>=20
> How about a port expander? I've played with the 16 port
> MCP23017 and the 8 port PCF8574. They work quite well and are easy to use=
..

Nah, if you are going to do that, then look at how the MC14025/6/7 remote c=
ontrol ICs implement trinary encoding. No resistors needed. If done on a po=
rt with Interrupt on Change then if a switch is changed so that it causes a=
 port to draw high current then re-read the switches and set the bits back =
to outputs that match the switch states.



--=20
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