samples: Added analog_input sample

Add a sample to demonstrate how to use analogRead API

Signed-off-by: TOKITA Hiroshi <[email protected]>

samples/analog_input/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+set(DTC_OVERLAY_FILE $ENV{ZEPHYR_BASE}/../modules/lib/Arduino-Zephyr-API/variants/${BOARD}/${BOARD}.overlay)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(analog_input)
+
+target_sources(app PRIVATE src/main.cpp)
+zephyr_compile_options(-Wno-unused-variable -Wno-comment)

samples/analog_input/README.rst

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+.. _arduino_nano_33_ble_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`.
+
+These three each control an LED. These LEDs, ``LED_BUILTIN``, ``D10`` and ``D11``, have
+loop control and timing logic controlled by separate functions.
+
+- ``blink0()`` controls ``LED_BUILTIN`` and has a 100ms sleep cycle
+- ``blink1()`` controls ``D11`` and has a 1000ms sleep cycle
+- ``loop()`` controls ``D10`` and has a 300ms sleep cycle
+
+Requirements
+************
+
+The board must have two LEDs connected via GPIO pins and one builtin LED. These are called "User
+LEDs" on many of Zephyr's :ref:`boards`. The LEDs must be mapped using the `<board_name_pinmap.h>`
+``LED_BUILTIN``, ``D10`` and ``D11`` to the :ref:`devicetree <dt-guide>` aliases, in the
+variants folder.
+
+You will see one of these errors if you try to build this sample for an
+unsupported board:
+
+.. code-block:: none
+
+   Unsupported board: LED_BUILTIN devicetree alias is not defined
+   Unsupported board: D11 devicetree alias is not defined
+
+Building
+********
+
+For example, to build this sample for :ref:`arduino_nano_33_ble`:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/basic/arduino-threads
+   :board: arduino_nano_33_ble
+   :goals: build flash
+   :compact:
+
+Change ``arduino_nano_33_ble`` appropriately for other supported boards.

samples/analog_input/prj.conf

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+CONFIG_ADC=y
+CONFIG_ARDUINO_API=y

samples/analog_input/src/main.cpp

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+/*
+ * Copyright (c) 2022 TOKITA Hiroshi <[email protected]>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <Arduino.h>
+
+const int analog_input = A0;    // select the input pin for the potentiometer
+const int ledPin = LED_BUILTIN;      // select the pin for the LED
+const float wait_factor = 1.f;
+
+void setup() {
+  pinMode(ledPin, OUTPUT);
+}
+
+void loop() {
+  int value = 0;
+
+  value = analogRead(analog_input);
+
+  /* Blinks slowly when the input voltage is high */
+
+  digitalWrite(ledPin, HIGH);
+  delay(value * wait_factor);
+
+  digitalWrite(ledPin, LOW);
+  delay(value * wait_factor);
+}
+