Add support for the MCP23008 I/O extender used by the Adafruit I2C/SPI Serial backpack

Raspberry.IO.Components/Expanders/Mcp23008/Mcp23008I2cConnection.cs

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+#region References
+
+using Raspberry.IO.InterIntegratedCircuit;
+
+#endregion
+
+namespace Raspberry.IO.Components.Expanders.Mcp23008
+{
+    /// <summary>
+    /// Represents a I2C connection to a MCP23008 I/O Expander.
+    /// </summary>
+    /// <remarks>See <see cref="http://www.adafruit.com/datasheets/MCP23008.pdf"/> for more information.</remarks>
+    public class Mcp23008I2cConnection
+    {
+        #region Fields
+
+        private readonly I2cDeviceConnection connection;
+
+        #endregion
+
+        #region Instance Management
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Mcp23008I2cConnection"/> class.
+        /// </summary>
+        /// <param name="connection">The connection.</param>
+        public Mcp23008I2cConnection(I2cDeviceConnection connection)
+        {
+            this.connection = connection;
+        }
+
+        #endregion
+
+        #region Methods
+
+        /// <summary>
+        /// Sets the direction.
+        /// </summary>
+        /// <param name="pin">The pin.</param>
+        /// <param name="direction">The direction.</param>
+        public void SetDirection(Mcp23008Pin pin, Mcp23008PinDirection direction)
+        {
+            var register = Register.IODIR;
+
+            connection.WriteByte((byte)register);
+            var directions = connection.ReadByte();
+
+            var bit = (byte)((int)pin & 0xFF);
+            var newDirections = (direction == Mcp23008PinDirection.Input)
+                                    ? directions | bit
+                                    : directions & ~bit;
+
+            connection.Write(new[] { (byte)register, (byte)newDirections });
+        }
+
+        /// <summary>
+        /// Sets the polarity.
+        /// </summary>
+        /// <param name="pin">The pin.</param>
+        /// <param name="polarity">The polarity.</param>
+        public void SetPolarity(Mcp23008Pin pin, Mcp23008PinPolarity polarity)
+        {
+            var register = Register.IPOL;
+
+            connection.WriteByte((byte)register);
+            var polarities = connection.ReadByte();
+
+            var bit = (byte)((int)pin & 0xFF);
+            var newPolarities = (polarity == Mcp23008PinPolarity.Inverted)
+                                    ? polarities | bit
+                                    : polarities & ~bit;
+
+            connection.Write(new[] { (byte)register, (byte)newPolarities });
+        }
+
+        /// <summary>
+        /// Sets the resistor.
+        /// </summary>
+        /// <param name="pin">The pin.</param>
+        /// <param name="resistor">The resistor.</param>
+        public void SetResistor(Mcp23008Pin pin, Mcp23008PinResistor resistor)
+        {
+            var register = Register.GPPU;
+
+            connection.WriteByte((byte)register);
+            var resistors = connection.ReadByte();
+
+            var bit = (byte)((int)pin & 0xFF);
+            var newResistors = (resistor == Mcp23008PinResistor.PullUp)
+                                   ? resistors | bit
+                                   : resistors & ~bit;
+
+            connection.Write(new[] { (byte)register, (byte)newResistors });
+        }
+
+        /// <summary>
+        /// Sets the pin status.
+        /// </summary>
+        /// <param name="pin">The pin.</param>
+        /// <param name="enabled">if set to <c>true</c>, pin is enabled.</param>
+        public void SetPinStatus(Mcp23008Pin pin, bool enabled)
+        {
+            var register = Register.GPIO;
+
+            connection.WriteByte((byte)register);
+            var status = connection.ReadByte();
+
+            var bit = (byte)((int)pin & 0xFF);
+            var newStatus = enabled
+                                ? status | bit
+                                : status & ~bit;
+
+            connection.Write((byte)register, (byte)newStatus);
+        }
+
+
+        /// <summary>
+        /// Gets the pin status.
+        /// </summary>
+        /// <param name="pin">The pin.</param>
+        /// <returns>The pin status.</returns>
+        public bool GetPinStatus(Mcp23008Pin pin)
+        {
+            var register = Register.GPIO;
+
+            connection.WriteByte((byte)register);
+            var status = connection.ReadByte();
+
+            var bit = (byte)((int)pin & 0xFF);
+            return (status & bit) != 0x00;
+        }
+
+        /// <summary>
+        /// Toogles the specified pin.
+        /// </summary>
+        /// <param name="pin">The pin.</param>
+        public void Toogle(Mcp23008Pin pin)
+        {
+            var register = Register.GPIO;
+
+            connection.WriteByte((byte)register);
+            var status = connection.ReadByte();
+
+            var bit = (byte)((int)pin & 0xFF);
+            var bitEnabled = (status & bit) != 0x00;
+            var newBitEnabled = !bitEnabled;
+
+            var newStatus = newBitEnabled
+                                ? status | bit
+                                : status & ~bit;
+
+            connection.Write((byte)register, (byte)newStatus);
+        }
+
+        #endregion
+
+        #region Private Helpers
+
+        private enum Register
+        {
+            IODIR = 0x00,
+            IPOL = 0x01,
+            GPINTEN = 0x02,
+            DEFVAL = 0x03,
+            INTCON = 0x04,
+            IOCON = 0x05,
+            GPPU = 0x06,
+            INTF = 0x07,
+            INTCAP = 0x08,
+            GPIO = 0x09,
+            OLAT = 0x0A
+        }
+
+        #endregion
+
+    }
+}

Raspberry.IO.Components/Expanders/Mcp23008/Mcp23008InputBinaryPin.cs

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+#region References
+
+using System;
+
+#endregion
+
+namespace Raspberry.IO.Components.Expanders.Mcp23008
+{
+    /// <summary>
+    /// Represents a binary intput pin on a MCP23017 I/O expander.
+    /// </summary>
+    public class Mcp23008InputBinaryPin : IInputBinaryPin
+    {
+        #region Fields
+
+        private readonly Mcp23008I2cConnection connection;
+        private readonly Mcp23008Pin pin;
+
+        /// <summary>
+        /// The default timeout (5 seconds).
+        /// </summary>
+        public static readonly TimeSpan DefaultTimeout = TimeSpan.FromSeconds(5);
+
+        #endregion
+
+        #region Instance Management
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Mcp23008InputBinaryPin"/> class.
+        /// </summary>
+        /// <param name="connection">The connection.</param>
+        /// <param name="pin">The pin.</param>
+        /// <param name="resistor">The resistor.</param>
+        /// <param name="polarity">The polarity.</param>
+        public Mcp23008InputBinaryPin(Mcp23008I2cConnection connection, Mcp23008Pin pin,
+            Mcp23008PinResistor resistor = Mcp23008PinResistor.None,
+            Mcp23008PinPolarity polarity = Mcp23008PinPolarity.Normal)
+        {
+            this.connection = connection;
+            this.pin = pin;
+
+            connection.SetDirection(pin, Mcp23008PinDirection.Input);
+            connection.SetResistor(pin, resistor);
+            connection.SetPolarity(pin, polarity);
+        }
+
+        /// <summary>
+        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+        /// </summary>
+        public void Dispose(){}
+
+        #endregion
+
+        #region Methods
+
+        /// <summary>
+        /// Reads the state of the pin.
+        /// </summary>
+        /// <returns>
+        ///   <c>true</c> if the pin is in high state; otherwise, <c>false</c>.
+        /// </returns>
+        public bool Read()
+        {
+            return connection.GetPinStatus(pin);
+        }
+
+        /// <summary>
+        /// Waits for the specified pin to be in the specified state.
+        /// </summary>
+        /// <param name="waitForUp">if set to <c>true</c> waits for the pin to be up. Default value is <c>true</c>.</param>
+        /// <param name="timeout">The timeout. Default value is <see cref="TimeSpan.Zero"/>.</param>
+        /// <remarks>If <c>timeout</c> is set to <see cref="TimeSpan.Zero"/>, a default timeout is used instead.</remarks>
+        public void Wait(bool waitForUp = true, TimeSpan timeout = new TimeSpan())
+        {
+            var startWait = DateTime.UtcNow;
+            if (timeout == TimeSpan.Zero)
+                timeout = DefaultTimeout;
+
+            while (Read() != waitForUp)
+            {
+                if (DateTime.UtcNow - startWait >= timeout)
+                    throw new TimeoutException("A timeout occurred while waiting for pin status to change");
+            }
+        }
+
+        #endregion
+
+    }
+}

Raspberry.IO.Components/Expanders/Mcp23008/Mcp23008OutputBinaryPin.cs

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+using System;
+
+namespace Raspberry.IO.Components.Expanders.Mcp23008
+{
+    /// <summary>
+    /// Represents a binary output pin on a MCP23008 I/O expander.
+    /// </summary>
+    public class Mcp23008OutputBinaryPin : IOutputBinaryPin
+    {
+        #region Properties
+
+        private readonly Mcp23008I2cConnection connection;
+        private readonly Mcp23008Pin pin;
+
+        #endregion
+
+                #region Instance Management
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Mcp23008OutputBinaryPin"/> class.
+        /// </summary>
+        /// <param name="connection">The connection.</param>
+        /// <param name="pin">The pin.</param>
+        /// <param name="resistor">The resistor.</param>
+        /// <param name="polarity">The polarity.</param>
+        public Mcp23008OutputBinaryPin(Mcp23008I2cConnection connection, Mcp23008Pin pin,
+            Mcp23008PinResistor resistor = Mcp23008PinResistor.None,
+            Mcp23008PinPolarity polarity = Mcp23008PinPolarity.Normal)
+        {
+            this.connection = connection;
+            this.pin = pin;
+
+            connection.SetDirection(pin, Mcp23008PinDirection.Output);
+            connection.SetResistor(pin, resistor);
+            connection.SetPolarity(pin, polarity);
+        }
+
+        /// <summary>
+        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+        /// </summary>
+        public void Dispose(){}
+
+        #endregion
+
+        #region Methods
+
+        /// <summary>
+        /// Writes the value of the pin.
+        /// </summary>
+        /// <param name="state">if set to <c>true</c>, pin is set to high state.</param>
+        public void Write(bool state)
+        {
+            connection.SetPinStatus(pin, state);
+        }
+
+        #endregion
+    }
+}

Raspberry.IO.Components/Expanders/Mcp23008/Mcp23008Pin.cs

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+namespace Raspberry.IO.Components.Expanders.Mcp23008
+{
+    public enum Mcp23008Pin
+    {
+        Pin0 = 0x0001,
+        Pin1 = 0x0002,
+        Pin2 = 0x0004,
+        Pin3 = 0x0008,
+        Pin4 = 0x0010,
+        Pin5 = 0x0020,
+        Pin6 = 0x0040,
+        Pin7 = 0x0080
+    }
+}

Raspberry.IO.Components/Expanders/Mcp23008/Mcp23008PinDirection.cs

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+namespace Raspberry.IO.Components.Expanders.Mcp23008
+{
+    public enum Mcp23008PinDirection
+    {
+        Input,
+        Output
+    }
+}

Raspberry.IO.Components/Expanders/Mcp23008/Mcp23008PinExtensionMethods.cs

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+namespace Raspberry.IO.Components.Expanders.Mcp23008
+{
+    /// <summary>
+    /// Provides extension methods for MCP23008 pins.
+    /// </summary>
+    public static class Mcp23008PinExtensionMethods
+    {
+        #region Methods
+
+        /// <summary>
+        /// Creates an output binary pin.
+        /// </summary>
+        /// <param name="connection">The connection.</param>
+        /// <param name="pin">The pin.</param>
+        /// <param name="resistor">The resistor.</param>
+        /// <param name="polarity">The polarity.</param>
+        /// <returns>The pin.</returns>
+        public static Mcp23008OutputBinaryPin Out(this Mcp23008I2cConnection connection, Mcp23008Pin pin, Mcp23008PinResistor resistor = Mcp23008PinResistor.None, Mcp23008PinPolarity polarity = Mcp23008PinPolarity.Normal)
+        {
+            return new Mcp23008OutputBinaryPin(connection, pin, resistor, polarity);
+        }
+
+        /// <summary>
+        /// Creates an input binary pin.
+        /// </summary>
+        /// <param name="connection">The connection.</param>
+        /// <param name="pin">The pin.</param>
+        /// <param name="resistor">The resistor.</param>
+        /// <param name="polarity">The polarity.</param>
+        /// <returns>The pin.</returns>
+        public static Mcp23008InputBinaryPin In(this Mcp23008I2cConnection connection, Mcp23008Pin pin, Mcp23008PinResistor resistor = Mcp23008PinResistor.None, Mcp23008PinPolarity polarity = Mcp23008PinPolarity.Normal)
+        {
+            return new Mcp23008InputBinaryPin(connection, pin, resistor, polarity);
+        }
+
+        #endregion
+    }
+}

Raspberry.IO.Components/Expanders/Mcp23008/Mcp23008PinPolarity.cs

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+namespace Raspberry.IO.Components.Expanders.Mcp23008
+{
+    public enum Mcp23008PinPolarity
+    {
+        Normal,
+        Inverted
+    }
+}