zephyr

History

Torsten Rasmussen 1cccc8a8fe cmake: increase minimal required version to 3.20.0 Move to CMake 3.20.0. At the Toolchain WG it was decided to move to CMake 3.20.0. The main reason for increasing CMake version is better toolchain support. Better toolchain support is added in the following CMake versions: - armclang, CMake 3.15 - Intel oneAPI, CMake 3.20 - IAR, CMake 3.15 and 3.20 Signed-off-by: Torsten Rasmussen <Torsten.Rasmussen@nordicsemi.no>		2021-08-20 09:47:34 +02:00
..
src	…
CMakeLists.txt	cmake: increase minimal required version to 3.20.0	2021-08-20 09:47:34 +02:00
README.rst	…
prj.conf	…
sample.yaml	…

README.rst

.. _blinky-sample:

Blinky
######

Overview
********

Blinky is a simple application which blinks an LED forever using the :ref:`GPIO
API <gpio_api>`. The source code shows how to configure GPIO pins as outputs,
then turn them on and off.

See :ref:`pwm-blinky-sample` for a sample which uses the PWM API to blink an
LED.

.. _blinky-sample-requirements:

Requirements
************

You will see this error if you try to build Blinky for an unsupported board:

.. code-block:: none

   Unsupported board: led0 devicetree alias is not defined

The board must have an LED connected via a GPIO pin. These are called "User
LEDs" on many of Zephyr's :ref:`boards`. The LED must be configured using the
``led0`` :ref:`devicetree <dt-guide>` alias. This is usually done in the
:ref:`BOARD.dts file <devicetree-in-out-files>` or a :ref:`devicetree overlay
<set-devicetree-overlays>`.

Building and Running
********************

Build and flash Blinky as follows, changing ``reel_board`` for your board:

.. zephyr-app-commands::
   :zephyr-app: samples/basic/blinky
   :board: reel_board
   :goals: build flash
   :compact:

After flashing, the LED starts to blink. Blinky does not print to the console.