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Topic: Problem interfacing with Java (Read 352 times) previous topic - next topic

waterburner123

Jul 19, 2012, 01:16 pm Last Edit: Jul 19, 2012, 01:27 pm by waterburner123 Reason: 1
I followed the Interfacing with Java tutorial http://www.arduino.cc/playground/Interfacing/Java, but ran into some problems on testing. Currently my Arduino program works fine when I try with manual inputs.

Segment of C Code on Arduino:
Code: [Select]


...

char line[20];
int line_pos = 0;
char action[10];
unsigned long duration;
boolean data_ready = false;

void setup()
{
 Serial.begin(9600);
 delay(1500);
 Serial.println("Ready!");
}

void loop()
{
   char state;
   if(Serial.available()>0)
   {
       delay(20);
       state = Serial.read();
       
       if(state == '!')
       {
         data_ready = true;
         line[line_pos] = state;
         line_pos = 0;
       }
       else
       {
         line[line_pos] = state;
         line_pos = line_pos + 1;
       }
       
       if(data_ready == true)
       {
           split(line);
           Serial.print(action);
           delay(20);
           Serial.print("!");
           delay(20);
           Serial.print(duration);
           delay(20);
           Serial.print("!");
           
           Serial.println("Data has been split");

           if(strcmp(action, "left") == 0)
           {
               Serial.println("Received left");
           }
           else if(strcmp(action, "right") == 0)
           {
               Serial.println("Received rightt");
           }
           else if(strcmp(action, "straight") == 0)
           {
               Serial.println("Received straight");
           }
           
           memset(line, 0, 20);
           data_ready = false;
       }
   }
}  

void split(char input[20])
{
   char *param, *ptr;
   
   param = strtok_r(input, "#", &ptr);
   strncpy(action, param, sizeof(action));
   action[sizeof(action)-1] = '\0';
   
   param = strtok_r(NULL, "!", &ptr);
   duration = strtoul(param, &param, 10);
}

...



When I input "left#123!" I get the following output in the COM which is what I expected. No problems here:

Ready!
left!123!Data has been split
Received left


Now here's my Java code:

Code: [Select]


import java.io.InputStream;
import java.io.OutputStream;
import gnu.io.CommPortIdentifier;
import gnu.io.SerialPort;
import gnu.io.SerialPortEvent;
import gnu.io.SerialPortEventListener;
import java.util.Enumeration;

public class SerialTest implements SerialPortEventListener {
SerialPort serialPort;
       /** The port we're normally going to use. */
private static final String PORT_NAMES[] = {
"/dev/tty.usbserial-A9007UX1", // Mac OS X
"/dev/ttyUSB0", // Linux
"COM3", // Windows
};
/** Buffered input stream from the port */
private InputStream input;
/** The output stream to the port */
private OutputStream output;
/** Milliseconds to block while waiting for port open */
private static final int TIME_OUT = 2000;
/** Default bits per second for COM port. */
private static final int DATA_RATE = 9600;

private String display = "";

public void initialize() {
CommPortIdentifier portId = null;
Enumeration portEnum = CommPortIdentifier.getPortIdentifiers();

// iterate through, looking for the port
while (portEnum.hasMoreElements()) {
CommPortIdentifier currPortId = (CommPortIdentifier) portEnum.nextElement();
for (String portName : PORT_NAMES) {
if (currPortId.getName().equals(portName)) {
portId = currPortId;
break;
}
}
}

if (portId == null) {
System.out.println("Could not find COM port.");
return;
}

try {
// open serial port, and use class name for the appName.
serialPort = (SerialPort) portId.open(this.getClass().getName(),
TIME_OUT);

// set port parameters
serialPort.setSerialPortParams(DATA_RATE,
SerialPort.DATABITS_8,
SerialPort.STOPBITS_1,
SerialPort.PARITY_NONE);

// open the streams
input = serialPort.getInputStream();
output = serialPort.getOutputStream();

// add event listeners
serialPort.addEventListener(this);
serialPort.notifyOnDataAvailable(true);
} catch (Exception e) {
System.err.println(e.toString());
}
}

/**
* This should be called when you stop using the port.
* This will prevent port locking on platforms like Linux.
*/
public synchronized void close() {
if (serialPort != null) {
serialPort.removeEventListener();
serialPort.close();
}
}

/**
* Handle an event on the serial port. Read the data and print it.
*/
public synchronized void serialEvent(SerialPortEvent oEvent) {
if (oEvent.getEventType() == SerialPortEvent.DATA_AVAILABLE) {
try {
int available = input.available();
byte chunk[] = new byte[available];
input.read(chunk, 0, available);

System.out.println(display);

display += (new String(chunk)).trim();
if(display.contains("!"))
{
display = display.substring(0, display.indexOf("!"));

if(display.equals("Ready"))
{
String reply = "left#123!";
byte reply_byte[] = new byte[reply.length()];
reply_byte = reply.getBytes("UTF-16LE");
output.write(reply_byte);
}

display = "";
}

} catch (Exception e) {
System.err.println(e.toString());
}
}
// Ignore all the other eventTypes, but you should consider the other ones.
}

public static void main(String[] args) throws Exception {
SerialTest main = new SerialTest();
main.initialize();
System.out.println("Started");
}
}



Here's what Java code prints out in console:

Rea


l

0

Data
Datahas
Datahasbee
Datahasbeen sp
Datahasbeen split


The serial input doesn't seem to be read fluidly, but in repeating parts. Can anybody help me diagnose the problem and give me a solution?

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