Address review comments

src/devices/Arduino/ArduinoAnalogController.cs

@@ -9,6 +9,7 @@
 using System.Linq;
 using System.Text;
 using System.Threading;
+using UnitsNet;
 
 namespace Iot.Device.Arduino
 {
@@ -26,7 +27,7 @@ public ArduinoAnalogController(ArduinoBoard board,
             PinCount = _supportedPinConfigurations.Count;
 
             // Note: While the Arduino does have an external analog input reference pin, Firmata doesn't allow configuring it.
-            VoltageReference = 5.0;
+            VoltageReference = ElectricPotential.FromVolts(5.0);
         }
 
         public override int PinCount

src/devices/Arduino/ArduinoAnalogInputPin.cs

@@ -17,7 +17,7 @@ internal class ArduinoAnalogInputPin : AnalogInputPin
         private ArduinoBoard _board;
 
         public ArduinoAnalogInputPin(ArduinoBoard board, AnalogController controller, SupportedPinConfiguration configuration,
-            int pinNumber, double voltageReference)
+            int pinNumber, ElectricPotential voltageReference)
             : base(controller, pinNumber, voltageReference)
         {
             _board = board;

src/devices/Arduino/FirmataCommandSequence.cs

@@ -1,4 +1,7 @@
-using System;
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
 using System.Collections.Generic;
 using System.Text;
 

src/devices/Arduino/samples/Arduino.Monitor.cs

@@ -24,15 +24,12 @@
 
 namespace Arduino.Samples
 {
-    /// <summary>
-    /// Sample application for Ft4222
-    /// </summary>
     internal class Program
     {
         /// <summary>
         /// Main entry point
         /// </summary>
-        /// <param name="args">Unused</param>
+        /// <param name="args">The first argument gives the Port name. Default "COM4"</param>
         public static void Main(string[] args)
         {
             string portName = "COM4";

src/devices/Arduino/tests/ApiBehaviorTests.cs

@@ -1,4 +1,7 @@
-using System;
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
 using System.IO;
 using Moq;
 using Xunit;
@@ -37,7 +40,7 @@ public void InitializeWithStreamNoConnection()
             streamMock.Setup(x => x.CanWrite).Returns(true);
             streamMock.Setup(x => x.Close());
             var board = new ArduinoBoard(streamMock.Object);
-            Assert.Throws<TimeoutException>(() => board.Initialize());
+            Assert.Throws<TimeoutException>(() => board.FirmataVersion);
         }
 
         [Fact]
@@ -47,7 +50,7 @@ public void TestStreamIsReadWrite()
             _streamMock.Setup(x => x.CanRead).Returns(true);
             _streamMock.Setup(x => x.CanWrite).Returns(false);
             var board = new ArduinoBoard(_streamMock.Object);
-            Assert.Throws<NotSupportedException>(() => board.Initialize());
+            Assert.Throws<NotSupportedException>(() => board.FirmataVersion);
         }
     }
 }

src/devices/Arduino/tests/FirmataTestFixture.cs

@@ -26,7 +26,12 @@ public FirmataTestFixture()
                 _socket.NoDelay = true;
                 _networkStream = new NetworkStream(_socket, true);
                 Board = new ArduinoBoard(_networkStream);
-                Board.Initialize();
+                if (!(Board.FirmataVersion > new Version(1, 0)))
+                {
+                    // Actually not expecting to get here (but the above will throw a SocketException if the remote end is not there)
+                    throw new NotSupportedException("Very old firmware found");
+                }
+
                 Board.LogMessages += (x, y) => Console.WriteLine(x);
 
                 return;

src/devices/Common/System/Device/Analog/AnalogController.cs

@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Device.Gpio;
 using System.Linq;
+using UnitsNet;
 
 namespace System.Device.Analog
 {
@@ -42,7 +43,7 @@ public abstract int PinCount
         /// Reference voltage (the maximum voltage measurable).
         /// For some hardware, it might be necessary to manually set this value for the <see cref="AnalogInputPin.ReadVoltage"/> method to return correct values.
         /// </summary>
-        public double VoltageReference
+        public ElectricPotential VoltageReference
         {
             get;
             set;

src/devices/Common/System/Device/Analog/AnalogInputPin.cs

@@ -23,7 +23,7 @@ public abstract class AnalogInputPin : IDisposable
         /// Construct an instance of an analog pin.
         /// This is not usually called directly. Use <see cref="AnalogController.OpenPin(int)"/> instead.
         /// </summary>
-        public AnalogInputPin(AnalogController controller, int pinNumber, double voltageReference)
+        public AnalogInputPin(AnalogController controller, int pinNumber, ElectricPotential voltageReference)
         {
             Controller = controller;
             VoltageReference = voltageReference;
@@ -42,7 +42,7 @@ protected AnalogController Controller
         /// The reference voltage level to convert raw values into voltages.
         /// Some boards (i.e. the ADS111x series) always return an absolute voltage. Then this value is meaningless.
         /// </summary>
-        public double VoltageReference
+        public ElectricPotential VoltageReference
         {
             get;
         }