FreeRTOS FAQs

FreeRTOS is an open source, real-time operating system that makes microcontroller-based edge devices easy to program, deploy, secure, and maintain. Distributed freely under the MIT open source license, FreeRTOS includes a kernel and a growing set of software libraries suitable for use across industry sectors and applications. This includes securely connecting your small, low-powered devices to Amazon Web Services cloud services like Amazon IoT Core or to more powerful edge devices running Amazon IoT Greengrass. FreeRTOS is built with an emphasis on reliability and ease of use.

Since 2017, Amazon FreeRTOS has been an extension of the FreeRTOS project, so we have merged the two names to eliminate customer confusion. The FreeRTOS project now includes the additional connectivity libraries, security libraries, and IoT reference integrations.

Please see the Amazon Web Services Region Table for a complete list of regions where FreeRTOS is available. You can download FreeRTOS code from GitHub irrespective of your geographic location and Amazon Web Services region availability.

FreeRTOS can be used in embedded systems spanning industrial, commercial, and consumer applications. For example, smart meters, oil pump sensors, appliances, commercial security systems, fitness trackers, and sensor networks can all benefit from FreeRTOS. Smart meters are used in homes to monitor electricity usage in real-time. Fitness trackers send health data via the user’s mobile device to the cloud for real-time monitoring or analytics. Utilities benefit from this data by enabling more efficient load balancing and power output from their generating stations. Oil pump sensors are used on oil rigs to monitor the output on wells that might be buried deep underwater. An oil rig might deploy FreeRTOS on those sensors and use an Amazon IoT Greengrass Core to locally process data from pumps and valves in real-time. The Amazon IoT Greengrass Core could then send batches of preprocessed pump sensor data to the cloud for analytics and data warehousing. To learn more about Amazon IoT Greengrass, click here.

FreeRTOS developers can download the FreeRTOS microcontroller device software from the FreeRTOS console, GitHub, or FreeRTOS.org.

Semiconductor vendors manufacture microcontrollers and modules like connectivity sensors, security peripherals, and Ethernet controllers. These microcontrollers and modules are used by OEMs to build IoT devices.

OEMs include industrial companies, commercial enterprises, and consumer brands. Microcontroller developers can use FreeRTOS to easily design and develop a connected device and IoT applications.

Enterprises can use IoT connected devices that are powered by FreeRTOS to gain business and operational efficiency.

FreeRTOS includes the FreeRTOS kernel and libraries that support connectivity, security, and over-the-air updates. The connectivity stack includes MQTT, HTTP, TCP/IP, Wi-Fi, and Bluetooth Low Energy for cloud and local connectivity. Security libraries include a standard-based Berkeley socket interface for TLS and a PKCS#11 standard interface for crypto offload.

• FreeRTOS kernel: A real-time operating system (RTOS) kernel for embedded microcontroller devices.
• MQTT: MQTT client library that you can use to create applications that publish and subscribe to MQTT topics, and connect to an MQTT-based message broker.
• HTTP Library: HTTP client library that you can use to create applications that use REST API to connect to an HTTP server.
• Wi-Fi management library: A common API layer that abstracts port-specific Wi-Fi implementations and simplifies application development.
• Bluetooth Low Energy management library: A standardized API layer that enables you to use Generic Access Profile (GAP) and Generic Attributes (GATT) profiles to create Bluetooth Low Energy applications.
• Device Defender library: Allows your FreeRTOS-based devices to work with Amazon IoT Device Defender.
• Device Shadows library: Defines functions to create, update, and delete Amazon IoT Device Shadows.
• OTA agent: Enables you to manage the notification, download, and verification of firmware updates for FreeRTOS devices.
• Greengrass discovery: A library that helps FreeRTOS devices to discover and connect to an Amazon IoT Greengrass Core.
• TLS: Transport Layer Security (TLS) interface is an optional wrapper used to abstract cryptographic implementation details of the underlying TLS stack.
• PKCS#11: A cryptographic API layer (OASIS standard) that abstracts key storage, get/set properties for cryptographic objects, and session semantics.

If you run all FreeRTOS libraries, including TLS, on the application microcontroller, you may need a microcontroller with >25MHz processing speed and >64KB RAM. If the communication and crypto stack (except for MQTT) is offloaded onto the networking processor, your microcontroller will only need 10MHz processing speed and 16KB RAM. However, these values are just approximations, as factors such as MCU architecture, compiler, and compiler optimization level may impact processing speed and RAM requirements. FreeRTOS needs 128KB of program memory per executable image stored on the microcontroller. For OTA update functionality, two executable images must be stored in program memory at the same time.

FreeRTOS currently supports a wide range of microcontrollers from our partners in the Amazon Partner Device Catalog. FreeRTOS supports 40+ architectures.

You can use the getting started guide for systematic instructions on how to run FreeRTOS on a qualified board.

Use any of the following channels to get support:

FreeRTOS Community Forums

Premium Support

Customer Support

GitHub Issues

Yes. You can access the FreeRTOS user guide from the documentation section of the getting started page.

Yes. FreeRTOS is an open-source software, so it can be modified to fit any specific needs of your application.

Yes. FreeRTOS is an open-source software distributed under the MIT license, so it can be modified to fit any specific needs of your application or project without our permission.

FreeRTOS is free to download and use under an open source MIT license.

You can explore FreeRTOS code and functionality on a Windows machine by downloading the libraries and samples ported to run on Windows. This is a set of files referred to as the FreeRTOS simulator for Windows (Windows Simulator).

No. FreeRTOS is an open source, real-time operating system for microcontrollers. You can run FreeRTOS on your chosen microcontroller by porting FreeRTOS code and validating the ported code with Amazon IoT Device Tester. To make it easier for you, we have provided IoT reference integrations and qualified ports for common microcontrollers in the Amazon Partner Device Catalog.

The FreeRTOS kernel and each individual library use semantic versioning. In semantic versioning, the version number itself (X.Y.Z) indicates if the release is a major, minor, or point release. An increment of the first version number indicates a major release, an increment of the second version number indicates a minor release, and an increment of the third number indicates a point release.

For FreeRTOS IoT reference integration releases that consist of a group of FreeRTOS libraries, date-based versioning is used. Additionally, downloads that contain the FreeRTOS kernel and additional libraries use date-based versioning. This date-based versioning follows the format YYYYMM.NN for standard releases where Y represents the year, M represents the month, and N represents the release order within the designated month (00 being the first release in a given month). A ‘Major’ denotation indicates the addition of new features and/or significant updates to multiple libraries. For example, ‘201906.00 Major’ implies that it is the first release in June 2019 and contains new features and/or significant updates. By moving semantic versioning down to the individual libraries, you can make your own assessment of the scope and impact of a new release on your application.

Yes, you can contribute code to FreeRTOS via GitHub. Please refer to Contributions.md file in GitHub for guidelines.

Amazon IoT Device Tester for FreeRTOS is a Windows/Linux/Mac test automation tool that lets semiconductor vendors self test and qualify FreeRTOS on their microcontroller boards. With Amazon IoT Device Tester, semiconductor vendors can verify whether their microcontroller boards can run FreeRTOS and be authenticated by and interoperate with Amazon IoT services.

The Amazon Web Services Device Qualification Program defines the process to get your microcontroller listed on Amazon Partner Device Catalog. The high-level overview is as follows: First, you must pass the Amazon IoT Device Tester for Amazon FreeRTOS tests. Next, log into the Amazon Partner Network Portal and upload the Amazon IoT Device Tester for FreeRTOS report. Provide reference to your source code for ported FreeRTOS interfaces to make it available to OEMs. Once the ported code and report are verified by Amazon Web Services and other device related artifacts (such as device image, data sheet, etc.) have been submitted, the device is listed in the Amazon Partner Device Catalog.

Amazon IoT Device Tester for FreeRTOS is available in all the regions where FreeRTOS is supported.

Amazon IoT Device Tester for FreeRTOS is free to use. However, you will be responsible for any costs associated with Amazon Web Services usage as part of qualification tests. On average, a single run of the Amazon IoT Device Tester would cost less than a cent. Please refer to Amazon IoT Core pricing for associated costs.

FreeRTOS does not require the use of Amazon IoT Greengrass. FreeRTOS runs on IoT endpoints and is often responsible for the ‘sensing’ and ‘acting’ in an IoT topology. FreeRTOS devices can connect directly to the cloud or connect to Amazon IoT Greengrass Core devices locally.

The Amazon IoT Greengrass discovery library is included in the FreeRTOS source code, enabling you to find and connect to an Amazon IoT Greengrass Core device. For more information, refer to the FreeRTOS user guide.

Bluetooth Low Energy support in FreeRTOS offers a standardized API layer for developers to write Bluetooth Low Energy applications that are portable across FreeRTOS qualified boards. It includes companion Android and iOS SDKs that enable an FreeRTOS device to consume Amazon IoT services using an Android or iOS device as proxy. You can use standard Generic Access Profile (GAP) and Generic Attributes (GATT) profiles to write Bluetooth Low Energy applications, and use custom profiles for MQTT over Bluetooth Low Energy, and Wi-Fi provisioning via Bluetooth Low Energy.

If you are an embedded developer that needs to create a Bluetooth Low Energy application, connect your Bluetooth Low Energy devices to Amazon IoT through an Android or iOS proxy, or use Amazon IoT features such as Amazon IoT Device Shadows, you will benefit from using Bluetooth Low Energy in FreeRTOS. The standardized Bluetooth Low Energy API for FreeRTOS allows you to code portable applications against FreeRTOS-qualified devices. If you decide to use a different microcontroller (e.g. for upgrading the product), you can use your existing Bluetooth Low Energy application code as a base for adding newer features. You can then concentrate on your application code and not worry about connectivity and security libraries underneath, which are not features that differentiate your product.

Visit our getting started page for more information on supported hardware.

You can download FreeRTOS source code from the FreeRTOS console and the FreeRTOS GitHub repository, and you can download the companion Android and iOS SDKs from GitHub. FreeRTOS source code has demo examples, and the mobile SDKs have sample applications to help you quickly get started.

No. The FreeRTOS libraries for Bluetooth Low Energy are open source and under the MIT license so developers can modify according to their specific need.

FreeRTOS supports Bluetooth Low Energy versions 4.2 and above. Bluetooth Low Energy version 4.2 raises the security bar by adding support for Bluetooth Low Energy Secure Connections, an enhanced security feature introduced in Bluetooth Low Energy version 4.2 to authenticate a peer device and create an encrypted channel.

No. FreeRTOS is providing a standardized Bluetooth Low Energy API library that interfaces with a third-party (e.g., MCU vendor) Bluetooth Low Energy stack.

Bluetooth Low Energy support in FreeRTOS enables developers to add any number of standard and custom GATT services, depending on the capabilities of the target hardware. FreeRTOS contains two customer profiles: 1) MQTT over Bluetooth Low Energy, to enable Bluetooth Low Energy devices to use Amazon IoT services, and 2) Wi-Fi provisioning over Bluetooth Low Energy, to provision Wi-Fi credentials in an IoT device using Bluetooth Low Energy.

Currently, there is no mechanism to intercept messages flowing between a Bluetooth Low Energy device and Amazon IoT. The Bluetooth Low Energy proxy only acts as a pass-through device.

However, you can use methods and classes that are provided within the proxy libraries as a starting point and modify these libraries to intercept the messages and take local action.

MQTT over Bluetooth Low Energy enables Bluetooth Low Energy devices to connect to Amazon IoT via a proxy device, as well as enables you to use other Amazon Web Services services and features including Amazon IoT Device Defender, Amazon IoT Device Shadows, and FreeRTOS OTA updates.

Yes. You can use MQTT over Wi-Fi and MQTT over Bluetooth Low Energy simultaneously as long as your device has the memory required to do so.

Amazon IoT uses the Amazon Cognito service to authenticate mobile devices with cloud services. However, you can also use X.509 certificates that are supported by FreeRTOS mobile SDKs to authenticate your proxy device with Amazon IoT.

You can use the over-the-air (OTA) update feature of FreeRTOS. Within the Amazon IoT Device Management console, all you need to do is provide a firmware image, select the devices to update, select a code signing method, and create the FreeRTOS OTA job update. For more information on the OTA update feature and code signing, refer to the FreeRTOS user guide.

Code signing enables developers to confirm the integrity and origin of firmware images scheduled for OTA deployment to FreeRTOS devices. The process confirms the integrity of firmware images using a cryptographic hash that validates that the code has not been altered or corrupted since it was signed. The process also uses public-key cryptography to sign these images with proof of origin that can be validated on the device. Using the integrated FreeRTOS OTA update device job within the Amazon IoT Device Management console, developers can upload a new firmware image, sign that image, and deliver it to a group of devices in the field. Those devices will validate the signature upon download and only install trusted code. Customers can use IAM to provide fine-grained access controls to signing tools, so only designated developers can sign and schedule new firmware updates.

No, you can also use your own signing service and upload a signed image directly into Amazon S3. You will need to modify the FreeRTOS OTA agent to accept the signature format that you choose to use.

You can find qualified hardware that support FreeRTOS OTA in the Amazon Partner Device Catalog.

FreeRTOS uses Transport Layer Security (TLS 1.2) for secure connections to the cloud. The TLS protocol ensures privacy and data integrity between two communicating applications. It ensures that a FreeRTOS device and the cloud server are mutually authenticated using X.509 certificates and that data is encrypted while it is in transit.

FreeRTOS uses a standard application interface, called PKCS #11, for encryption, digital signatures, and cryptographic object management. Cryptographic objects are kept either in dedicated storage or in the flash memory of the main microcontroller if dedicated storage is not available. If your device requires data encryption at rest, we recommend that you use dedicated cryptographic hardware to protect your encryption keys. Use the PKCS #11 API to access keys and encrypt and decrypt application data.

Security updates are provided via the FreeRTOS console, the FreeRTOS Security Updates page, and on GitHub.

We recommend that you use the over-the-air (OTA) update feature of FreeRTOS to send security patches to your FreeRTOS devices. Within the Amazon IoT Device Management console, you can provide a firmware image, select the devices to update, and create the FreeRTOS OTA job update. The code signing feature will verify the signed image on the device to ensure your device code is not compromised during deployment and updates. For more information on the OTA update feature, refer to the FreeRTOS user guide.