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POread from commport doesn't return full result on java
 

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    <p>I was trying to read from a com port using the rxtx API. The com port was connected to a micro controller, so that every time I pressed a button on the micro controller board, it will return me a series of byte number counting from 0x01 to 0xff. I wanted to display these number on my java console, but it seemed to be able to read up to 0x40. All the other byte numbers after seemed to get lost. I was pretty sure the microcontroller was working well, since I tested in another terminal program which then gave out the correct result. So I suspect there is something wrong with my inputstream. Is there anyone who could kindly help me locate the problem? Following is my java code, which is a typical serial com port read example code I found from google.</p> <pre><code>import gnu.io.CommPortIdentifier; import gnu.io.PortInUseException; import gnu.io.SerialPort; import gnu.io.SerialPortEvent; import gnu.io.SerialPortEventListener; import gnu.io.UnsupportedCommOperationException; import java.io.*; import java.util.*; public class SimpleRead implements Runnable, SerialPortEventListener { static CommPortIdentifier portId; static Enumeration portList; InputStream inputStream; SerialPort serialPort; Thread readThread; public static void main(String[] args) { portList = CommPortIdentifier.getPortIdentifiers(); while (portList.hasMoreElements()) { portId = (CommPortIdentifier) portList.nextElement(); if (portId.getPortType() == CommPortIdentifier.PORT_SERIAL) { if (portId.getName().equals("COM7")) { // if (portId.getName().equals("/dev/term/a")) { SimpleRead reader = new SimpleRead(); } } } } public SimpleRead() { try { serialPort = (SerialPort) portId.open(this.getClass().getName(), 2000); } catch (PortInUseException e) {System.out.println(e);} try { inputStream = serialPort.getInputStream(); } catch (IOException e) {System.out.println(e);} try { serialPort.addEventListener(this); } catch (TooManyListenersException e) {System.out.println(e);} serialPort.notifyOnDataAvailable(true); try { serialPort.setSerialPortParams(115200, SerialPort.DATABITS_8, SerialPort.STOPBITS_1, SerialPort.PARITY_NONE); } catch (UnsupportedCommOperationException e) {System.out.println(e);} readThread = new Thread(this); readThread.start(); } public void run() { try { //System.out.println("1"); Thread.sleep(20000); } catch (InterruptedException e) {System.out.println(e);} } public void serialEvent(SerialPortEvent event) { switch(event.getEventType()) { case SerialPortEvent.BI: case SerialPortEvent.OE: case SerialPortEvent.FE: case SerialPortEvent.PE: case SerialPortEvent.CD: case SerialPortEvent.CTS: case SerialPortEvent.DSR: case SerialPortEvent.RI: case SerialPortEvent.OUTPUT_BUFFER_EMPTY: break; case SerialPortEvent.DATA_AVAILABLE: byte[] readBuffer = new byte[4049]; try { while (inputStream.available() &gt; 0) { int numBytes = inputStream.read(readBuffer); } for(Byte bytenum: readBuffer)System.out.print(Integer.toHexString(bytenum)+" "); } catch (IOException e) {System.out.println(e);} break; } if (serialPort != null) { try { // close the i/o streams. inputStream.close(); } catch (IOException ex) { System.out.println(ex); } // Close the port. serialPort.close(); } } </code></pre> <p>}</p> <p>And Here is the partial result ( note that byte number after 40 is not read successfully) 1 2 3 4 5 6 7 8 9 a b c d e f 10 11 12 13 14 15 16 17 18 19 1a 1b 1c 1d 1e 1f 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f 40 0 0 0 0 0 0 0</p> <p>Thanks</p>
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