I can't beleive this works! :D


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  1. #1
    Join Date
    Aug 2003
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    985

    Default I can't beleive this works! :D

    Hi Guys,
    If you connect an LCD as described in the manual, there are exactly seven port pins left on a 16F84/628. A 3x4 matrix
    keypad generaly requires seven pins, but I was able to flog the
    LCD data port for the keypad scan outputs since no program
    will ever scan the keypad and write to the LCD at exactly the same time.. and now there's four spare pins for speakers, switches, etc.

    At the moment, the only hardware bug is holding down three or
    more keys will cause jargon on the display, so I will stay away from keypad combinations for activating menu functions.

    Now I'm thinking it would be better to use the 4 bit LCD data port
    as inputs for the keypad scan routine, and switch back to output
    for the PBP LCD libraries.
    Cheers, Art.
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