This a very simple PS/2 interface that I made just because I can. Currently, it handles receiving bytes from the keyboard, though it doesn't actually verify start/end bits properly since my keyboard ...

My version of remaking Rob Cai's Arduino Basic PC With VGA Output, which is to use two Arduino AVR boards to create a 8-bit home computer running the TinyBasic runtime with VGA video output and PS/2 ...

Plus, of course, a PS/2 jack to plug in a keyboard and power it up. Interestingly, the 16×2 display is an old Parallax unit, from the days when RadioShack still existed and sold their stuff.

PS/2 sends make-break codes, while USB sends a fixed length data packet which holds the status of six arbitrary codes. The keyboard cannot send more/longer codes, so additional keys are ignored ...