I have not used switches directly on a chip or PIC in years.

Using a few penny resistors, I create a switch array so that when a switch is
pressed, a particular voltage is created, say 4.5v, 4v, 3.5v, etc. I then attach
the end to an A/D pin and read that pin every 10mS or so. I can usually get
8-10 switches on a 5v PIC.

Another advantage not obvious is that you only need to protect ONE PIN
from ESD instead of protecting 10. Cheaper, easier layout.

My schematic is somewhere in the PICLIST... I think the banner is "7
switches on one PIC pin" or something.

--Bob A

On 7/14/09, Jinx <joecolquitt@clear.net.nz> wrote:
> Added this page
>
> http://home.clear.net.nz/pages/joecolquitt/input_select.html
>
> Part of an ongoing project, hopefully will post the whole thing shortly
>
> wbr
>
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