Serial Read on Android API 17 about usbserial HOT 13 CLOSED

Hi @fabio978
@BenLeggieroNCR is right. Some devices can split data. You can buffer it till everything is receive, this is what I've usuallly done myself.

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There were problems with the Android USB api below 4.3 but my code was using 4.2 as threshold. I've updated the SerialPortExample with a new UsbSerial.jar. Could you give it a try?

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I had updated my USBSerial.jar earlier to the latest and that didnt have any affect. Still can't get Serial Read to work

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Mmm I will try to add a way to force synchronous transmissions programatically as soon as possible.

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If this is related, I am also having issues with a separate thread issuing a write command. I ended up hacking a solution together using Java's synchonized block and Thread#sleep(long)

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No it shouldn't. Write operations can be performed from multiple threads

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Hi, thank you for this library, is the only one i could make it working between Android and Arduino.
I am on Android 4.2.2 (API 17), and i have problems while receiving (length doesn't matter) strings from Arduino: sometimes they are empty or incomplete/splitted. If I use a serial monitor app on the same Android device, it always correctly read the strings.
In the past i was used to "wait" for a string terminator char before using it, because i was getting char by char. Am i doing something wrong?

Thank you very much

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@fabio978 I experienced the same thing. This is because certain USB-Serial devices send the data character-by-character instead of as a whole string. I got around it by waiting 100ms after every read, to give UsbSerial time to buffer up all the data so I can receive it in one chunk.

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Thanks for your reply. Should i implement a buffer on my app, then?

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I would do it in that way appending any received character to a StringBuffer till it meets your criteria.

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In the long run I would like to add a more synchronous way to allow both ways of receiving data.

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Hey brother, we have same problem, i can write but i dont have any response from what i write, is there any problem what i code?

public void sendCommandData(String id ,UsbSerialDevice usbSerialDevice,String data)
  {
      this.id = id;
      usbSerialDevice.write(data.getBytes());
      usbSerialDevice.read(deviceRespond);
  }

  public void openDevice(UsbDevice device, int setBaundrate, SerialCommuncationListener.OpenDeviceListener listener)
  {
      UsbSerialDevice serialDevice;
      UsbDeviceConnection connection = usbManager.openDevice(device);
      serialDevice = UsbSerialDevice.createUsbSerialDevice(device, connection);
      if (serialDevice != null) {
          if (serialDevice.open()) {
              serialDevice.setBaudRate(setBaundrate);
              serialDevice.setDataBits(UsbSerialInterface.DATA_BITS_8);
              serialDevice.setStopBits(UsbSerialInterface.STOP_BITS_1);
              serialDevice.setParity(UsbSerialInterface.PARITY_NONE);
              serialDevice.setFlowControl(UsbSerialInterface.FLOW_CONTROL_OFF);
              serialDevice.read(deviceRespond);
              listener.onConnectDeviceSuccess(serialDevice);
          } else {
              listener.onConnectDeviceFailure("Device can not open");
          }
      } else {
          listener.onConnectDeviceFailure("Serial is null");
      }
  }

  public void disconnect(UsbSerialDevice serialDevice)
  {
      if(serialDevice != null)
      serialDevice.close();
  }

  private UsbSerialInterface.UsbReadCallback deviceRespond = new UsbSerialInterface.UsbReadCallback() {
      @Override
      public void onReceivedData(byte[] arg0)
      {
          Toast.makeText(mContext,"RESPONSE TERMINAL: "+arg0,Toast.LENGTH_LONG ).show();
          mCallback.onDeviceResponse(id,arg0);
      }

  };

UsbSerialInterface.UsbReadCallback deviceRespond no response at all
@felHR85

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Yes, I want to read data from USB whenever a USB device gives a flag. are there any methods to do so.?

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