualize the runtime behavior of FreeRTOS-based systems. This includes task scheduling and kernel calls for semaphore and queue operations. Tracealyzer uses a [[freemium]] pricing strategy, offering a feature-limited free version. ==Supported architectures== {{More citations needed section|date=December 2019}}{{Div col|colwidth=15em}} * [[Altera]] [[Nios II]] * [[ARM architecture]] ** [[ARM7]] ** [[ARM9]] ** [[ARM Cortex-M]] ** [[ARM Cortex-A]] * [[Atmel]] ** [[Atmel AVR]] ** [[AVR32]] ** SAM3 / SAM4 ** SAM7 / SAM9 ** SAMD20 / SAML21 * [[[[CEVA, Inc.|CEVA]]]] **[https://www.ceva-dsp.com/product/ceva-bx1/ CEVA-BXx] **[https://www.ceva-dsp.com/product/ceva-senspro/ SensPro] **[https://www.ceva-dsp.com/product/ceva-xc16/ CEVA-XC16] **[https://www.ceva-dsp.com/product/ceva-xm6/ CEVA-XM6] **[https://www.ceva-dsp.com/product/ceva-x1/ CEVA-Xx] **[https://www.ceva-dsp.com/product/ceva-xm4/ CEVA-XM4] * [[Cortus]] ** APS1 ** APS3 ** APS3R ** APS5 ** FPS6 ** FPS8 * [[Cypress Semiconductor|Cypress]] ** [[PSoC]] * [[Energy micro|Energy Micro]] ** [[EFM32]] * [[eSi-RISC]] ** eSi-16x0 ** eSi-32x0 * [[DSP Group]] ** DBMD7 * [[Espressif]] ** [[ESP8266]]ex ** [[ESP32]] * [[Fujitsu]] ** FM3 ** MB91460 ** MB96340 * [[Freescale]] ** [[Freescale ColdFire|Coldfire]] V1 / V2 ** [[HCS12]] ** Kinetis * [[IBM]] ** [[PowerPC 400|PPC404]] / PPC405 * [[Infineon]] ** [[TriCore]] ** [[Infineon XMC4000]] * [[Intel]] ** [[x86 architecture|x86]] ** [[Intel 8051#Related processors|8052]] * [[Microchip Technology]] ** PIC18 / PIC24 / dsPIC ** PIC32 * [[Microsemi]] ** [[SmartFusion]] * [[Multiclet]] ** [[Multiclet|Multiclet P1]] * [[NXP]] ** [[NXP LPC|LPC1000]] ** [[NXP LPC|LPC2000]] ** [[NXP LPC|LPC4300]] * [[Renesas Technology|Renesas]] ** 78K0R ** RL78 ** [[H8 Family|H8/S]] ** RX600 ** RX200 ** [[SuperH]] ** [[V850]] * [[RISC-V]]<ref>{{cite web |title=Using FreeRTOS on RISC-V Microcontrollers |url=https://www.freertos.org/Using-FreeRTOS-on-RISC-V.html |publisher=FreeRTOS |accessdate=11 September 2019}}</ref> ** RV32I ** RV64I ** PULP RI5CY * [[Silicon Labs]] ** Gecko (ARM Cortex) * [[STMicroelectronics]] ** [[STM32]] ** STR7 * [[Texas Instruments]] ** [[MSP430]] ** Stellaris ** [[Hercules (processors)|Hercules]] (TMS570LS04 & RM42) * [[Xilinx]] ** [[MicroBlaze]] ** [[Xilinx#Zynq|Zynq-7000]] {{div col end}} == Derivations == === Amazon FreeRTOS === [[Amazon (company)|Amazon]] provides an extension of FreeRTOS, referred to as ''a:FreeRTOS''. This is FreeRTOS with libraries for [[Internet of Things|IOT]] support, specifically for [[Amazon Web Services]]. Since version 10.0.0 in 2017, Amazon has taken stewardship of the FreeRTOS code, including any updates to the original kernel.<ref>{{cite web |title=Amazon FreeRTOS |url=https://aws.amazon.com/freertos/ |publisher=Amazon |accessdate=28 November 2018}}</ref><ref>{{cite web |title=FAQ: Amazon FreeRTOS |url=https://www.freertos.org/FAQ_Amazon.html |publisher=FreeRTOS |accessdate=28 November 2018}}</ref><ref>{{cite web |title=Amazon FreeRTOS is a new OS for IoT |url=https://techcrunch.com/2017/11/29/amazon-freertos-is-a-new-operating-system-for-microcontroller-based-iot-devices/ |publisher=TechCrunch |accessdate=4 December 2018}}</ref> === SAFERTOS === SAFERTOS was developed as a complementary version of FreeRTOS, with common functionality but designed specifically for safety-critical implementation. FreeRTOS was subjected to [[Hazard and operability study|HAZOP]], and weaknesses were identified and resolved. The result was put through a full [[IEC 61508]] SIL 3 development life cycle, the highest level for a software-only component. SAFERTOS was developed by WITTENSTEIN High Integrity Systems, in partnership with Real Time Engineers Ltd, primary developer<ref name=EETimes2012/> of the FreeRTOS project.<ref name=FreeRTOS>{{cite web|url=http://www.freertos.org/|title=FreeRTOS|accessdate=8 Aug 2012}}</ref> Both SAFERTOS and FreeRTOS share the same scheduling algorithm, have similar [[API]]s, and are otherwise very similar,<ref name=SmartBotPaper>{{cite web|url=http://www.ece.stevens-tech.edu/~ymeng/publications/IROS08_SMARbot_meng.pdf|title=SmartBotPaper|accessdate=8 Aug 2012|url-status=dead|archiveurl=https://web.archive.org/web/20120704013911/http://www.ece.stevens-tech.edu/~ymeng/publications/IROS08_SMARbot_meng.pdf|archivedate=2012-07-04}}</ref> but they were developed with differing objectives.<ref name="freertos_a">[http://www.freertos.org/FreeRTOS-Plus/Safety_Critical_Certified/SafeRTOS.shtml Relationship between FreeRTOS and SAFE'''RTOS''']</ref> SAFERTOS was developed solely in the [[C language]] to meet requirements for certification to IEC61508.<ref name=EETimesSafetyCritical>{{cite web|url=http://www.eetimes.com/design/embedded/4007228/How-to-verify-your-compiler-for-use-in-IEC-61508-safety-critical-applications|title=EETimesSafetyCritical|accessdate=8 Aug 2012}}</ref> SAFERTOS can reside solely in the on-chip [[Read-only memory|read only memory]] of a microcontroller for standards compliance.<ref name=EmbeddedSystemsDesign>{{cite web|url=http://www.nxtbook.com/nxtbooks/cmp/esd-europe0607/index.php?startpage=32|title=Embedded Systems Design Europe|accessdate=10 Aug 2012}}</ref> When implemented in hardware memory, SAFERTOS code can only be utilized in its original, already-certified, configuration. This means certification of systems do not need to re-test the kernel portion of their designs.<ref name= TexasInstruments >{{cite web|url=http://www.ti.com/lit/wp/spry180/spry180.pdf|title=Texas Instruments|accessdate=10 Sep 2012|archive-url=https://web.archive.org/web/20130704175730/http://www.ti.com/lit/wp/spry180/spry180.pdf|archive-date=4 July 2013|url-status=dead}}</ref> SAFERTOS is included in the ROM of some Stellaris Microcontrollers<ref name="TI Stellaris Product range">[http://www.ti.com/lsds/ti/microcontroller/arm_stellaris/overview.page TI Stellaris Product range]</ref> from Texas Instruments. SAFERTOS source code does not need to be separately purchased. In this usage scenario, a C header file is used to map SAFERTOS API functions to their location in read-only memory. === OPENRTOS === OPENRTOS is a commercially-licensed version of Amazon FreeRTOS, sold by WITTENSTEIN High Integrity Systems. This product provides support and allows companies to use the Amazon FreeRTOS kernel and libraries without the a:FreeRTOS MIT license. <ref>{{cite web |title=OPENRTOS |url=https://www.highintegritysystems.com/openrtos/ |publisher=High Integrity Systems |accessdate=28 November 2018}}</ref><ref>{{cite web |title=FreeRTOS open source licensing |url=https://www.freertos.org/a00114.html#commercial |publisher=FreeRTOS |accessdate=28 November 2018}}</ref> == See also == {{Portal|Free and open-source software}} * [[Embedded operating system]] ==References== {{Reflist|25em}} == External links == {{commons category}} * {{Official website}} {{Real-time operating systems}} {{Microkernel}} [[Category:ARM operating systems]] [[Category:Embedded operating systems]] [[Category:Free software operating systems]] [[Category:Microkernel-based operating systems]] [[Category:Microkernels]] [[Category:Real-time operating systems]]'