[simpits-tech] What's on the Workbench?

[Ross Hutton]

 --- Stuart Whelan <buffy@paradise.net.nz> wrote: 
> 2) This is my baby. :) I am programming 28 pin PIC
> micro controllers to
> allow devices to be controller from the PC via the
> serial port, and to
> allow hardware to talk back to the PC. I have
> designed a token ring type
> communications protocol and worked it so that new
> PIC modules to be
> bolted into the ring as desired. The PIC's get a
> packet, and if it is
> not for them they pass it on to the next PIC.
> Several times a second a
> empty packet gets transmitted and any PIC's with
> data for the PC can use
> it to send a reply. 

Hey, I'm following a similar route using AVR's (not
token ring at the moment though). What sort of
hardware interface are you using for the network? 

I'm playing about with the hardware SPI interface on
the AVR's but the problem with that is that the small
controllers do not have instructions  to control it
(they can only be slaves). 

I think that I'll end up just using the on-chip
hardware UART's instead. Using a token ring type
system like yours would make for a fairly simple
hardware/software interface that only needs one UART
per chip. 

The Tx of the first AVR would go to the Rx of the next
in the chain until finally the Tx of the last AVR goes
to the Rx on the PC. The Tx of the PC would go to the
Rx of the first AVR. It's a nice way to go for small
systems.



=====
--
Ross

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