Add AIP31068 LCD binding with contrast control, sample, and docs

src/devices/CharacterLcd/Aip31068Lcd.cs

@@ -0,0 +1,167 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Device;
+using System.Device.I2c;
+using System.Drawing;
+
+namespace Iot.Device.CharacterLcd
+{
+    /// <summary>
+    /// 16x2 LCD controller based on the AIP31068, which exposes an HD44780 compatible interface with
+    /// an integrated I2C controller.
+    /// </summary>
+    public class Aip31068Lcd : Hd44780
+    {
+        private const byte ContrastMask = 0x3F;
+        private const byte ContrastSetCommand = 0x70;
+        private const byte PowerIconContrastCommand = 0x50;
+        private const byte IconDisplayFlag = 0x08;
+        private const byte BoosterFlag = 0x04;
+        private const byte FollowerControlCommand = 0x6C;
+        private const byte InternalOscillatorCommand = 0x14;
+        private const byte DefaultContrast = 0x20;
+
+        private byte _contrast;
+        private bool _iconDisplayEnabled;
+        private bool _boosterEnabled;
+
+        // Static members must appear before non-static members (SA1204)
+        private static byte NormalizeContrast(byte value)
+        {
+            return value > ContrastMask ? ContrastMask : (byte)(value & ContrastMask);
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Aip31068Lcd"/> class using the specified I2C device.
+        /// </summary>
+        /// <param name="device">The I2C device used to communicate with the LCD controller.</param>
+        /// <param name="contrast">Initial contrast value. Valid range: 0-63.</param>
+        /// <param name="iconDisplayEnabled">True to enable the icon display, false to disable it.</param>
+        /// <param name="boosterEnabled">True to enable the internal voltage booster, false to disable it.</param>
+        public Aip31068Lcd(I2cDevice device, byte contrast = DefaultContrast, bool iconDisplayEnabled = false, bool boosterEnabled = true)
+            : base(new Size(16, 2), LcdInterface.CreateI2c(device, true))
+        {
+            _contrast = NormalizeContrast(contrast);
+            _iconDisplayEnabled = iconDisplayEnabled;
+            _boosterEnabled = boosterEnabled;
+
+            InitializeController();
+        }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="Aip31068Lcd"/> class using an existing LCD interface.
+        /// </summary>
+        /// <param name="lcdInterface">The LCD interface used to communicate with the controller.</param>
+        /// <param name="contrast">Initial contrast value. Valid range: 0-63.</param>
+        /// <param name="iconDisplayEnabled">True to enable the icon display, false to disable it.</param>
+        /// <param name="boosterEnabled">True to enable the internal voltage booster, false to disable it.</param>
+        public Aip31068Lcd(LcdInterface lcdInterface, byte contrast = DefaultContrast, bool iconDisplayEnabled = false, bool boosterEnabled = true)
+            : base(new Size(16, 2), lcdInterface)
+        {
+            _contrast = NormalizeContrast(contrast);
+            _iconDisplayEnabled = iconDisplayEnabled;
+            _boosterEnabled = boosterEnabled;
+
+            InitializeController();
+        }
+
+        /// <summary>
+        /// Gets or sets the display contrast (0-63).
+        /// </summary>
+        public byte Contrast
+        {
+            get => _contrast;
+            set
+            {
+                byte normalized = NormalizeContrast(value);
+                if (_contrast == normalized)
+                {
+                    return;
+                }
+
+                _contrast = normalized;
+                UpdateContrastConfiguration();
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the icon display is enabled.
+        /// </summary>
+        public bool IconDisplayEnabled
+        {
+            get => _iconDisplayEnabled;
+            set
+            {
+                if (_iconDisplayEnabled == value)
+                {
+                    return;
+                }
+
+                _iconDisplayEnabled = value;
+                UpdateContrastConfiguration();
+            }
+        }
+
+        /// <summary>
+        /// Gets or sets a value indicating whether the voltage booster is enabled.
+        /// </summary>
+        public bool BoosterEnabled
+        {
+            get => _boosterEnabled;
+            set
+            {
+                if (_boosterEnabled == value)
+                {
+                    return;
+                }
+
+                _boosterEnabled = value;
+                UpdateContrastConfiguration();
+            }
+        }
+
+        private void InitializeController()
+        {
+            EnterExtendedInstructionSet();
+            SendCommandAndWait(InternalOscillatorCommand);
+            SendContrastCommands();
+            SendCommandAndWait(FollowerControlCommand);
+            DelayHelper.DelayMilliseconds(200, allowThreadYield: true);
+            ExitExtendedInstructionSet();
+
+            // Re-issue the standard configuration commands expected after extended setup.
+            SendCommandAndWait((byte)_displayControl);
+            Clear();
+            SendCommandAndWait((byte)_displayMode);
+        }
+
+        private void UpdateContrastConfiguration()
+        {
+            EnterExtendedInstructionSet();
+            SendContrastCommands();
+            ExitExtendedInstructionSet();
+        }
+
+        private void SendContrastCommands()
+        {
+            SendCommandAndWait((byte)(ContrastSetCommand | (_contrast & 0x0F)));
+            byte value = (byte)(PowerIconContrastCommand
+                | (_iconDisplayEnabled ? IconDisplayFlag : 0)
+                | (_boosterEnabled ? BoosterFlag : 0)
+                | ((_contrast >> 4) & 0x03));
+            SendCommandAndWait(value);
+        }
+
+        private void EnterExtendedInstructionSet()
+        {
+            SendCommandAndWait((byte)(_displayFunction | DisplayFunction.ExtendedInstructionSet));
+        }
+
+        private void ExitExtendedInstructionSet()
+        {
+            SendCommandAndWait((byte)(_displayFunction & ~DisplayFunction.ExtendedInstructionSet));
+        }
+    }
+}
+

src/devices/CharacterLcd/CharacterLcd.csproj

@@ -8,6 +8,7 @@
     <Compile Include="Hd44780.cs" />
     <Compile Include="ICharacterLcd.cs" />
     <Compile Include="CharacterLcdExtensions.cs" />
+    <Compile Include="Aip31068Lcd.cs" />
     <Compile Include="Lcd1602.cs" />
     <Compile Include="Lcd2004.cs" />
     <Compile Include="LcdConsole.cs" />

src/devices/CharacterLcd/README.md

@@ -44,6 +44,18 @@ using LcdRgb lcd = new LcdRgb(new Size(16, 2), i2cLcdDevice, i2cRgbDevice);
 }
 ```
 
+AIP31068 based LCDs expose the same HD44780 compatible instruction set but require an extended
+initialization sequence. The <code>Aip31068Lcd</code> binding performs the necessary configuration and allows
+adjusting the display contrast:
+
+```csharp
+var i2cDevice = I2cDevice.Create(new I2cConnectionSettings(busId: 1, deviceAddress: 0x3E));
+using Aip31068Lcd lcd = new(i2cDevice);
+lcd.Clear();
+lcd.Write("Hello from AIP31068!");
+lcd.Contrast = 36; // optional: tune the contrast (0-63)
+```
+
 PCF8574T/PCF8574AT Sample
 The I2C backpack based on the PCF8574T/AT IC uses specific pin mapping, to consume this device binding on this backpack use like so
 

src/devices/CharacterLcd/samples/Aip31068Sample.cs

@@ -0,0 +1,87 @@
+// 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.Device.I2c;
+using System.Threading;
+
+namespace Iot.Device.CharacterLcd.Samples
+{
+    internal static class Aip31068Sample
+    {
+        private const int DefaultBusId = 1;
+        private const int DefaultAddress = 0x3E;
+
+        public static void Run()
+        {
+            using I2cDevice device = I2cDevice.Create(new I2cConnectionSettings(DefaultBusId, DefaultAddress));
+            using Aip31068Lcd lcd = new(device);
+
+            lcd.Clear();
+            lcd.SetCursorPosition(0, 0);
+            lcd.Write("AIP31068 sample");
+            DisplayContrast(lcd);
+
+            Console.WriteLine("AIP31068 LCD sample ready.");
+            Console.WriteLine("Use '+' or '-' to adjust contrast, 'B' to toggle the booster, 'I' to toggle icons.");
+            Console.WriteLine("Press Esc to exit.");
+
+            while (true)
+            {
+                if (!Console.KeyAvailable)
+                {
+                    Thread.Sleep(50);
+                    continue;
+                }
+
+                ConsoleKeyInfo key = Console.ReadKey(intercept: true);
+                if (key.Key == ConsoleKey.Escape)
+                {
+                    break;
+                }
+
+                switch (key.Key)
+                {
+                    case ConsoleKey.Add:
+                    case ConsoleKey.OemPlus:
+                        AdjustContrast(lcd, +1);
+                        break;
+                    case ConsoleKey.Subtract:
+                    case ConsoleKey.OemMinus:
+                        AdjustContrast(lcd, -1);
+                        break;
+                    case ConsoleKey.B:
+                        lcd.BoosterEnabled = !lcd.BoosterEnabled;
+                        Console.WriteLine($"Booster {(lcd.BoosterEnabled ? "enabled" : "disabled")}.");
+                        break;
+                    case ConsoleKey.I:
+                        lcd.IconDisplayEnabled = !lcd.IconDisplayEnabled;
+                        Console.WriteLine($"Icon display {(lcd.IconDisplayEnabled ? "enabled" : "disabled")}.");
+                        break;
+                    default:
+                        continue;
+                }
+
+                DisplayContrast(lcd);
+            }
+
+            lcd.Clear();
+            lcd.Write("Goodbye!");
+        }
+
+        private static void AdjustContrast(Aip31068Lcd lcd, int delta)
+        {
+            int contrast = lcd.Contrast + delta;
+            contrast = Math.Clamp(contrast, 0, 63);
+            lcd.Contrast = (byte)contrast;
+            Console.WriteLine($"Contrast set to {lcd.Contrast}.");
+        }
+
+        private static void DisplayContrast(Aip31068Lcd lcd)
+        {
+            lcd.SetCursorPosition(0, 1);
+            lcd.Write($"Contrast: {lcd.Contrast:D2}  ");
+        }
+    }
+}
+

src/devices/CharacterLcd/samples/Program.cs

@@ -19,6 +19,7 @@
 // UsingGroveRgbDisplay();
 // UsingHd44780OverI2C();
 // UsingHd44780OverI2CAndArduino();
+// UsingAip31068Lcd();
 UsingShiftRegister();
 
 void UsingGpioPins()
@@ -87,6 +88,11 @@ void UsingHd44780OverI2CAndArduino()
     ExtendedSample.Test(hd44780);
 }
 
+void UsingAip31068Lcd()
+{
+    Aip31068Sample.Run();
+}
+
 void UsingShiftRegister()
 {
     int registerSelectPin = 1;