Read Only (Polling)

LibUsbDotNet

LibUsbDotNet 2.2.8 Read Only (Polling)
LibUsbDotNet on SourceForge

Read Only (Polling): Console Application Description
  1. Opens a USB device by vendor and product id.

  2. Opens a UsbEndpointReader class for reading.

  3. Reads and displays usb device output from Ep01 until no data is received for 5 seconds.

Example
CopyC#
using System;
using System.Text;
using LibUsbDotNet;
using LibUsbDotNet.Main;

namespace Examples
{
    internal class ReadPolling
    {
        public static UsbDevice MyUsbDevice;

        #region SET YOUR USB Vendor and Product ID!

        public static UsbDeviceFinder MyUsbFinder = new UsbDeviceFinder(1234, 1);

        #endregion

        public static void Main(string[] args)
        {
            ErrorCode ec = ErrorCode.None;

            try
            {
                // Find and open the usb device.
                MyUsbDevice = UsbDevice.OpenUsbDevice(MyUsbFinder);

                // If the device is open and ready
                if (MyUsbDevice == null) throw new Exception("Device Not Found.");

                // If this is a "whole" usb device (libusb-win32, linux libusb-1.0)
                // it exposes an IUsbDevice interface. If not (WinUSB) the 
                // 'wholeUsbDevice' variable will be null indicating this is 
                // an interface of a device; it does not require or support 
                // configuration and interface selection.
                IUsbDevice wholeUsbDevice = MyUsbDevice as IUsbDevice;
                if (!ReferenceEquals(wholeUsbDevice, null))
                {
                    // This is a "whole" USB device. Before it can be used, 
                    // the desired configuration and interface must be selected.

                    // Select config #1
                    wholeUsbDevice.SetConfiguration(1);

                    // Claim interface #0.
                    wholeUsbDevice.ClaimInterface(0);
                }

                // open read endpoint 1.
                UsbEndpointReader reader = MyUsbDevice.OpenEndpointReader(ReadEndpointID.Ep01);


                byte[] readBuffer = new byte[1024];
                while (ec == ErrorCode.None)
                {
                    int bytesRead;

                    // If the device hasn't sent data in the last 5 seconds,
                    // a timeout error (ec = IoTimedOut) will occur. 
                    ec = reader.Read(readBuffer, 5000, out bytesRead);

                    if (bytesRead == 0) throw new Exception(string.Format("{0}:No more bytes!", ec));
                    Console.WriteLine("{0} bytes read", bytesRead);

                    // Write that output to the console.
                    Console.Write(Encoding.Default.GetString(readBuffer, 0, bytesRead));
                }

                Console.WriteLine("\r\nDone!\r\n");
            }
            catch (Exception ex)
            {
                Console.WriteLine();
                Console.WriteLine((ec != ErrorCode.None ? ec + ":" : String.Empty) + ex.Message);
            }
            finally
            {
                if (MyUsbDevice != null)
                {
                    if (MyUsbDevice.IsOpen)
                    {
                        // If this is a "whole" usb device (libusb-win32, linux libusb-1.0)
                        // it exposes an IUsbDevice interface. If not (WinUSB) the 
                        // 'wholeUsbDevice' variable will be null indicating this is 
                        // an interface of a device; it does not require or support 
                        // configuration and interface selection.
                        IUsbDevice wholeUsbDevice = MyUsbDevice as IUsbDevice;
                        if (!ReferenceEquals(wholeUsbDevice, null))
                        {
                            // Release interface #0.
                            wholeUsbDevice.ReleaseInterface(0);
                        }

                        MyUsbDevice.Close();
                    }
                    MyUsbDevice = null;

                    // Free usb resources
                    UsbDevice.Exit();

                }

                // Wait for user input..
                Console.ReadKey();
            }
        }
    }
}
Example
CopyVB.NET
Imports System
Imports System.Text
Imports LibUsbDotNet
Imports LibUsbDotNet.Main

Namespace Examples
    Friend Class ReadPolling
        Public Shared MyUsbDevice As UsbDevice

        #Region "SET YOUR USB Vendor and Product ID!"

        Public Shared MyUsbFinder As New UsbDeviceFinder(1234, 1)

        #End Region

        Public Shared Sub Main(args As String())
            Dim ec As ErrorCode = ErrorCode.None

            Try
                ' Find and open the usb device.
                MyUsbDevice = UsbDevice.OpenUsbDevice(MyUsbFinder)

                ' If the device is open and ready
                If MyUsbDevice Is Nothing Then
                    Throw New Exception("Device Not Found.")
                End If

                ' If this is a "whole" usb device (libusb-win32, linux libusb-1.0)
                ' it exposes an IUsbDevice interface. If not (WinUSB) the 
                ' 'wholeUsbDevice' variable will be null indicating this is 
                ' an interface of a device; it does not require or support 
                ' configuration and interface selection.
                Dim wholeUsbDevice As IUsbDevice = TryCast(MyUsbDevice, IUsbDevice)
                If Not ReferenceEquals(wholeUsbDevice, Nothing) Then
                    ' This is a "whole" USB device. Before it can be used, 
                    ' the desired configuration and interface must be selected.


                    ' Select config #1
                    wholeUsbDevice.SetConfiguration(1)

                    ' Claim interface #0.
                    wholeUsbDevice.ClaimInterface(0)
                End If

                ' open read endpoint 1.
                Dim reader As UsbEndpointReader = MyUsbDevice.OpenEndpointReader(ReadEndpointID.Ep01)


                Dim readBuffer As Byte() = New Byte(1023) {}
                While ec = ErrorCode.None
                    Dim bytesRead As Integer

                    ' If the device hasn't sent data in the last 5 seconds,
                    ' a timeout error (ec = IoTimedOut) will occur. 
                    ec = reader.Read(readBuffer, 5000, bytesRead)

                    If bytesRead = 0 Then
                        Throw New Exception(String.Format("{0}:No more bytes!", ec))
                    End If
                    Console.WriteLine("{0} bytes read", bytesRead)

                    ' Write that output to the console.
                    Console.Write(Encoding.[Default].GetString(readBuffer, 0, bytesRead))
                End While

                Console.WriteLine(vbCr & vbLf & "Done!" & vbCr & vbLf)
            Catch ex As Exception
                Console.WriteLine()
                Console.WriteLine((If(ec <> ErrorCode.None, ec & ":", [String].Empty)) & ex.Message)
            Finally
                If MyUsbDevice IsNot Nothing Then
                    If MyUsbDevice.IsOpen Then
                        ' If this is a "whole" usb device (libusb-win32, linux libusb-1.0)
                        ' it exposes an IUsbDevice interface. If not (WinUSB) the 
                        ' 'wholeUsbDevice' variable will be null indicating this is 
                        ' an interface of a device; it does not require or support 
                        ' configuration and interface selection.
                        Dim wholeUsbDevice As IUsbDevice = TryCast(MyUsbDevice, IUsbDevice)
                        If Not ReferenceEquals(wholeUsbDevice, Nothing) Then
                            ' Release interface #0.
                            wholeUsbDevice.ReleaseInterface(0)
                        End If

                        MyUsbDevice.Close()
                    End If
                    MyUsbDevice = Nothing

                    ' Free usb resources


                    UsbDevice.[Exit]()
                End If

                ' Wait for user input..
                Console.ReadKey()
            End Try
        End Sub
    End Class
End Namespace
Compiling the Code
  1. Create a new console application in your favorite designer.

  2. Verify your project references:

    • System.dll

    • LibUsbDotNet.dll

  3. Add/edit the main class. Copy/Paste code from one of the examples above.

Note: Example usb device firmware is located in the [InstallDirectory]\Benchmark\Firmware\[Manufacturer] directory.