Initial commit for blinky

README.rst

@@ -0,0 +1,97 @@
+.. zephyr:code-sample:: blinky
+   :name: Blinky
+   :relevant-api: gpio_interface
+
+   Blink an LED forever using the GPIO API.
+
+Overview
+********
+
+The Blinky sample blinks an LED forever using the :ref:`GPIO API <gpio_api>`.
+
+The source code shows how to:
+
+#. Get a pin specification from the :ref:`devicetree <dt-guide>` as a
+   :c:struct:`gpio_dt_spec`
+#. Configure the GPIO pin as an output
+#. Toggle the pin forever
+
+See :zephyr:code-sample:`pwm-blinky` for a similar sample that uses the PWM API instead.
+
+.. _blinky-sample-requirements:
+
+Requirements
+************
+
+Your board must:
+
+#. Have an LED connected via a GPIO pin (these are called "User LEDs" on many of
+   Zephyr's :ref:`boards`).
+#. Have the LED configured using the ``led0`` devicetree alias.
+
+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 and messages with the current LED state
+are printed on the console. If a runtime error occurs, the sample exits without
+printing to the console.
+
+Build errors
+************
+
+You will see a build error at the source code line defining the ``struct
+gpio_dt_spec led`` variable if you try to build Blinky for an unsupported
+board.
+
+On GCC-based toolchains, the error looks like this:
+
+.. code-block:: none
+
+   error: '__device_dts_ord_DT_N_ALIAS_led_P_gpios_IDX_0_PH_ORD' undeclared here (not in a function)
+
+Adding board support
+********************
+
+To add support for your board, add something like this to your devicetree:
+
+.. code-block:: DTS
+
+   / {
+   	aliases {
+   		led0 = &myled0;
+   	};
+
+   	leds {
+   		compatible = "gpio-leds";
+   		myled0: led_0 {
+   			gpios = <&gpio0 13 GPIO_ACTIVE_LOW>;
+                };
+   	};
+   };
+
+The above sets your board's ``led0`` alias to use pin 13 on GPIO controller
+``gpio0``. The pin flags :c:macro:`GPIO_ACTIVE_HIGH` mean the LED is on when
+the pin is set to its high state, and off when the pin is in its low state.
+
+Tips:
+
+- See :dtcompatible:`gpio-leds` for more information on defining GPIO-based LEDs
+  in devicetree.
+
+- If you're not sure what to do, check the devicetrees for supported boards which
+  use the same SoC as your target. See :ref:`get-devicetree-outputs` for details.
+
+- See :zephyr_file:`include/zephyr/dt-bindings/gpio/gpio.h` for the flags you can use
+  in devicetree.
+
+- If the LED is built in to your board hardware, the alias should be defined in
+  your :ref:`BOARD.dts file <devicetree-in-out-files>`. Otherwise, you can
+  define one in a :ref:`devicetree overlay <set-devicetree-overlays>`.