Two keys from one keypad with standard routines can be a bit tricky
but can be done..   If two keys on different rows AND columns are down
you will read all four keys that make a square as down.  If one key goes
down then look, if state doesn't change then 1 key press.  If state
changes within the keypress time then first key down is one corner of
the box, the other key down is the opposite corner of the box.  (will
only read two keys if they are on the same row or same column..)

  IF miracle of miracles (at pic speeds anyway) both keys are pressed at
the same time and they are not on the same row or same column then you
have to ignore the keypress since you don't know which diagonal to use.
Should happen very rarely if you use an interrupt on change for keyboard
scanning or poll it at a reasonably fast rate..


dragon wrote:
>
> been doing basic i/o with 16f84 " if input do output "
> but i now need to be able to scan a 4 x 4 keypad and get
> 1 and 2 key inputs from it. Any suggestions or pointers
> would be greatly appreciated.
>
> Henry dragon@topher.net