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zephyr/samples/basic/blinky
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Martí Bolívar 51f55b437f twister: replace dt_compat_enabled_with_alias filter 
Originally added in 7733b94224.

This filter is not well-formed. It's meant to match nodes like
/leds/led_0 in this DTS:

/ {
	aliases {
		led0 = &led0;
	};

	leds {
		compatible = "gpio-leds";
		led0: led_0 {
			gpios = <...>;
			label = "LED 0";
		};
	};
};

Uses look like this:

    filter: dt_compat_enabled_with_alias("gpio-leds", "led0")

But notice how the led_0 node doesn't have compatible "gpio-leds";
it's actually the *parent* node that has that compatible.

Replace this with a new filter, dt_enabled_alias_with_parent_compat(),
which is used like this:

    filter: dt_enabled_alias_with_parent_compat("led0", "gpio-leds")

This has a name and argument order that makes the meaning of the
filter clearer.

Replace in-tree users with the new filter.

Deprecate the old filter and warn about its use using the standard
logging module.

Signed-off-by: Martí Bolívar <marti.bolivar@nordicsemi.no>
 		2021-03-10 15:09:09 -05:00
..
src
…
CMakeLists.txt
…
README.rst
…
prj.conf
…
sample.yaml twister: replace dt_compat_enabled_with_alias filter 2021-03-10 15:09:09 -05:00

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.