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zephyr/samples/basic/rgb_led
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Gerard Marull-Paretas c7b5b3c419 samples: migrate includes to contain <zephyr/...> prefix 
In order to bring consistency in-tree, migrate all samples to the use
the new prefix <zephyr/...>. Note that the conversion has been scripted:

```python
from pathlib import Path
import re

EXTENSIONS = ("c", "h", "cpp", "rst")

for p in Path(".").glob("samples/**/*"):
    if not p.is_file() or p.suffix and p.suffix[1:] not in EXTENSIONS:
        continue

    content = ""
    with open(p) as f:
        for line in f:
            m = re.match(r"^(.*)#include <(.*)>(.*)$", line)
            if (m and
                not m.group(2).startswith("zephyr/") and
                (Path(".") / "include" / "zephyr" / m.group(2)).exists()):
                content += (
                    m.group(1) +
                    "#include <zephyr/" + m.group(2) +">" +
                    m.group(3) + "\n"
                )
            else:
                content += line

    with open(p, "w") as f:
        f.write(content)
```

Signed-off-by: Gerard Marull-Paretas <gerard.marull@nordicsemi.no>
 		2022-05-06 11:29:59 +02:00
..
src samples: migrate includes to contain <zephyr/...> prefix 2022-05-06 11:29:59 +02:00
CMakeLists.txt cmake: increase minimal required version to 3.20.0 2021-08-20 09:47:34 +02:00
README.rst samples: basic: rgb_led: use pwm_dt_spec 2022-04-28 11:29:38 +02:00
prj.conf
…
sample.yaml
…

README.rst 

.. _rgb-led-sample:

PWM: RGB LED
############

Overview
********

This is a sample app which drives an RGB LED using PWM.

There are three single-color component LEDs in an RGB LED. Each component LED
is driven by a PWM port where the pulse width is changed from zero to the period
indicated in Devicetree. Such period should be fast enough to be above the
flicker fusion threshold (the minimum flicker rate where the LED is perceived as
being steady). The sample causes each LED component to step from dark to max
brightness. Three **for** loops (one for each component LED) generate a gradual
range of color changes from the RGB LED, and the sample repeats forever.

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

The board must have red, green, and blue LEDs connected via PWM output channels.

The LED PWM channels must be configured using the following :ref:`devicetree
<dt-guide>` aliases, usually in the :ref:`BOARD.dts file
<devicetree-in-out-files>`:

- ``red-pwm-led``
- ``green-pwm-led``
- ``blue-pwm-led``

You will see at least one of these errors if you try to build this sample for
an unsupported board:

.. code-block:: none

   Unsupported board: red-pwm-led devicetree alias is not defined
   Unsupported board: green-pwm-led devicetree alias is not defined
   Unsupported board: blue-pwm-led devicetree alias is not defined

See :zephyr_file:`boards/arm/hexiwear_k64/hexiwear_k64.dts` for an example
:file:`BOARD.dts` file which supports this sample.

Wiring
******

No additional wiring is necessary if the required devicetree aliases refer to
hardware that is already connected to LEDs on the board.

Otherwise, LEDs should be connected to the appropriate PWM channels.

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

For example, to build and flash this board for :ref:`hexiwear_k64`:

.. zephyr-app-commands::
   :zephyr-app: samples/basic/rgb_led
   :board: hexiwear_k64
   :goals: build flash
   :compact:

Change ``hexiwear_k64`` appropriately for other supported boards.