I'm using a modified version of Arduino Zero Bootloader. I am trying to write software to automatically detect which USB device the bootloader is currently running on in order to execute bossac.
I have noticed a few unique characteristics when using "lsusb -v". Things like "bDeviceClass" is always 2. and "bDeviceSubClass" is always 0; However, I do not feel confident in using these traits to identify the bootloader. Is there any clear indication of bootloader so I can find the correct ttyACM#?
The only things you have at your disposal are what is in lsusb -v. Using those you can craft a udev rule to create a symlink to a unique device name. I do that with all my boards so that they all get a unique name.
Here is one of my rules:
ATTRS{idVendor}=="2341", ATTRS{idProduct}=="0042",
ATTRS{serial}=="95336333635351F091B1", KERNEL=="ttyACM*",
MODE="0660", GROUP="plugdev", SYMLINK+="board/arduino/mega2560"
That links /dev/board/arduino/mega2560 to whatever /dev/ttyACM* node got created when it was plugged in. That is in /etc/udev/rules.d/50-boards.rules
More on udev here: http://playground.arduino.cc/Linux/Udev
A useful command is udevadm info -a -n /dev/ttyACM0 which lists all the attributes for that device which you can then use in the udev rule.
ls -l /dev/serial/by-id? On my Ubuntu, it shows aliases with rather indicative names (ProductID in particular) and the alias points to the right ttyACM#.