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Tomasz Bursztyka e18fcbba5a device: Const-ify all device driver instance pointers Now that device_api attribute is unmodified at runtime, as well as all the other attributes, it is possible to switch all device driver instance to be constant. A coccinelle rule is used for this: @r_const_dev_1 disable optional_qualifier @ @@ -struct device * +const struct device * @r_const_dev_2 disable optional_qualifier @ @@ -struct device * const +const struct device * Fixes #27399 Signed-off-by: Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>		2020-09-02 13:48:13 +02:00
..
src	device: Const-ify all device driver instance pointers	2020-09-02 13:48:13 +02:00
CMakeLists.txt	samples: make find_package(Zephyr...) REQUIRED	2020-05-29 10:47:25 +02:00
README.rst	…
prj.conf	…
sample.yaml	…

README.rst

.. _96b_carbon_multi_thread_blinky:

Basic Thread Example
####################

Overview
********

This example demonstrates spawning multiple threads using
:c:func:`K_THREAD_DEFINE`. It spawns three threads. Each thread is then defined
at compile time using K_THREAD_DEFINE.

The first two each control an LED. These LEDs, ``led0`` and ``led1``, have
loop control and timing logic controlled by separate functions.

- ``blink0()`` controls ``led0`` and has a 100ms sleep cycle
- ``blink1()`` controls ``led1`` and has a 1000ms sleep cycle

When either of these threads toggles its LED, it also pushes information into a
:ref:`FIFO <fifos_v2>` identifying the thread/LED and how many times it has
been toggled.

The third thread uses :c:func:`printk` to print the information added to the
FIFO to the device console.

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

The board must have two LEDs connected via GPIO pins. These are called "User
LEDs" on many of Zephyr's :ref:`boards`. The LEDs must be configured using the
``led0`` and ``led1`` :ref:`devicetree <dt-guide>` aliases, usually in the
:ref:`BOARD.dts file <devicetree-in-out-files>`.

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

.. code-block:: none

   Unsupported board: led0 devicetree alias is not defined
   Unsupported board: led1 devicetree alias is not defined

Building
********

For example, to build this sample for :ref:`96b_carbon_board`:

.. zephyr-app-commands::
   :zephyr-app: samples/basic/threads
   :board: 96b_carbon
   :goals: build flash
   :compact:

Change ``96b_carbon`` appropriately for other supported boards.