android和fpga板之间的通信

Question

我正在尝试将数据从我的Android设备传输到FPGA板。 android设备支持USB主机模式，连接的FPGA板使用RS_232端口。所以我有一个USB-RS232转换器设备（CP210x）用于连接。我按照本页所述对转移进行了编码：http://developer.android.com/guide/topics/connectivity/usb/host.html我的代码是：

public class MainActivity extends Activity
    implements View.OnClickListener, Runnable {

private static final String TAG = "TransferData";

private Button sendB;
private UsbManager mUsbManager;
private UsbDevice mDevice;
private UsbDeviceConnection mConnection;
private UsbEndpoint mEndpointIntr;
private static final char DATA = 'A';
static UsbDevice device;
static int TIMEOUT = 0;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);
    sendB = (Button)findViewById(R.id.send);
    sendB.setOnClickListener(this);

    mUsbManager = (UsbManager)getSystemService(Context.USB_SERVICE);

}

@Override
public void onPause() {
    super.onPause();
}

@Override
public void onResume() {
    super.onResume();

    Intent intent = getIntent();
    Log.d(TAG, "intent: " + intent);
    String action = intent.getAction();

    device = (UsbDevice)intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);
    if (UsbManager.ACTION_USB_DEVICE_ATTACHED.equals(action)) {
        setDevice(device);
    } else if (UsbManager.ACTION_USB_DEVICE_DETACHED.equals(action)) {
        if (mDevice != null && mDevice.equals(device)) {
            setDevice(null);
        }
    }
}

@Override
public void onDestroy() {
    super.onDestroy();
}

private void setDevice(UsbDevice device) {
    Log.d(TAG, "setDevice " + device);
    if (device.getInterfaceCount() != 1) {
        Log.e(TAG, "could not find interface");
        return;
    }
    else Log.w(TAG, "found interface");
    UsbInterface intf = device.getInterface(0);
    // device should have one endpoint
    if (intf.getEndpointCount() == 0) {
        Log.e(TAG, "could not find endpoint");
        return;
    }
    else Log.w(TAG, "found endpoint");
    // endpoint should be of type interrupt

    Log.w("endpoint", "" + intf.getEndpointCount());
    UsbEndpoint ep = intf.getEndpoint(1);
    if (ep.getType() != UsbConstants.USB_ENDPOINT_XFER_BULK) {
        Log.e(TAG, "endpoint is not interrupt type");
        return;
    }
    else Log.w(TAG, "endpoint is interrupt");
    mDevice = device;
    mEndpointIntr = ep;
    if (device != null) {
        UsbDeviceConnection connection = mUsbManager.openDevice(device);
        if (connection != null && connection.claimInterface(intf, true)) {
            Log.d(TAG, "open SUCCESS");
            mConnection = connection;
            Thread thread = new Thread(this);
            thread.start();

        } else {
            Log.d(TAG, "open FAIL");
            mConnection = null;
        }
     }
}

private void sendCommand(char control) {
        if (mConnection != null) {
            byte[] message = new byte[1];
            message[0] = (byte)control;
            // Send command via a control request on endpoint zero
            UsbInterface intf = device.getInterface(0);
            UsbEndpoint endpoint = intf.getEndpoint(1);
            mConnection.claimInterface(intf,true);
            int res =  mConnection.bulkTransfer(endpoint, message, message.length, TIMEOUT);
            Log.w("data sent","result " + res);
        }
}

public void onClick(View v) {
    if (v == sendB) {
        sendCommand(DATA);
    }
}

@Override
public void run() {
    ByteBuffer buffer = ByteBuffer.allocate(1);
    UsbRequest request = new UsbRequest();
    request.initialize(mConnection, mEndpointIntr);
    byte status = -1;
        request.queue(buffer, 1);
        // send poll status command
        sendCommand(DATA);
        // wait for status event
        if (mConnection.requestWait() == request) {
            byte newStatus = buffer.get(0);
            if (newStatus != status) {
                Log.d(TAG, "got status " + newStatus);
                status = newStatus;
            }
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
            }
        } else {
            Log.e(TAG, "requestWait failed, exiting");
        }
}

我在打开设备方面取得了成功，我将结果发送为1.但是没有收到的数据反映为FPGA板。我在做什么wromg？