This is the keypad (kp.) object, it allows you to work with:
A "matrix" keypad with up to 64 keys (8 scan lines by 8 return lines); or
A "binary" keypad with up to 254 keys (where 8 return lines supply the binary code of the key pressed).
Flexible mapping for scan and return lines — use any I/O lines, in any order. Scan lines can double as LED control lines.
Ability to auto-disable the keypad when a certain key event/code combination is encountered.
Ability to detect keypad lockup (useful for capacitive touch and other types of sensor keypads).