[RASP] VirtualBox Raspberry Pi debuging

This article is for the perspective that planning to debug Raspberry Pi connected to (Guest) Ubuntu Virtualbox with USBtoUART and Screen/terminal.

There are two important issues that you may face:

1. You cannot detect USB devices: You probably have a permission issue on your Virtual box. Add your user ID to group vboxusers with this command: sudo usermod -a -G vboxusers $USER, log off, log on and try again. http://askubuntu.com/questions/481693/virtualbox-usb-add-device-filter-does-not-work-under-14-04
2. You cannot listen the ttyUSB0: Your permission of (guest) account should be feasible to the ttyUSB0:
   

   sudo gedit /etc/group
   

   goto line...
   

   dialout:x:20:     
   

   add your "username"
   

   dialout:x:20:username
   

   http://askubuntu.com/questions/40959/how-do-i-connect-to-tty-com-dev-ttyusb0

After that, then you can detect the plug-in usb on-the-fly or before open the virtual machine.
Then, screen /dev/ttyUSB0 115200

(DON"T FORGET TO INSTALL VIRTUALBOX GUEST ADDITION PACKAGE http://virtualboxes.org/doc/installing-guest-additions-on-ubuntu/ and http://www.oracle.com/technetwork/server-storage/virtualbox/downloads/index.html)