Microcontroller enumerates as USB printer — can be programmed by printing
 

This is a fascinating concept. We’re not sure of its usefulness, but it definitely stands on its own just for the concept. [Dean Camera] just added a new HID class to the LUFA project that lets you flash AVR chips by printing to them. This means once you have a file like the one seen open in Notepad above, you can just click on File, then on Print, and the firmware will be uploaded to the chip.

[Dean] is the creator of the LUFA project and still likes to get his hands dirty hacking around with it. This idea came to him while he was exploring the concept of using the MIDI protocol to program a chip. That didn’t pan out because of the way Microsoft has handled MIDI in newer versions of Windows. But he did get the idea of making LUFA identify itself as a simple USB printer. He dug into the specification and figured out how to do that. Once Windows connects to the device it doesn’t really care what data gets sent to it. So [Dean] wrote a parser for the bootloader which could accept the incoming hex code and write it to the chip’s program memory.

http://hackaday.com/2013/05/10/micro...8Hack+a+Day%29