On 6/10/2013 4:58 PM, Barry Gershenfeld wrote:
> I see that Mark already suggested a one-wire system to do this. I'm aware
> of one-wire systems like the one Dallas Semi used,  but I might not want =
to
> piggyback another project onto a current one.  The old serial mice actual=
ly
> were a single-wire (RS-232) setup as well, so there's a proven way.  Now
> you'd have a UART to deal with.   I also sense that as you add wires to t=
he
> interface, the time required to get the information goes down.
>

It doesn't need a UART or a complicated protocol.   Bit banging can=20
easily be used to send the info to any device that has at least 1 pin=20
without using a UART. Stream the same information from the encoder chip=20
over and over using a long pulse for the start of where your main chip=20
would start processing the message.
Advantage of this is you can use multiple rotary encoders and only use 1=20
pin on the main chip for all the encoders  and the main chip doesn't=20
have to use an interrupt , it can read it whenever it has free cycles.

Mark

--=20
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