if I flash a Duemilanove using IDE 0021 (with Ubuntu 10.04) I have this Problem:
I connect the Duemilanove to the Linux Box and the PC can receive the data send by Arduino. I reboot the PC with the Duemilanove attached, and the application on the PC can not receive any data because /dev/ttyUSB0 is in use. If I disconnect the Arduino and connect it again, then everything is working as expected. This happens only with Duemilanove, UNO (wich uses /dev/ttyACM=) is working fine.
If I flash the Duemilanove with IDE 0018 (on Windows) the Duemilanove is also working if attached during boot. So it must have to to something with IDE 0021.
Unfortunately I had to finish my project quick, so I used the 0018 IDE to do that. Now I don't have any Duemilanove to examine the problem any further (the Duemilanove is at my client).
I still have a Mega (1280) and "hoped" I could reproduce the same error with that board, but the Mega works perfect, no error.
I try to get a new Duemilanove to examine the problem again.
Unfortunately my project did not work at the clients site, it must be a chance that it works here a couple of times. So even if I flash the Arduino with 0018 IDE my Linux application can not receive Data if the Arduino is connected to the PC at startup. The serious thing is, that when I do
lsof |grep /dev/ttyUSB
the result is nothing.
/dev/ttyUSB0 is present in the file system. I can see the FTDI chip in /dev/serial/by-id and /dev/serial/by-path
also
screen /dev/ttyUSB0
reports "can not exec /dev/ttyUSB0 : No such file or directory. But /dev/ttyUSB0 is present in the file system