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Message:
javax.comm using parallel port
Posted by mahmoud on October 28, 2001 at 9:13 AM
> /* Currently, I am working on controlling IBM Parallel Port using */
> /* Java Communication API. And i faced a few problems and wish */
> /* can get help as soon as possible. All helps are highly appreciated. */ > DOSone.writeByte(0x90); ------- Statement 1
> When the LED attached with parallel port are connected with the computer, Data Pin 3,4,5,6,7,8
> are lighted. Although i tried to change to different values, same results are obtained.
> May I know why this happened? and any solution? > System.out.println("You have come here."); ------Statement 2
> After the LED is lighted, the Java program does not return back to DOS mode and print out
> the above sentence. Can i make hypotheses that Java are platform independent, that's why
> there is no way to return to Windows Dos mode? Or any solution available? > The source code is obtained from http://www.geocrawler.com/archives/3/196/1999/8/50/2586646/ and some slight modification is done
> /* modified by cclee */
> /* date: 23.08.2001 */
> /* Platform : Windows 98 & JDK1.2 */ > import javax.comm.*;
> import javax.comm.ParallelPort;
> import java.util.*;
> import java.lang.*;
> import java.io.*; > public class TestApp
> {
> static CommPortIdentifier CPIone;
> static Enumeration Eone;
> static ParallelPort Pone;
> static OutputStream OSone;
> static DataOutputStream DOSone;
> public static void main (String arg[])
> {
> Eone=CommPortIdentifier.getPortIdentifiers();
> while(Eone.hasMoreElements())
> {
> CPIone=(CommPortIdentifier)Eone.nextElement();
> if((CPIone.getPortType()==CommPortIdentifier.PORT_PARALLEL)&&((CPIone.getName()).compareTo("LPT1")==0))
> {
> try
> {
> Pone=(ParallelPort)CPIone.open("TestApp",3000);
> }catch(PortInUseException e){}
> System.out.println(CPIone.getCurrentOwner());
>
> System.out.println(Pone.getMode());
> System.out.println(CPIone.getPortType());
> try
> {
> Pone.setMode(1);
> }catch(UnsupportedCommOperationException e)
> {
> System.out.println("Unsupported byte mode.");
> }
> System.out.println("unidirectional");
> }
> }
> try
> {
> OSone=Pone.getOutputStream();
> DOSone = new DataOutputStream(OSone);
>
> /*where to send the data to the printer port */
> DOSone.writeByte(0x90); ------- Statement 1
> System.out.println("You have come here."); ------Statement 2
> }
> catch(IOException e)
> {
> System.out.println("You are in IOexception");
> e.printStackTrace();
> }
> }
> }
>
> Below are the circuit that i used for my testing
> >
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