At 02:59 PM 7/16/2004 -0400, Shawn Yates wrote:

>What would you recommend for protecting a PIC pin used to detect switch
>closure at the end of a long run of wire?  I have had no problems, but
>since I am relaying the board anyhow, I thought I would ask for input.
>The remote switch is always a switch to ground (its either floating or
>grounded).

Me, I would put a series resistor, 1.5k or more, between the pin and the outside world. On the outside of that, a pair of diodes, shunting any excess or <0 voltage to VCC and ground, and outside that, another 1.5k to limit the current that could possibly be dumped into VCC.

If I were really paranoid, at the I/O pin, a neon lamp.

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