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EHS8 and GPS receiver

Tutorial, October 14, 2016 - 4:01pm, 1521 views

This article is for those working with EHS8 and want to make sure GPS is always ON.

One of the power saving features of EHS8 switches OFF the GPS after 1.5 min with no FIX

Here is the small JAVA MidLet (code snippet) which you can install to run in the background which will check for the status of your GPS receiver and keep tit running. The Midlet can run in parallel to your java code, or even if you do not use java at all.

This shows how great java is and how you can move some parts of the non-time critical code from your microcontroler to the Java Virtual Maschine.

***************************************************************************

import javax.microedition.io.CommConnection;

import javax.microedition.io.Connector;

import javax.microedition.midlet.MIDlet;

import javax.microedition.midlet.MIDletStateChangeException;

import java.io.*;

import com.cinterion.io.*;

public class GPSService extends MIDlet {

CommConnection  commConn;

InputStream     inStream;

OutputStream    outStream;

private ATCommand m_Cmd;

    private Listener m_Listener = new Listener();

    

    static int TIME_WAIT = 10000; //time to wait at StartUP

    static int TIME_PULL = 500; //time to wait in between Query

    static boolean Debug=true; //Switch for Debug PrintOUt

    static String strQueryGPS = "AT^SGPSC?\r\n";

    static String strLookFor="^SGPSC: \"Engine\",\"0\"\r\n";  //AT Command Response Line to look for to "AT^SGPSC?"

    static String strStartGPS="AT^SGPSC=\"Engine\",\"3\"\r\n";

        

    /**

     * Implementation of ATCommandListener to receive asynchronous events

     */

     private class Listener implements ATCommandListener {

     

         public void ATEvent(String Event) {

        if(Debug)

        System.out.println("ATEvent " + Event);

         }

         public void RINGChanged(boolean SignalState) {

        if(Debug)

        System.out.println("RINGChanged " + SignalState);

         }

         public void DCDChanged(boolean SignalState) {

        if(Debug)

        System.out.println("DCDChanged " + SignalState);

         }

         public void DSRChanged(boolean SignalState) {

        if(Debug)

        System.out.println("DSRChanged " + SignalState);

         }

         public void CONNChanged(boolean SignalState) {

        if(Debug)

        System.out.println("CONNChanged " + SignalState);

         }

      }

     

     /**

      * Implementation of ATCommandResponseListener to receive asynchronous responses

      */

     /*

      private class RspListener implements ATCommandResponseListener {

          public void ATResponse(String Response) {

         if(Debug){

             System.out.println("Received asynchronous response:");

             System.out.println(Response);

         }//end if

          }//End Function

      }//End Class

*/

      

public GPSService() {

// TODO Auto-generated constructor stub

if(Debug){

System.out.println("GPSService: Constructor");

   System.out.println("Available COM-Ports: " + System.getProperty("microedition.commports"));

}

   try {

     

     String strCOM = "comm:COM0;blocking=off;baudrate=115200";

     commConn = (CommConnection)Connector.open(strCOM);

     if(Debug){

     System.out.println("CommConnection(" + strCOM + ") opened");

     System.out.println("Real baud rate: " + commConn.getBaudRate());

     }

     inStream  = commConn.openInputStream();

     outStream = commConn.openOutputStream();

     if(Debug)

     System.out.println("InputStream and OutputStream opened");

     

     

   } catch(IOException e) {

    if(Debug)

    System.out.println(e);

    notifyDestroyed();

   }

    

   try {

            m_Cmd = new ATCommand(false);

            m_Cmd.addListener(m_Listener);

        } catch (Exception e) {

        if(Debug)

        System.out.println(e);

        }

   

   

}

protected void destroyApp(boolean unconditional)

throws MIDletStateChangeException {

// TODO Auto-generated method stub

if(Debug)

System.out.println("GPSService: destroyApp(" + unconditional + ")");

try {

if(Debug)

outStream.write(("GPSService: destroyApp(" + unconditional + ")").getBytes());

   inStream.close();

   outStream.close();

   commConn.close();

   if(Debug)

    System.out.println("Streams and connection closed");  

} catch(IOException e) {

if(Debug)

System.out.println(e);

}

try {

            m_Cmd.release();

        } catch (IOException e) {

        if(Debug)

        System.out.println(e);

        }

notifyDestroyed();

}

protected void pauseApp() {

// TODO Auto-generated method stub

if(Debug)

System.out.println("GPSService: pauseApp()");

}

protected void startApp() throws MIDletStateChangeException {

// TODO Auto-generated method stub

if(Debug){

System.out.println("GPSService: startApp");

   System.out.println("Looping back received data, leave with 'Q'...");

}

   try {

   

    if(Debug)

    outStream.write(("GPSService: startApp").getBytes());

   

   

    //*************************************************

    //Fist give the modem Time for it's Configuration 

    //Time is defined by TIME_WAIT

    //Pause for Receiving 

        Thread.sleep(TIME_WAIT);

       

        

        if(Debug)

    outStream.write(("GPSService: StartUP TimeOut elapsed").getBytes());

   

   

    //**************************************

//Handle User input Serial Com 

   //handle is as a String

    //String strInput="";

    //int ch = -1;

    //while(ch != 'Q') {

    while(true) {

    //ch = inStream.read();

    //*********************************

  //Query if GPS Engine is running

  String strResponse1 = m_Cmd.send(strQueryGPS);

   

  //****************************************

  //Query if GPS Engine is not running

  //if(Response.startsWith(strLookFor)){

  if(strResponse1.indexOf(strLookFor)>0){

  //if(Debug) outStream.write(("GPS Engine Off\r\n").getBytes());

  //****************************

  //Start GPS Engine

  strResponse1 = m_Cmd.send(strStartGPS);

   

  if(Debug){

  if(strResponse1.indexOf("ERROR")>0){

  outStream.write(("ERROR Starting GPS Engine\r\n").getBytes());

  }

  }//End If Debug

   

  }

  //*************************

  //Timeout in between Query

  Thread.sleep(TIME_PULL);

   

        /*

        //Char with int 10  == Line feed 

       if (ch != 10) {

        strInput = strInput +(char)ch;

        //System.out.print((char)ch1);

         

       }else{

        if(Debug)

        System.out.println("String finished");

        if (strInput!=""){

        if(Debug){

        //System.out.print(strInput);

        //Test output to serial com

        outStream.write(("Input received : " + strInput).getBytes());

        System.out.println("GPSService: sending: " + strInput);

        }

        try {

        if(Debug)

        System.out.println("Sending synchronous ");

        strInput= strInput +13;

        if(Debug)

        System.out.println(strInput);

        String Response = m_Cmd.send(strInput);

        if(Debug){

        System.out.println("Received synchronous response:");

        System.out.println(Response);

        outStream.write(("--------------\n").getBytes());

        outStream.write(Response.getBytes());

        outStream.write(("--------------\n").getBytes());

        }

         

         

         

        }catch (Exception e) {

        if(Debug)

                   System.out.println(e);

            }

       

       

        strInput="";

       

        }//end if

       }//End if 

       */

     }//End while

   /*

   }catch(IOException e) {

    System.out.println(e);

   */

   }catch  (Exception e)

        {

    System.out.println(e);

        }

   System.out.println();

   destroyApp(true);

}

}

**********************************************************************

Basic config rules are at the beggining of the code.

Code provided as example. No support on it :)  

Special thanks to Sasha!  

antero.markkula@enkom.fi's picture
antero.markkula...

Hi!

Good work! The GPS off has been an annoying feature for some customers.
Now  they can get rid of it quite easily.
This idea really shows the power of Java.

Best Regards, Antero

Antero Markkula
Communication and Mechatronics

Enkom Active Oy – www.enkom-active.fi
Upseerinkatu 3 A, 02600 Espoo, Finland
Mobile: +358 400 411368
Office: +358 10 204 0000
Fax: +358 10 204 0010
E-mail: antero.markkula@enkom-active.fi

Zeljko