This is a very wide topic, depending on what type of input device you have. It could be
a MP3 player with just 4 buttons
a central heating system with 8 buttons
an ATM with 8 buttons and a numeric keypad
a reconfigurable touch screen
keyboard, video, mouse system
The display could be anything from a line of LEDs to miniscule phone displays to multiple widescreen displays. UI design for phones is completely different from UI design for websites.
If you could narrow you requirements, someone might be able to give you a reference.
