/// <summary>
/// Construct a standard Hd44780-compatible character display driven from the commonly-available Pcf8574 backpack.
/// </summary>
/// <param name="ioExpander">A Pcf8574 instance to use.</param>
/// <param name="columns">The number of columns in the display (defaults to 16)</param>
/// <param name="rows">The number of rows in the display (defaults to 2)</param>
/// <returns>An Hd44780 object supporting standard CharacterDisplay methods.</returns>
/// <remarks>
/// <para>
/// This factory method takes an already-created <see cref="Pcf8574"/>, creates a <see cref="FlushableParallelInterface{PortExpanderPin}"/>
/// parallel interface for it, assigns the correct pinout to this interface, and constructs a <see cref="Hd44780"/>
/// display using this interface, using the slower 4-bit mode for operation.
/// </para>
/// <para>
/// If you wish to produce custom hardware compatiable with this factory method, the correct pinout is:
/// <list type="number">
/// <item><term>Register Select (RS)</term><description>Pin 0</description></item>
/// <item><term>Read/Write (RW)</term><description>Pin 1</description></item>
/// <item><term>Enable (E)</term><description>Pin 2</description></item>
/// <item><term>Backlight Enable</term><description>Pin 3</description></item>
/// <item><term>Data 4</term><description>Pin 4</description></item>
/// <item><term>Data 5</term><description>Pin 5</description></item>
/// <item><term>Data 6</term><description>Pin 6</description></item>
/// <item><term>Data 7</term><description>Pin 7</description></item>
/// </list>
///
/// Note that when the Hd44780 is operated in 4-bit mode, only the high-nibble (D4-D7) is used, not the low-nibble.
/// </para>
/// </remarks>
public static Hd44780 GetCharacterDisplayFromPcf8574(Pcf8574 ioExpander, int columns = 16, int rows = 2)
{
var parallelInterface = new FlushableParallelInterface<PortExpanderPin>(ioExpander);
parallelInterface.RegisterSelectPin = ioExpander.Pins[0];
parallelInterface.ReadWritePin = ioExpander.Pins[1];
parallelInterface.EnablePin = ioExpander.Pins[2];
parallelInterface.DataBus.Add(ioExpander.Pins[4]);
parallelInterface.DataBus.Add(ioExpander.Pins[5]);
parallelInterface.DataBus.Add(ioExpander.Pins[6]);
parallelInterface.DataBus.Add(ioExpander.Pins[7]);
parallelInterface.Enabled = true;
return new Hd44780(parallelInterface, columns, rows, ioExpander.Pins[3]);
}
static async Task App()
{
var board = await ConnectionService.Instance.GetFirstDeviceAsync();
await board.ConnectAsync();
var ioExpander = new Pcf8574(board.I2c, false, false, false);
var display = HobbyDisplayFactories.GetCharacterDisplayFromPcf8574(ioExpander, 20, 4);
await display.WriteLine("The current date is:").ConfigureAwait(false);
while (true)
{
await display.WriteLine(DateTime.Now.ToLongTimeString()).ConfigureAwait(false);
await display.WriteLine(DateTime.Now.ToShortDateString()).ConfigureAwait(false);
await display.SetCursorPosition(0, 1);
await Task.Delay(100);
}
}
