private static UsbStdSetupPacket GetPartialDescriptorRequest()
{
// request 8 bytes initially, to find out the length of the descriptor
var package = new UsbStdSetupPacket {
bmRequestType = (byte)(UsbConstants.UsbSetupDataStageIn |
UsbConstants.UsbReqRecipientDevice |
UsbConstants.UsbReqTypeStandard),
bRequest = 6, // GET_DESCRIPTOR
wLength = 8,
wIndex = 0,
wValue = 1 << 8 // Device
};
return(package);
}
private string GetStringDescriptor(ushort stringDescriptorIndex)
{
var packet = new UsbStdSetupPacket
{
bmRequestType = 0x80,
bRequest = 6, // GET_DESCRIPTOR
wValue = (ushort)((3 << 8) + stringDescriptorIndex), // 3 => STRING
wIndex = 0x0409,
wLength = 256
};
var buffer = _usbControlPipe.ControlTransferIn(packet.bmRequestType, packet.bRequest, packet.wValue, packet.wIndex, packet.wLength);
// this is required due to an issue in WinUSB.NET 1.0.3;
// should be fixed in WinUSB.NET 2.0.0
var realLength = Math.Max(Math.Min(buffer[0], buffer.Length) - 2, 0);
return(Encoding.Unicode.GetString(buffer, 2, realLength));
}
