Serial Port Already in Use Error

Looking for any advice that helps me avoid having to restripe my main harddrive, which will be too difficult to do right now. Getting "Serial Port Already in Use" error

Running MacBook Pro OSX 10.6.8 Tried Arduino 1.0 and 023 Tried Arduino UNO and Diecimila, both work on other computers. Tried multiple USB cables. Tried reboots. No other programs or hardware running on machine. Tried turning off Airport to be discrete from internet access. Tried lsof | grep usbmodem in Terminal with UNO, then Diecimila attached. Returns nothing. Tried looking for a txrx.jar file in Java Extensions. None found. Tried uninstalling drivers, running UNO without drivers, reinstalling drivers. No luck. Tried Repair Disk in disk utility. Disk Utility does not detect the need to repair. Repaired permissions in disk utility. Extensive repair was performed but did not solve problem.

Thanks, Colleen

Uno and Diecimila will appear with different serial port names.

Which port are you selecting in the IDE?

Use “screen” to connect to the serial port and see if it complains too. (ctrl-a ctrl-\ to exit, or just close the terminal window.)

Hi James, thanks for responding. I was reading some of your other posts.

UNO uses dev/tty.usbmodemfd121 and /dev/cu.usbmodemfd121 DIECIMILA uses /dev/tty.usbserial-A9003VR9 and /dev/cu.usbserial-A9003VR9

If I'm doing it correctly, I typed "screen" in Terminal and got this - Screen version 4.00.03 (FAU) 23-Oct-06. I let it sit in the background as I do my Arduino tests. Screen returns nothing. No activity, no complaints.

I'll be around all weekend working on this. Have to teach it on Tuesday!

"screen /dev/tty.usbmodemfd121"

You can also specify a baud rate after the device name, but it really doesn't matter. All you are doing is trying to use something other than avrdude to open the serial port.

For the Diecimila, you might try re-installing the FTDI drivers.

When I do that I get this: -bash: screen /dev/tty.usbmodemfd121: No such file or directory

you get that error when your Uno is connected?

what does this show: ls -l /dev/tty.usbmodemfd121

You get that error when your Uno is connected? That is correct.

what does this show: ls -l /dev/tty.usbmodemfd121

I get: crw-rw-rw- 1 root wheel 11, 14 Jan 20 22:55 /dev/tty.usbmodemfd121 Colleen-Ludwigs-MacBook-Pro:~ ludwigc$

Run the screen command again, this time without the quotation marks.

e.g: screen /dev/tty.usbmodemfd121

It goes by quickly and I can't copy/paste but it says something like:

Cannot open line for ‘/dev/tty.usbmodemfd121’ for R/W: Resource busy Sorry, could not find a PTY.