Larry McKibben wrote:

>  I'm not sure I want to add the complicity of RS485.
> .
> .
> .
> Reconsidering, I will abandon the USART.

   Hello, Larry.

   Why not to use the idea of Microchip ICSP interface in this context.
Plus for more reliability I'd recommend star topology instead of bus.
Plus for the same reason I'd recommend a sort of MAX232 stuff as
bus drives. (I bought ICL232CPE for less then 1$)
   What do I mean. PIC16F8XX has a lot of I/O pins. Set two lines
(DataIn and DataOut) among central chip and each peripheral chip.
Add two common lines (Reset and Syncro) from central to periferal.
You'll get a fully static system with easy programming and debugging.
   The idea is quite clear. After "Reset" you send commands in, say, 4 bits,
synchronizing each bit by "Syncro" front. Then you send and receive data
simultaneously going on with the synchronization.

   Good luck.
   Mike.

PS: Microchip ICSP has DataIn and DataOut in one line. The above
       idea looks more like an Atmel's SP.

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