> Not completely clear to me - what happens if one of the 
> controllers in the middle of the chain dies/hangs/etc? 
> Actually I'm thinking about the same application - greenhouse 
> controller network, just not for commercial application.

The nodes were (probably still are) connected in a chain. Each chain has
a 'head end' controller. This head end controller simply switches the
power off and back on to get all node controllers in their reset state.
We used 16F819's, which were at that time the cheapest PICs with
self-write capability (update firmware) and a protected part in the
flash (for the bootloader). The head-end controllers were also connected
in a chain, this chain was connected to the PC.

Wouter van Ooijen

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Van Ooijen Technische Informatica: www.voti.nl
consultancy, development, PICmicro products
docent Hogeschool van Utrecht: www.voti.nl/hvu
 
 

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