This video demonstrates HID-class serial communication for AVR microcontrollers using the V-USB library (a software-based USB implementation). The details of the project can be found at http://rayshobby.net/?p=7363. It works for most AVRs that do not have hardware USB support. The code is implemented as an Arduino library, and the host software is written in Processing. It is cross-platform and looks similar to a standard serial monitor.
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