HTU21DF driver

.gitignore

@@ -14,6 +14,7 @@ TestResults
 **.suo
 **.sdf  
 *.sln.docstates
+.vs/*
 
 # resharper  
 /_[Rr]e[Ss]harper.*  

Raspberry.IO.Components/Sensors/Temperature/Dht/InvalidChecksumException.cs → Raspberry.IO.Components/InvalidChecksumException.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Globalization;
 
-namespace Raspberry.IO.Components.Sensors.Temperature.Dht
+namespace Raspberry.IO.Components
 {
     public class InvalidChecksumException : Exception
     {

Raspberry.IO.Components/Raspberry.IO.Components.csproj

@@ -144,14 +144,15 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Sensors\Distance\HcSr04\HcSr04Connection.cs" />
     <Compile Include="Sensors\Distance\HcSr04\Units.cs" />
+    <Compile Include="Sensors\Humidity\Htu21df\Htu21dfConnection.cs" />
     <Compile Include="Sensors\Pressure\Bmp085\Bmp085Data.cs" />
     <Compile Include="Sensors\Pressure\Bmp085\Bmp085I2cConnectionExtensionMethods.cs" />
     <Compile Include="Sensors\Pressure\Bmp085\Bmp085Precision.cs" />
     <Compile Include="Sensors\Temperature\Dht\Dht11Connection.cs" />
     <Compile Include="Sensors\Temperature\Dht\Dht22Connection.cs" />
     <Compile Include="Sensors\Temperature\Dht\DhtConnection.cs" />
     <Compile Include="Sensors\Temperature\Dht\DhtData.cs" />
-    <Compile Include="Sensors\Temperature\Dht\InvalidChecksumException.cs" />
+    <Compile Include="InvalidChecksumException.cs" />
     <Compile Include="Sensors\Temperature\Ds18b20\Ds18b20Connection.cs" />
     <Compile Include="Sensors\VariableResistiveDividerConnection.cs" />
     <Compile Include="Sensors\Temperature\Tmp36\Tmp36Connection.cs" />

Raspberry.IO.Components/Sensors/Humidity/Htu21df/Htu21dfConnection.cs

@@ -0,0 +1,183 @@
+using System;
+using System.Threading;
+using Raspberry.IO.Components.Sensors.Temperature.Dht;
+using Raspberry.IO.InterIntegratedCircuit;
+
+namespace Raspberry.IO.Components.Sensors.Humidity.Htu21df
+{
+    /// <summary>
+    /// Connection to the HTU21D-F Adafruit humidity and temperature breakout board.
+    /// </summary>
+    /// <remarks>See <see cref="https://www.adafruit.com/datasheets/1899_HTU21D.pdf"/> for more information.</remarks>/// 
+    public class Htu21dfConnection
+    {
+        #region Helpers
+
+        public enum I2cDefs : byte
+        {
+            HTU21DF_I2CADDR = 0x40,
+            HTU21DF_READTEMP = 0xE3,
+            HTU21DF_READHUM = 0xE5,
+            HTU21DF_READTEMP_NOHOLDMASTER = 0xF3,
+            HTU21DF_READHUM_NOHOLDMASTER = 0xF5,
+            HTU21DF_WRITEREG = 0xE6,
+            HTU21DF_READREG = 0xE7,
+            HTU21DF_RESET = 0xFE,
+        }
+
+        public enum I2cReadMode
+        {
+            /// <summary>
+            /// Default. In this mode, the SCK line is blocked during the measurement process. When measurement is complete
+            /// the sensor indicates by releasing SCK and the read can continue.
+            /// </summary>
+            HoldMaster,
+
+            /// <summary>
+            /// The sensor does not hold SCK so other I2C comms can take place on the bus. The MCU (R-Pi) has to then
+            /// poll for the data. NOT CURRENTLY SUPPORTED.
+            /// </summary>
+            NoHoldMaster,
+        }
+
+        #endregion
+
+        #region Fields
+
+        private readonly I2cDeviceConnection connection;
+
+        #endregion
+
+        #region Instance Management
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Htu21dfConnection"/> class.
+        /// </summary>
+        /// <param name="connection">The connection.</param>
+        public Htu21dfConnection( I2cDeviceConnection connection )
+        {
+            this.connection = connection;
+            ReadMode = I2cReadMode.HoldMaster;
+        }
+
+        #endregion
+
+        #region Methods
+
+        public I2cReadMode ReadMode { get; set; }
+
+        /// <summary>
+        /// Init's the sensor and checks its status is OK.
+        /// </summary>
+        public void Begin()
+        {
+            Reset();
+
+            connection.WriteByte( (byte) I2cDefs.HTU21DF_READREG );
+            var status = connection.ReadByte();
+            if ( status != 0x02 )
+            {
+                throw new Exception( $"Status following reset should be 0x02. Have {status}" );
+            }
+        }
+
+        /// <summary>
+        /// Resets the sensor by power cycling. Takes about 15ms.
+        /// </summary>
+        private void Reset()
+        {
+            connection.WriteByte((byte)I2cDefs.HTU21DF_RESET);
+            Thread.Sleep(15);
+        }
+
+        /// <summary>
+        /// Reads the temperature value from the sensor.
+        /// </summary>
+        /// <returns>Temperature in degrees Centigrade.</returns>
+        public double ReadTemperature()
+        {
+            if ( ReadMode == I2cReadMode.NoHoldMaster )
+            {
+                throw new NotSupportedException( "No-Hold-Master read mode not supported." );
+            }
+
+            connection.WriteByte( (byte) I2cDefs.HTU21DF_READTEMP );
+
+            // Add delay between request and actual read
+            Thread.Sleep( 50 );
+
+            // Read 3 bytes; 2 bytes temp data and one byte checksum.
+            var readBytes = connection.Read( 3 );
+            CheckCrc( readBytes );
+
+            // Get data value from bytes 0 and 1.
+            var tVal = ( readBytes[0] << 8 ) + readBytes[1];
+
+            // Compute temp using formula from datasheet.
+            return ( ( tVal * 175.72 ) / 65536 ) - 46.85;
+        }
+
+        /// <summary>
+        /// Reads the humidity value from the sensor.
+        /// </summary>
+        /// <returns>The relative humidity value as a percentage.</returns>
+        public double ReadHumidity()
+        {
+            if (ReadMode == I2cReadMode.NoHoldMaster)
+            {
+                throw new NotSupportedException("No-Hold-Master read mode not supported.");
+            }
+
+            connection.WriteByte((byte)I2cDefs.HTU21DF_READHUM);
+
+            // Add delay between request and actual read
+            Thread.Sleep( 50 );
+
+            // Read 3 bytes; 2 bytes temp data and one byte checksum.
+            var readBytes = connection.Read( 3 );
+            CheckCrc( readBytes );
+
+            // Get data value from bytes 0 and 1.
+            var hVal = ( readBytes[0] << 8 ) + readBytes[1];
+
+            // Compute temp using formula from datasheet.
+            return ( ( (double)hVal * 125 ) / 65536 ) - 6;
+        }
+
+        /// <summary>
+        /// Calculate the CRC checksum. The result should be zero.
+        /// Thanks to the IoT-Playground - https://github.com/iot-playground.
+        /// </summary>
+        public static void CheckCrc(byte[] readData)
+        {
+            // Test cases from datasheet:
+            // sensor value = 0xDC, checkvalue is 0x79. readData = 0x00DC79.
+            // message = 0x683A, checkvalue is 0x7C. readData = 0x683A7C
+            // message = 0x4E85, checkvalue is 0x6B. readData = 0x45856B
+
+            // Create a 32-bit value with bytes of {0, val-msb, val-lsb, checksum}
+            var remainder = (uint) ( ( readData[0] << 16 ) + ( readData[1] << 8 ) + readData[2] );
+
+            // This is the x^8 + x^5 + x^4 + 1 polynomial (100110001), but shifted up to start at the left-hand
+            // side of the 24-bit value. 
+            uint divisor = 0x988000;
+
+            for ( var i = 0; i < 16; i++ )
+            {
+                if ( (remainder & (1<<(23-i))) != 0 )
+                {
+                    remainder ^= divisor;
+                }
+
+                divisor >>= 1;
+            }
+
+            if ( remainder != 0 )
+            {
+                throw new InvalidChecksumException( 0x00, remainder );
+            }
+        }
+
+        #endregion
+    }
+}

Raspberry.IO.InterIntegratedCircuit/I2cDriver.cs

@@ -491,10 +491,10 @@ private static uint GetProcessorBscAddress(Processor processor)
             switch (processor)
             {
                 case Processor.Bcm2708:
+                case Processor.BCM2835: // <- added this one JJ FIX per RB3
                     return Interop.BCM2835_BSC1_BASE;
 
                 case Processor.Bcm2709:
-                case Processor.BCM2835: // <- added this one JJ FIX per RB3
                     return Interop.BCM2836_BSC1_BASE;
 
                 default:
@@ -507,10 +507,10 @@ private static uint GetProcessorGpioAddress(Processor processor)
             switch (processor)
             {
                 case Processor.Bcm2708:
+                case Processor.BCM2835: // <- added this one JJ FIX per RB3
                     return Interop.BCM2835_GPIO_BASE;
 
                 case Processor.Bcm2709:
-                case Processor.BCM2835: // <- added this one JJ FIX per RB3
                     return Interop.BCM2836_GPIO_BASE;
 
                 default:

RaspberrySharp.IO.sln

@@ -1,6 +1,8 @@
 
 Microsoft Visual Studio Solution File, Format Version 12.00
-# Visual Studio 2012
+# Visual Studio 15
+VisualStudioVersion = 15.0.27004.2006
+MinimumVisualStudioVersion = 10.0.40219.1
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Raspberry.IO.GeneralPurpose", "Raspberry.IO.GeneralPurpose\Raspberry.IO.GeneralPurpose.csproj", "{281C71ED-C36D-408E-8BAA-75C381DC17E7}"
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{93E87796-2109-444A-8852-7174C93E6F45}"
@@ -66,6 +68,8 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Test.Gpio.Ds1307", "Tests\T
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Test.I2C.LTC2943", "Tests\Test.I2C.LTC2943\Test.I2C.LTC2943.csproj", "{6A8D4696-3291-492C-B301-AB0AFECC9440}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Test.Gpio.Htu21df", "Tests\Test.Gpio.Htu21df\Test.Gpio.Htu21df.csproj", "{04E66E09-8128-4122-BBF3-17220BC75ADA}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -176,13 +180,16 @@ Global
 		{6A8D4696-3291-492C-B301-AB0AFECC9440}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{6A8D4696-3291-492C-B301-AB0AFECC9440}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{6A8D4696-3291-492C-B301-AB0AFECC9440}.Release|Any CPU.Build.0 = Release|Any CPU
+		{04E66E09-8128-4122-BBF3-17220BC75ADA}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{04E66E09-8128-4122-BBF3-17220BC75ADA}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{04E66E09-8128-4122-BBF3-17220BC75ADA}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{04E66E09-8128-4122-BBF3-17220BC75ADA}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
 	EndGlobalSection
 	GlobalSection(NestedProjects) = preSolution
 		{15ECD485-B3FD-4B6F-8491-7489DFFC89BC} = {93E87796-2109-444A-8852-7174C93E6F45}
-		{C39D0CC3-C0F2-4B58-8779-2CCB5B52534C} = {93E87796-2109-444A-8852-7174C93E6F45}
 		{B28253A7-BB93-40F7-B41C-B4AE369174ED} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
 		{54075457-7C1D-4C8F-BE7D-CFCA34F11228} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
 		{6B5D38D3-7642-4DF9-A9AA-3AF7D00890BC} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
@@ -197,12 +204,17 @@ Global
 		{D4B87926-598E-4EAB-BA75-CD9FB253D450} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
 		{CAD5F2DD-AB2D-4145-9850-8101343E2AF5} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
 		{E401FE2A-7F73-41E7-9347-B51FEDAE71B9} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
-		{E9412139-F9EA-4E39-AB7C-CE775ED06C82} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
-		{6A8D4696-3291-492C-B301-AB0AFECC9440} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
+		{C39D0CC3-C0F2-4B58-8779-2CCB5B52534C} = {93E87796-2109-444A-8852-7174C93E6F45}
 		{17A2A965-36FA-4CDB-B2D6-AC69C9E9857F} = {C39D0CC3-C0F2-4B58-8779-2CCB5B52534C}
 		{0BB6C3CE-422E-49F2-9165-DEC06AFE1B1A} = {C39D0CC3-C0F2-4B58-8779-2CCB5B52534C}
 		{99EB3D1A-F0B7-454E-BB50-9B2F5349BC5B} = {C39D0CC3-C0F2-4B58-8779-2CCB5B52534C}
 		{CAF876A0-0FCB-44F7-96F1-53704CB6015F} = {C39D0CC3-C0F2-4B58-8779-2CCB5B52534C}
+		{E9412139-F9EA-4E39-AB7C-CE775ED06C82} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
+		{6A8D4696-3291-492C-B301-AB0AFECC9440} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
+		{04E66E09-8128-4122-BBF3-17220BC75ADA} = {15ECD485-B3FD-4B6F-8491-7489DFFC89BC}
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {7B21C3A9-4153-4372-8A05-012F51A2E4E9}
 	EndGlobalSection
 	GlobalSection(MonoDevelopProperties) = preSolution
 		Policies = $0

Tests/Test.Gpio.Htu21df/App.config

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
+    </startup>
+</configuration>

Tests/Test.Gpio.Htu21df/Program.cs

@@ -0,0 +1,38 @@
+using System;
+using System.Threading;
+using Raspberry.IO.Components.Sensors.Humidity.Htu21df;
+using Raspberry.IO.GeneralPurpose;
+using Raspberry.IO.InterIntegratedCircuit;
+
+
+namespace Test.Gpio.Htu21df
+{
+    class Program
+    {
+        static void Main()
+        {
+            const ConnectorPin sdaPin = ConnectorPin.P1Pin03;
+            const ConnectorPin sclPin = ConnectorPin.P1Pin05;
+
+            Console.WriteLine( "HTU21DF Sample: Read humidity and temperature" );
+            Console.WriteLine();
+            Console.WriteLine( "\tSDA: {0}", sdaPin );
+            Console.WriteLine( "\tSCL: {0}", sclPin );
+            Console.WriteLine();
+
+            using ( var driver = new I2cDriver( sdaPin.ToProcessor(), sclPin.ToProcessor() ) )
+            {
+                var deviceConnection = new Htu21dfConnection( driver.Connect( 0x40 ) );
+                deviceConnection.Begin();
+
+                while ( !Console.KeyAvailable )
+                {
+                    var temp = deviceConnection.ReadTemperature();
+                    var humidity = deviceConnection.ReadHumidity();
+                    Console.WriteLine( $"Temp is: {temp:F1}C. RH is {humidity:F1}%" );
+                    Thread.Sleep( 2000 );
+                }
+            }
+        }
+    }
+}

Tests/Test.Gpio.Htu21df/Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// General Information about an assembly is controlled through the following
+// set of attributes. Change these attribute values to modify the information
+// associated with an assembly.
+[assembly: AssemblyTitle("Test.Gpio.Htu21df")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("Test.Gpio.Htu21df")]
+[assembly: AssemblyCopyright("Copyright ©  2017")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// Setting ComVisible to false makes the types in this assembly not visible
+// to COM components.  If you need to access a type in this assembly from
+// COM, set the ComVisible attribute to true on that type.
+[assembly: ComVisible(false)]
+
+// The following GUID is for the ID of the typelib if this project is exposed to COM
+[assembly: Guid("04e66e09-8128-4122-bbf3-17220bc75ada")]
+
+// Version information for an assembly consists of the following four values:
+//
+//      Major Version
+//      Minor Version
+//      Build Number
+//      Revision
+//
+// You can specify all the values or you can default the Build and Revision Numbers
+// by using the '*' as shown below:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]