Serial port already in use?

Forum 2005-2010 (read only) Hardware Troubleshooting
1

I've been trying (unsucessfully) to get my Arduino to talk to Processing, or rather to get Processing to listen to my serial port. In that process, I seem to have mangled something rather badly: no matter what I attempt, I always get a "processing.app.SerialException: Serial port '/dev/tty.usbserial-A4001LgE' already in use. Try quiting any programs that may be using it."

This is after a fresh reboot. I have not opened Processing yet, just the Arduino program to load code or listen to the serial port. Using "screen /dev/tty.usbserial-A4001LgE 9600" I can see the stream from the Arduino without any error...

Is this the result of something I did to install the RXTX libraries for Processing? Has anyone ever seen this before? It seems like the Java libraries are messed up rather than the serial port actually being in use...

Thanks for reading!
-brett

2

Close the Arduino IDE!

That is the program that is causing the serial port to be "busy"

3

But I'm using the IDE to push code onto the Arduino, which is when I get this error. I'm not using Processing and it isn't even open (which is why I'm wondering how it shows up in the error message...)

4

It probably doesn't have to do with Processing. The processing.app.SerialException you see in the error message is because Arduino is built on Processing's source code. Have you installed anything else that might use serial ports, like applications for monitoring bluetooth devices or syncing PDA's, etc?

5

Not recently. It was working until yesterday when I was trying to get Processing to properly read the serial port. This error occurs even after a fresh restart with no other application activated. And Screen still works, so the OS doesn't think the serial port is active.

6

I'd search for other copies of the RXTX library (e.g. in your Java extensions folder). It should be files with RXTX or comm.jar in the name.

7

"Other" Copies?

So I removed the copy of RXTXcomm.jar from the java extensions library - the one that I placed there as part of the installation for Processing (http://rxtx.qbang.org/wiki/index.php/Installation_on_MacOS_X)

Now it works! I don't understand it, but whatever!

Thanks! Muchas thanks!

-brett

8

You shouldn't need to manually install those files in that folder for Processing. Processing comes with versions of RXTX and configures itself so your sketches can find them.

9

Yup, I guess I know that now :slight_smile: Thanks again for your suggestions, it is working well now and I installed it without hitch on a second computer. Let the fun begin!
-brett