无法从COM端口读取串行响应

Question

我正在尝试使用UWP平台对设备执行请求响应模式。我可以使用此代码成功进行写操作，但是读操作始终返回0个字节。我使用交叉连接电缆来确认与另一个串行端口的写入。使用UWP示例，我可以返回和读取响应，但是下面的代码永远不会读取任何数据。

https://github.com/Microsoft/Windows-universal-samples/blob/master/Samples/CustomSerialDeviceAccess

下面是我尝试发送请求并接收响应的方法

async public void FindDevices()
        {
            string comDeviceSelector = SerialDevice.GetDeviceSelector("COM2");
            var UsbDevices = await DeviceInformation.FindAllAsync(comDeviceSelector);

            var device = await SerialDevice.FromIdAsync(UsbDevices.First().Id);
            device.BaudRate = 115200;
            device.DataBits = 8;
            device.StopBits = SerialStopBitCount.One;
            device.Parity = SerialParity.None;
            device.Handshake = SerialHandshake.None;
            device.BreakSignalState = false;
            device.IsDataTerminalReadyEnabled = false;
            device.IsRequestToSendEnabled = false;

            device.WriteTimeout = TimeSpan.FromMilliseconds(50);
            device.ReadTimeout = TimeSpan.FromSeconds(30);

            var writer = new DataWriter(device.OutputStream);

            var requestWriteAccess = new byte[] { 0xA5, 0x3F, 0x02, 0x07, 0x00, 0x01, 0xB3, 0xE7, 0x0F, 0x00, 0x10, 0x3E};
            writer.WriteBytes(requestWriteAccess);
            var bytesWritten = writer.StoreAsync().AsTask();
            writer.DetachStream();
            writer = null;

            uint ReadBufferLength = 1024;
            var reader = new DataReader(device.InputStream);
            reader.InputStreamOptions = InputStreamOptions.Partial;
            var readTask = reader.LoadAsync(ReadBufferLength).AsTask();
            var bytesRead = await readTask;
        }

以下是我的appxmanifest中的内容：

<DeviceCapability Name="serialcommunication">
      <Device Id="any">
        <Function Type="name:serialPort"/>
      </Device>
    </DeviceCapability>