AdB to USB with ATmega328P

[nox91]

Hi to all guys, I'm interested in build my own ADB to USB converter but i only have a arduino clone with ATmega328P. I'm not an expert in arduino and co but I noticed that my processor has not a usb interface and i'm thinkig that this is a problem. It's right?
And if it's still possible to buind the converter I have to follow some forethought?
Thanks to all

[AKmalamute]

 I haven't done this myself, but the usual answer is: the 328P doesn't have USB awareness, so you have to create your own.

 There's a 'virtual USB' library that can be used, and I believe TMK has some routines built-in if you want/need to build using that instead of native USB function calls, but it will be more work to make a USB converter when the brains of the device doesn't know what USB or ADB is.