Blinky sample


Blinky is a simple application which blinks an LED forever.

The source code shows how to configure GPIO pins as outputs, then turn them on and off.


The board must have an LED connected via a GPIO pin. These are called “User LEDs” on many of Zephyr’s Supported Boards. The LED must be configured using the led0 Devicetree Guide alias in the BOARD.dts file.

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

Unsupported board: led0 devicetree alias is not defined

Building and Running

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

west build -b reel_board samples/basic/blinky
west flash

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