Download FreeRTOS

Quality RTOS & Embedded Software

Simplifying Authenticated Cloud Connectivity for Any Device.
Designing an energy efficient and cloud-connected IoT solution with CoAP.
Introducing FreeRTOS Kernel version 11.0.0:
FreeRTOS Roadmap and Code Contribution process.
OPC-UA over TSN with FreeRTOS.

FreeRTOS FAQ Contents
[Contact and Support]

How to get the most from the FreeRTOS support forum

My application does not run, what could be wrong?

What Is This All About?
What is a Real Time Operating System (RTOS)?
What is a Real Time Kernel?
What is a Real Time Scheduler?
How do I use FreeRTOS?
How do I get started?
Why use an RTOS?

What is a Long Term Support (LTS) release?
Which libraries are covered under FreeRTOS Long Term Support (LTS)
What is the support period for FreeRTOS LTS libraries?
What are the benefits of using FreeRTOS LTS libraries?
Where do I obtain the FreeRTOS LTS libraries?
How do I integrate FreeRTOS LTS libraries into my project?
How do I find information on and download the FreeRTOS LTS patches?
What is the software license for FreeRTOS LTS?
Do I have to pay to use FreeRTOS LTS libraries?
Who is releasing and supporting FreeRTOS LTS?
What is the release cycle for FreeRTOS LTS?
What is the SLA for security updates and critical bug fixes?
Can I get support for more than two years?

What is the FreeRTOS Extended Maintenance Plan (EMP)?
What is the FreeRTOS Extended Maintenance Plan (EMP)?
Why should I use FreeRTOS EMP?
What are the main features of FreeRTOS EMP?
Where can I find information about pricing and getting started?

AWS IoT Reference Integrations
How can I add my microcontroller-based board to the IoT Reference Integrations page?
How do I get started with FreeRTOS LTS libraries, if I want to use AWS IoT features?

GitHub Repository Structure & Versioning
How are FreeRTOS Git repositories structured?
How are FreeRTOS libraries versioned?
Which library packages are available?
How do I obtain and use individual FreeRTOS libraries?
How do I obtain a FreeRTOS distribution package?

Why have Amazon taken stewardship of FreeRTOS?
Do I have to be an Amazon Web Services (AWS) customer to use FreeRTOS?
Can I use FreeRTOS to connect to any cloud service?
Are Amazon also investing in the FreeRTOS kernel as a standalone component?
Have Amazon forked FreeRTOS?

How is FreeRTOS tested?
What are the mtCOVERAGE_TEST_MARKER() macros?

Why are there so many API functions?
Why is there a separate API for use in interrupts?
Why do APIs for use in ISRs set xHigherPriorityTaskWoken rather than actually perform a context switch?
Why are semaphores as large as queues?
How do I use semaphores efficiently?
Why can't a task delete itself by exiting its implementing function?
Why does my delay of N ticks not result in exactly N ticks * tick_period in delay?

Will FreeRTOS run under Windows?
Are the NNN development tools supported?
Is the NNN microcontroller supported?
How do I create a new port?
What is the difference between an official port, and an unsupported port?

Memory Usage, Boot Times, Context Switch Times
How much RAM does FreeRTOS use?
How much ROM does FreeRTOS use?
How long does FreeRTOS take to boot?
How long does a context switch take?
Why do queues use that much RAM?
How can I reduce the amount of RAM used?
How is RAM allocated to tasks?
How is RAM allocated to queues?
How big should a task stack be?

Can I use FreeRTOS in a commercial project?
Do I have to give away my application source code if I use FreeRTOS?
I require a commercial license, is there anything available?
Can I use FreeRTOS in a safety critical application?

How are tasks of equal priority scheduled?
How are tasks that share the idle priority scheduled?

Can a context switch occur within an ISR?
How do I write an RTOS safe ISR?
Can interrupts be nested?

Copyright (C) Amazon Web Services, Inc. or its affiliates. All rights reserved.