TINIm400 module and timed reading

[Sofiene Hammad]

Hi,
I'm creating this thread in order to get some details about the applications i'm currently coding.

I have to create a system based on TINI module which acqauires datas from a satellite sensor, gets it y serial comm, to the TINI, which sends it over Ethernet to a computer.
At the moment, I can read by RS232, send over Ethernet. So overally it works fine. However I still have to follow some requirements :
-I have to read and send every seconds.
-Any datas that has not changed since the previous one must not be sent.
-Managing threads.

here is the code :

import javax.comm.*;
import java.io.*;
import java.net.*;
import java.lang.*;
import com.dalsemi.tininet.*;
import com.dalsemi.system.*;
 
class SerialToEthernet extends Thread {
	// Utilisation d'un buffer de 1024 pour le transfert de données
	private static final int INPUT_BUF_LEN = 1024;
	// Serial port and associated streams
	private SerialPort sp;
	private InputStream spin;
	private OutputStream spout;
	// Socket and associated streams
	private Socket s;
	private InputStream sin;
	private OutputStream sout;
	
	// commande à taper pour éxecuter le programme : java SerialToEthernet.tini 192.168.100.3 le port est déjà passé en argument dans le programeme
	private SerialToEthernet(String server)
	throws Exception {
	
		// Creation et initialisation du port serie
		sp = (SerialPort)
		
		// Ouverture du port serie
		CommPortIdentifier.getPortIdentifier("serial0").open(
		"SerialToEthernet", 5000);
		
		// RTS
		TINIOS.setRTSCTSFlowControlEnable(0, false);
		
		// 8 data bits, 1 stop bit, pas de parité
		sp.setSerialPortParams(115200, SerialPort.DATABITS_8,
		SerialPort.STOPBITS_1,
		SerialPort.PARITY_NONE);
		
		// Controle de flux
		sp.setFlowControlMode(SerialPort.FLOWCONTROL_RTSCTS_IN |
		SerialPort.FLOWCONTROL_RTSCTS_OUT);
		
		// Initialisation des flux d'entrées et de sorties'
		spin = sp.getInputStream();
		spin = sp.getInputStream();
		spout = sp.getOutputStream();
		
		// Timeout de lecture de 100ms
		sp.enableReceiveTimeout(100);
		
		// Parametrage du seuil de reception et du buffer
		sp.enableReceiveThreshold(INPUT_BUF_LEN);
		
		// Connection au serveur TCP
		s = new Socket(server, 4400);
		sin = s.getInputStream();
		sout = s.getOutputStream();
		
		// Création et lancement d'un thread Serial To Ethernet'
		(new Thread(new SerialReader(this, INPUT_BUF_LEN))).start();
		
		// Lancement du thread de maintenance
		super.start();
    }
	
//l'utilisation de l'élément volatile s'explique ici par le fait, que la variable running peut être accessible par tout les threads.
private volatile boolean running = true;
private int serialTotal = 0;
private int networkTotal = 0;
 
public void run() {
    while (running) {
		try {
			Thread.sleep(1000);
		} catch (InterruptedException ie) {}
		//System.out.println("Bytes received from serial:" + serialTotal);
		//System.out.println("Bytes received from network:" + networkTotal);
}
}
 
private class SerialReader implements Runnable {
private byte[] serBuf;
private Thread maint;
private SerialReader(Thread maint, int size) {
	serBuf = new byte[size];
	this.maint = maint;
}
public void run() {
	while (running) {
		try {
			System.out.println("Lecture des datas sur le port série");
			int count = spin.read(serBuf, 0, serBuf.length);
			//S'il existe encore des données à lire sur le port alors on continue la lecture'
			if (count > 0) {
				System.out.println("Ecriture des datas sur Ethernet");
				sout.write(serBuf, 0, count);
				serialTotal += count;
			}
		} catch (IOException ioe) {
			// Problème de connection avec le serveur
			System.out.println(ioe.getMessage());
			ioe.printStackTrace();
			running = false;
			maint.interrupt();
			break;
		}
	}
}
}
}

I commented the code as much as I can unfortunatly it's in french.

I meet the following problems , I don't see how to time this operation, I thought it was thanks to the setEnableReceiveTimeOut function but it doesn't seem so.

I have to give a clear defintion of my thread management, is the volatile attribute I used for this running variable correct?


Le thanks

regards

[Greg Charles]

Le thanks ... that's cute.

Anyway, do you really need multiple threads for something that should only happen once a second? If not, you could probably use java.lang.Timer to handle the scheduling. If you really need multiple thread, then java.util.concurrent.ScheduledThreadPoolExecutor is probably more appropriate. I've never had to that class myself though.

In any case, it doesn't seem that the actual I/O is causing you any trouble. If you want, I can move this over to our Threads forum, where you might get some better feedback on the concurrency issues.

[Sofiene Hammad]

Hi and thanks for your answer, I will try to use those 2 libraries you just gave me, however I'm not sure if my TINI board can handle those. Yes I maybe forgot to mention that the application must be uploaded on the card. So this is the JVM embedded on the card that runs everything.
About the thread management, I will move it into the right section asap.
Regards

[Rob Spoor]

Sofiene, please don't recreate threads in different forums. We will move this thread for you.

[Sofiene Hammad]

Sorry for that ^_^
I'm kind of in a hurry these days, expiration date comes faster than what I was expecting.