Joan Ilari had a web page with a design for an integrated keypad and LCD
module, but I can't find it.

The keypad had 12 individual buttons that went into two parallel to serial
shift register chips - it only took two or three pins on the PIC.  It's
trivial to adapt that circuit to 16 buttons with just adding buttons, more
with adding more buttons, another chip and a moderate code tweak.

The keypad and LCD code are separate and the circuit designs aren't
intertwined either, I've used one, the other or both on my breadboard.

http://www.terra.es/personal4/joan.ilari/lcd/lcd.htm

That module likely won't work on matrix pads - each button needs its own line.

Jeff

At 08:04 AM 2/8/02 +0000, you wrote:
>Hello,
>I expect this has probably been discused before.
>I am after ideas/code snippet really, my requirement is a fairly efficient
>keypad routine (I have seen a few very long ones), which is NOT interrupt
>driven.  My own bit of software will decide at what times it is
>appropriate to scan the keypad.  My own software will have multiplexed
>display the time period between outputting new display data may be used
>for keypad debounced, so not worried about debounce, my bit of software
>will sort that aspect out.
>
>Really after ideas for subroutine that gets key value from a 4*4 keypad.
>(I will sort debounce and when to scan).
>Many thanks for any help that you give.

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