Originally posted on MAKE:
This week’s Soapbox is a little different. At Maker Faire I got a chance to meet a lot of people that I’ve only known via mailing lists or their work; one of them was Paul Stoffregen from PJRC. He’s the designer and developer behind the Teensy, one of my favorite USB-based microcontroller development systems. While chatting with Paul he mentioned there’s something pretty big Microsoft could do for the maker community, especially now, as Microsoft is working on Windows 8. It’s a little insider-baseball, but anyone who has tried to install drivers on Windows 7 will know it’s not easy, more so if you’re doing something with USB or microcontrollers. It involves CDC. What’s CDC? CDC stands for “Communication Device Class” — it’s one of the default built-in USB interfaces provided by USB host drivers sitting on a computer. The fact that CDC is standardized means that you can plug any CDC devices into your Mac/Windows/Linux computer and they’ll know what to do. With Mac/Linux, they don’t even need a driver at all. For Windows, you don’t need a formal driver program but you do need an “INF” file — this is a little text description giving Windows a hint about the name and ID# of the CDC device you want to plug in. The CDC spec actually defines many types of communication devices. This conversation is specific to CDC’s “Abstract Control Model.”
The reason this is so important is that nearly all hobby microcontrollers with USB use the CDC standard to send serial data back and forth, and it allows microcontrollers to be backwards compatible — just like the Arduino Uno looks pretty much the same to a computer as the Duemilanove. Same with the new Leonardo.