Android Usb Host Receive Data

Question

I try to reading data from my evalboard. It is Stellaris EKK-LM4F232 Evalutaion Kit. It has five buttons. I push a button on board and send data to my android device. For example, i push one times, and board send to 1, and second times send to 2.... I receive the first value (it mean 1) from android device when i push the button first time. But when i push the button again, i can't receive any other values like 2 ,3 ,4 ,... . Here is my code for reading. It read continuously when it is start. Can you help me?

public void startDataRecieve() {
    new Thread(new Runnable() {

        @Override
        public void run() {

            UsbEndpoint endpoint = null;

            for (int i = 0; i < intf.getEndpointCount(); i++) {
                if (intf.getEndpoint(i).getDirection() == UsbConstants.USB_DIR_IN) {
                    endpoint = intf.getEndpoint(i);
                    break;
                }
            }
            UsbRequest request = new UsbRequest(); // create an URB
            boolean initilzed = request.initialize(connection, endpoint);

            if (!initilzed) {
                Log.e("USB CONNECTION FAILED", "Request initialization failed for reading");
                return;
            }
            while (true) {
                int bufferMaxLength = endpoint.getMaxPacketSize();
                ByteBuffer buffer = ByteBuffer.allocate(bufferMaxLength);


                if (request.queue(buffer, bufferMaxLength) == true) {
                    if (connection.requestWait() == request) {
                        String result = new String(buffer.array());
                            Log.i("GELEN DATA : ", result);
                            listener.readData(result);
                    }
                }
            }

        }
    }).start();
}

If you can't understand very well the same question is here asked by one Android bulkTransfer return -1 when read data but there is really some data in the buffer

After the discusstion with @Mike Ortiz I put all my code in here. When I click the buttonSend android device send "START" command to device then reading start. When i send to android device to first value i can get it but after first value i don't get any value from usb device. I am sure the usb device sends the values.

public class MainActivity extends Activity implements Runnable {

private static final String TAG = "MAIN ACTIVITY TEST ";

private Button buttonConnect;
private Button butonSend;
private Button buttonDisconnect;
private TextView textViewResult;
private UsbDevice device;

private Thread readThread;
private UsbManager usbManager;
private UsbDeviceConnection connection;
private UsbInterface usbInterface;
private UsbEndpoint usbEndpointIn;
private UsbEndpoint usbEndpointOut;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    initView();

    PendingIntent mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
    IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
    registerReceiver(usbReceiver, filter);

    usbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
    HashMap<String, UsbDevice> deviceList = usbManager.getDeviceList();
    Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();

    while (deviceIterator.hasNext()) {
        UsbDevice device = deviceIterator.next();

        if (device.getVendorId() == 7358 && device.getProductId() == 3) {
            this.device = device;
            usbManager.requestPermission(device, mPermissionIntent);
            break;
        }
    }

    butonSend.setOnClickListener(new OnClickListener() {


        @Override
        public void onClick(View v) {
            usbInterface = device.getInterface(0);
            connection = usbManager.openDevice(device);
            connection.claimInterface(usbInterface, false);

            for (int i = 0; i < usbInterface.getEndpointCount(); i++) {
                UsbEndpoint end = usbInterface.getEndpoint(i);
                if (end.getDirection() == UsbConstants.USB_DIR_IN) {
                    usbEndpointIn = end;

                } else {
                    usbEndpointOut = end;
                }
            }

            //SEND START COMMAND TO  THE USB DEVICE; 
            int result = connection.bulkTransfer(usbEndpointOut, "START".getBytes(), "START".getBytes().length, 1000);
            Log.e("SEND RESULT", result + "");


            //START READING in run method
            readThread = new Thread(MainActivity.this);
            readThread.start();




        }
    });

    buttonDisconnect.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            mRunning = false;
            //readThread.stop();
            connection.releaseInterface(usbInterface);
            connection.close();
            Log.e(TAG, "Connection CLosed.");

        }
    });
}

private static final String ACTION_USB_PERMISSION = "com.android.example.USB_PERMISSION";
private final BroadcastReceiver usbReceiver = new BroadcastReceiver() {

    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (ACTION_USB_PERMISSION.equals(action)) {
            synchronized (this) {
                UsbDevice device = (UsbDevice) intent.getParcelableExtra(UsbManager.EXTRA_DEVICE);

                if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                    if (device != null) {
                        Toast.makeText(MainActivity.this, "Cihaza izin verildi", Toast.LENGTH_LONG).show();
                    }
                } else {
                    Toast.makeText(MainActivity.this, "Cihaza izin verilmedi.", Toast.LENGTH_LONG).show();
                    Log.d(TAG, "permission denied for device " + device);
                }
            }
        }
    }
};

private boolean mRunning;

private void initView() {
    butonSend = (Button) findViewById(R.id.buttonSend);
    buttonConnect = (Button) findViewById(R.id.buttonConnect);
    textViewResult = (TextView) findViewById(R.id.textViewResult);
    buttonDisconnect = (Button) findViewById(R.id.buttonDisconnect);
}

@Override
public void run() {
    mRunning = true; 

    //READ VALUE UNTIL DISCONNECT
    while (mRunning) {

        byte[] bytes = new byte[usbEndpointIn.getMaxPacketSize()];
        int result = connection.bulkTransfer(usbEndpointIn, bytes, bytes.length, 1000);
        if(result > 0)
        Log.e("RESULT : " + result, "  VALUE : " + new String(bytes));


    }
    Log.d("Thread", "STOPPPED");

} 

}

Answer 1

Which condition fails in your loop? (request.queue(buffer, bufferMaxLength) == true) or (connection.requestWait() == request)? If it's the second, I might suggest using .equals() instead of the reference comparison ==.

Have you tried to use bulk transfer instead of requests?

private UsbManager mManager; 
private UsbDevice  mDevice;
private UsbDeviceConnection mDeviceConnection;
private UsbInterface mInterface;
private UsbEndpoint mEndpointIn;   

public void run() {
    while (mEndpointIn != null && mDeviceConnection != null) {
        byte[] recordIn = new byte[mEndpointIn.getMaxPacketSize()];
        int receivedLength = mDeviceConnection.bulkTransfer(mEndpointIn, recordIn,
                                                       recordIn.length, mTimeout);
        if (receivedLength > -1) passDataToListener(recordIn);
    }
}

public void initializeCommunication(Context context) throws UsbDeviceException {

    mInterface = findHidInterface();

    if (mManager != null && mDevice != null && mInterface != null) {
        mDeviceConnection = mManager.openDevice(mDevice);

        if (mDeviceConnection != null) {
            if (mDeviceConnection.claimInterface(mInterface, true)) {
                UsbEndpoint usbEndpointOut = null;
                UsbEndpoint usbEndpointIn = null;

                //
                // Look for Interrupt endpoints
                //
                for (int i = 0; i < mInterface.getEndpointCount(); i++) {
                    UsbEndpoint usbEndpoint = mInterface.getEndpoint(i);

                    if (usbEndpoint.getType() == UsbConstants.USB_ENDPOINT_XFER_INT) {
                        if (usbEndpoint.getDirection() == UsbConstants.USB_DIR_OUT) {
                            usbEndpointOut = usbEndpoint;

                        } else {
                            usbEndpointIn = usbEndpoint;
                        }
                    }
                }

                if (usbEndpointOut == null || usbEndpointIn == null) {
                    Log.w(DEBUG, "No USB endpoints found.");
                }

                mEndpointOut = usbEndpointOut;
                mEndpointIn = usbEndpointIn;

            } else {
                mDeviceConnection.close();
                Log.w(DEBUG, "USB claim interface failed.");
            }
        } else {
            Log.w(DEBUG, "USB open device failed.");
        }
    } else {
        Log.w(DEBUG, "Some essential USB variables were null.");
    }
}

/**
 * Find the HID interface.
 * 
 * @return
 *      Return the HID interface if found, otherwise null.
 */
private UsbInterface findHidInterface() {
    if (mDevice != null) {
        final int interfaceCount = mDevice.getInterfaceCount();

        for (int interfaceIndex = 0; interfaceIndex < interfaceCount; interfaceIndex++) {
            UsbInterface usbInterface = mDevice.getInterface(interfaceIndex);

            //
            // Can add UsbInterface.getInterfaceSubclass() and 
            // UsbInterface.getInterfaceProtocol() for more specifics.
            //

            if (usbInterface.getInterfaceClass() == UsbConstants.USB_CLASS_HID) {
                return usbInterface;
            }
        }

        Log.w(DEBUG, "HID interface not found.");
    }

    return null;
}