CODEWITHSUNDEEP
javalinuxserial-portusb
Aditya Ponkshe
Aditya Ponkshe

Reputation: 3890

How do i select correct active serial port in linux?

I am trying to communicate with a microcontroller using java. In windows i simply use "COM4" and my code workes perfectly. In linux i am trying to use "/dev/ttyUSB0". But gives me an error "Could not find serial port".

I used dmesg | grep tty to see active serial port. is this a right method?

how can i solve this issue? I am really new to linux so please explain in simple language

here is my code

Enumeration portIdentifiers = CommPortIdentifier.getPortIdentifiers();

  CommPortIdentifier portId = null; 
  while (portIdentifiers.hasMoreElements())
  {
      CommPortIdentifier pid = (CommPortIdentifier) portIdentifiers.nextElement();
      if(pid.getPortType() == CommPortIdentifier.PORT_SERIAL &&
         pid.getName().equals("/dev/ttyUSB0")) 
      {
          portId = pid;
          break;
      }
  }
  if(portId == null)
  {
      System.err.println("Could not find serial port "); // + wantedPortName);
      System.exit(1);
  }

Upvotes: 0

Views: 1607

Answers (2)

Aditya Ponkshe
Aditya Ponkshe

Reputation: 3890

Apparently java communication API do not have linux implementation http://www.oracle.com/technetwork/java/index-139971.html thats why my code wasn't working.

I installed RXTX library for serial communication and code is working fine now. Thanks nos and Olaf Dietsche for the help and support.

Upvotes: 0

Olaf Dietsche
Olaf Dietsche

Reputation: 74008

lsusb should show you the serial to USB converter 

lsusb | grep -i serial

gives on my system

Bus 001 Device 005: ID 067b:2303 Prolific Technology, Inc. PL2303 Serial Port

and 

ls -l /dev/ttyUSB*

crw-rw---- 1 root dialout 188, 0 Feb 18 10:30 /dev/ttyUSB0

I can then access it with 

cat /dev/ttyUSB0

The user, who needs access to the port, must be in the group dialout or whatever group it is in your system. You can add the user with 

adduser <user-name> dialout

Upvotes: 1

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