36e8526046
The API was based on the assumption that GPIO ports are mapped in memory
sanely, so that a `GPIO_PORT(num)` macro would work allow for constant
folding when `num` is known and still be efficient when it is not.
Some MCUs, however, will need a look up tables to efficiently translate
GPIO port numbers to the port's base address. This will prevent the use
of such a `GPIO_PORT(num)` macro in constant initializers.
As a result, we rather provide `GPIO_PORT_0`, `GPIO_PORT_1`, etc. macros
for each GPIO port present (regardless of MCU naming scheme), as well as
`GPIO_PORT_A`, `GPIO_PORT_B`, etc. macros if (and only if) the MCU port
naming scheme uses letters rather than numbers.
These can be defined as macros to the peripheral base address even when
those are randomly mapped into the address space. In addition, a C
function `gpio_port()` replaces the role of the `GPIO_PORT()` and
`gpio_port_num()` the `GPIO_PORT_NUM()` macro. Those functions will
still be implemented as efficient as possible and will allow constant
folding where it was formerly possible. Hence, there is no downside for
MCUs with sane peripheral memory mapping, but it is highly beneficial
for the crazy ones.
There are also two benefits for the non-crazy MCUs:
1. We can now test for valid port numbers with `#ifdef GPIO_PORT_<NUM>`
- This directly benefits the test in `tests/periph/gpio_ll`, which
can now provide a valid GPIO port for each and every board
- Writing to invalid memory mapped I/O addresses was treated as
triggering undefined behavior by the compiler and used as a
optimization opportunity
2. We can now detect at compile time if the naming scheme of the MCU
uses letters or numbers, and produce more user friendly output.
- This is directly applied in the test app
The friendly Operating System for IoT!
RIOT is an open-source microcontroller operating system, designed to match the requirements of Internet of Things (IoT) devices and other embedded devices. It supports a range of devices that are typically found in the Internet of Things (IoT): 8-bit, 16-bit and 32-bit microcontrollers.
RIOT is based on the following design principles: energy-efficiency, real-time capabilities, small memory footprint, modularity, and uniform API access, independent of the underlying hardware (this API offers partial POSIX compliance).
RIOT is developed by an international open source community which is independent of specific vendors (e.g. similarly to the Linux community). RIOT is licensed with LGPLv2.1, a copyleft license which fosters indirect business models around the free open-source software platform provided by RIOT, e.g. it is possible to link closed-source code with the LGPL code.
Features
RIOT provides features including, but not limited to:
- a preemptive, tickless scheduler with priorities
- flexible memory management
- high resolution, long-term timers
- MTD abstraction layer
- File System integration
- support 200+ boards based on AVR, MSP430, ESP8266, ESP32, RISC-V, ARM7 and ARM Cortex-M
- the native port allows to run RIOT as-is on Linux and BSD. Multiple instances of RIOT running on a single machine can also be interconnected via a simple virtual Ethernet bridge or via a simulated IEEE 802.15.4 network (ZEP)
- IPv6
- 6LoWPAN (RFC4944, RFC6282, and RFC6775)
- UDP
- RPL (storing mode, P2P mode)
- CoAP
- OTA updates via SUIT
- MQTT
- USB (device mode)
- Display / Touchscreen support
- CCN-Lite
- LoRaWAN
- UWB
- Bluetooth (BLE) via NimBLE
Getting RIOT
The most convenient way to get RIOT is to clone it via Git
$ git clone https://github.com/RIOT-OS/RIOT
this will ensure that you get all the newest features and bug fixes with the caveat of an ever changing work environment.
If you prefer things more stable, you can download the source code of one of our quarter annual releases via Github as ZIP file or tarball. You can also checkout a release in a cloned Git repository using
$ git pull --tags
$ git checkout <YYYY.MM>
For more details on our release cycle, check our documentation.
Getting Started
- You want to start the RIOT? Just follow our quickstart guide or try this tutorial. For specific toolchain installation, follow instructions in the getting started page.
- The RIOT API itself can be built from the code using doxygen. The latest version of the documentation is uploaded daily to doc.riot-os.org.
Using Windows? Use this guide to setup the development environment.
Forum
Do you have a question, want to discuss a new feature, or just want to present your latest project using RIOT? Come over to our forum and post to your hearts content.
Contribute
To contribute something to RIOT, please refer to our contributing document.
Mailing Lists
- RIOT commits: commits@riot-os.org
- Github notifications: notifications@riot-os.org
License
- Most of the code developed by the RIOT community is licensed under the GNU Lesser General Public License (LGPL) version 2.1 as published by the Free Software Foundation.
- Some external sources, especially files developed by SICS are published under a separate license.
All code files contain licensing information.
For more information, see the RIOT website: