add support for using flow control with BP35A1

Author: smdn

src/Smdn.Devices.BP35XX/Smdn.Devices.BP35XX/BP35A1.cs

@@ -21,6 +21,14 @@ public class BP35A1 : BP35Base {
   /// </remarks>
   internal const BP35UartBaudRate DefaultValueForBP35UartBaudRate = BP35UartBaudRate.Baud115200;
 
+  /// <summary>
+  /// Refer to the initial value of the flow control for UART setting in the BP35A1.
+  /// </summary>
+  /// <remarks>
+  /// See 'BP35A1コマンドリファレンス 3.32. WUART (プロダクト設定コマンド)' for detailed specifications.
+  /// </remarks>
+  internal const bool DefaultValueForUseFlowControl = false;
+
   public static ValueTask<BP35A1> CreateAsync(
     string? serialPortName,
     IServiceProvider? serviceProvider = null,
@@ -78,5 +86,6 @@ private BP35A1(
 
   private protected class BP35A1SerialPortStreamFactory(BP35A1Configurations configurations) : SerialPortStreamFactory {
     public override BP35UartBaudRate BaudRate { get; } = configurations.BaudRate;
+    public override bool UseFlowControl { get; } = configurations.UseFlowControl;
   }
 }

src/Smdn.Devices.BP35XX/Smdn.Devices.BP35XX/BP35A1Configurations.cs

@@ -13,6 +13,11 @@ public sealed class BP35A1Configurations {
   /// </summary>
   public BP35UartBaudRate BaudRate { get; set; } = BP35A1.DefaultValueForBP35UartBaudRate;
 
+  /// <summary>
+  /// Gets or sets a value indicating whether or not to use the Request-to-Send (RTS) hardware flow control for communicating with the device.
+  /// </summary>
+  public bool UseFlowControl { get; set; } = BP35A1.DefaultValueForUseFlowControl;
+
   /// <summary>
   /// Gets or sets a value indicating whether or not to attempt to load the configuration from flash memory during initialization.
   /// </summary>

src/Smdn.Devices.BP35XX/Smdn.Devices.BP35XX/BP35Base.SerialPortStreamFactory.cs

@@ -12,6 +12,7 @@ partial class BP35Base {
 #pragma warning restore IDE0040
   private protected abstract class SerialPortStreamFactory : IBP35SerialPortStreamFactory {
     public abstract BP35UartBaudRate BaudRate { get; }
+    public abstract bool UseFlowControl { get; }
 
     public void Dispose()
     {
@@ -46,9 +47,9 @@ public Stream CreateSerialPortStream(string? serialPortName)
         dataBits: 8,
         stopBits: StopBits.One
       ) {
-        Handshake = Handshake.None, // TODO: RequestToSend
+        Handshake = UseFlowControl ? Handshake.RequestToSend : Handshake.None,
         DtrEnable = false,
-        RtsEnable = false,
+        RtsEnable = UseFlowControl,
         NewLine = CRLF,
       };
 #pragma warning restore CA2000