Would using the DMX protocol be of any use here? Relatively easy to 
bit bang, and with some judicious coding, the different channels could  
be made to 'self address'  a new node.

By that I mean, the chips at the node could be programmed to accept 
channel 1 (a sort of broadcast channel), the node chip would read it 
itself discover it has a non assigned node number, accepts the address 
information contained in the broadcast, updates itself, so that a 
channel 1 address won't activate it again, but the new real node 
channel now will.  Some fancy mechanism could be thunked up, to 
persuade a node to respond to channel 1 again if re-addressing became 
necessary. The drawback here would be that nodes could only be brought 
online one at a time. Other than that there are 511 channels worth of 
slaves to be had.

Colin
--
cdb, colin@btech-online.co.uk on 22/08/2008
 
Web presence: www.btech-online.co.uk  
 
Hosted by:  www.1and1.co.uk/?k_id=7988359
 

 
 
 
 

-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist