RIOT in a nutshell
RIOT is an open-source microkernel-based operating system, designed to match the requirements of Internet of Things (IoT) devices and other embedded devices. These requirements include a very low memory footprint (on the order of a few kilobytes), high energy efficiency, real-time capabilities, communication stacks for both wireless and wired networks, and support for a wide range of low-power hardware.
RIOT provides a microkernel, multiple network stacks, and utilities which include cryptographic libraries, data structures (bloom filters, hash tables, priority queues), a shell and more. RIOT supports a wide range of microcontroller architectures, radio drivers, sensors, and configurations for entire platforms, e.g. Atmel SAM R21 Xplained Pro, Zolertia Z1, STM32 Discovery Boards etc. (see the list of supported hardware. Across all supported hardware (32-bit, 16-bit, and 8-bit platforms). RIOT provides a consistent API and enables ANSI C and C++ application programming, with multithreading, IPC, system timers, mutexes etc.
Contribute to RIOT
RIOT is developed by an open community that anyone is welcome to join:
- Download and contribute your code on GitHub. You can read about how to contribute in our GitHub Wiki.
- Subscribe to email@example.com to ask for help using RIOT or writing an application for RIOT (or to just stay in the loop). A searchable archive of this list is available at the RIOT user Gmane newsgroup
- Subscribe to firstname.lastname@example.org to follow and discuss kernel and network stack developement, or hardware support. A searchable archive of this list is available at the RIOT devel Gmane newsgroup
- Follow us on Twitter for news from the RIOT community.
- Regarding critical vulnerabilities we would appreciate if you give us a 90-days head-start by reporting to email@example.com, before making your information publically available
- Contact us on IRC for live support and discussions: irc.freenode.org #riot-os
The quickest start
You can run RIOT on most IoT devices, on open-access testbed hardware (e.g.
IoT-lab), and also directly as a process on your Linux/FreeBSD/OSX machine (we
call this the
native port). Try it right now in your terminal window:
git clone git://github.com/RIOT-OS/RIOT.git # assumption: git is pre-installed git checkout <LATEST_RELEASE> cd RIOT ./dist/tools/tapsetup/tapsetup # create virtual Ethernet # interfaces to connect multiple # RIOT instances cd examples/default/ make all make term
... and you are in the RIOT shell!
help to discover available commands. For further information see the
README of the
To use RIOT directly on your embedded platform, and for more hands-on details with RIOT, see @ref getting-started.
Before that, skimming through the next section is recommended (but not mandatory).
This section walks you through RIOT's structure. Once you understand this structure, you will easily find your way around in RIOT's code base.
RIOT's code base is structured into five groups.
- The kernel (
- Platform specific code (
- Device drivers (
- Libraries and network code (
- Applications for demonstrating features and for testing (
In addition RIOT includes a collection of scripts for various tasks (
well as a predefined environment for generating this documentation (
The structural groups are projected onto the directory structure of RIOT, where each of these groups resides in one or two directories in the main RIOT directory.
The following list gives a more detailed description of each of RIOT's top-level directories:
This directory contains the actual kernel. The kernel consists of the scheduler, inter-process-communication (messaging), threading, thread synchronization, and supporting data-structures and type definitions.
See @ref core for further information and API documentations.
The platform dependent code is split into two logic elements: CPUs and boards, while maintaining a strict 1-to-n relationship, a board has exactly one CPU, while a CPU can be part of n boards. The CPU part contains all generic, CPU specific code (see below).
The board part contains the specific configuration for the CPU it contains. This configuration mainly includes the peripheral configuration and pin-mapping, the configuration of on-board devices, and the CPU's clock configuration.
On top of the source and header files needed for each board, this directory
additionally may include some script and configuration files needed for
interfacing with the board. These are typically custom flash/debug scripts or
e.g. OpenOCD configuration files. For most boards, these files are located in a
dist sub-directory of the board.
See here @ref boards for further information.
For each supported CPU this directory contains a sub-directory with the name of
the CPU. These directories then contain all CPU specific configurations, such
as implementations of power management (LPM), interrupt handling and vectors,
startup code, clock initialization code and thread handling (e.g. context
switching) code. For most CPUs you will also find the linker scripts in the
periph sub-directory of each CPU you can find the implementations of
the CPU's peripheral drivers like SPI, UART, GPIO, etc. See @ref drivers_periph
for their API documentation.
Many CPUs share a certain amount of their code (e.g. all ARM Cortex-M based
CPUs share the same code for task switching and interrupt handling). This
shared code is put in its own directories, following a
scheme. Examples for this is code shared across architectures (e.g.
msp430_comon) or code shared among vendors (e.g.
See @ref cpu for more detailed informtation.
This directory contains the drivers for external devices such as network interfaces, sensors and actuators. Each device driver is put into its own sub-directory with the name of that device.
All of RIOT's device drivers are based on the peripheral driver API (e.g. SPI,
GPIO, etc.) and other RIOT modules like the
xtimer. This way the drivers are
completely platform agnostic and they don't have any dependencies into the CPU
and board code.
See @ref drivers for more details.
RIOT follows the micro-kernel design paradigm where everything is supposed to be a module. All of these modules that are not part of the hardware abstraction nor device drivers can be found in this directory. The libraries include data structures (e.g. bloom, color), crypto libraries (e.g. hashes, AES) , high-level APIs (e.g. Posix implementations), memory management (e.g. malloc), the RIOT shell and many more.
See @ref sys for a complete list of available libraries
sys/net sub-directory needs to be explicitly mentioned, as this is where
all the networking code in RIOT resides. Here you can find the network stack
implementations (e.g. the @ref net_gnrc "GNRC" stack) as well as network stack agnostic code as
header definitions or network types.
See @ref net for more details on networking code.
RIOT comes with support for a number of external libraries (e.g.
microcoap). The way they are included is
that RIOT ships with a custom Makefile for each supported library that
downloads the library and optionally applies a number of patches to make it
work with RIOT. These Makefiles and patches can be found in the
See @ref pkg for a detailed description on how this works.
Here you find a number of example applications that demonstrate certain features of RIOT. The default example found in this directory is a good starting point for anyone who is new to RIOT.
For more information best browse that directory and have a look at the
README.md files that ship with each example.
To create your own application — here or anywhere else — see @ref creating-an-application
Many features/modules in RIOT come with their own test application, which are located in this directory. In contrary to the examples these tests are mostly focusing on a single aspect than on a set of features. Despite for testing, you might consider these tests also for insights on understanding RIOT.
dist & doc
All the tooling around RIOT can be found in these two folders.
doc contains the doxygen configuration and also contains the compiled doxygen
output after running
dist directory contains tools to help you with RIOT. These
the serial terminal application
pyterm, generic scripts for flashing,
debugging, reseting (e.g. support for OpenOCD,
Jlink), as well as code enabling easy
integration to open testbeds such as the IoT-LAB.
Furthermore you can find here scripts to do all kind of code and style checks.
- @ref getting-started
- @ref creating-an-application
- @ref creating-modules