Hi Jim,
if you are using RS485 as the physical bus structure
you will be restricted to 32 units on the same bus.
You can use the description of multimaster protocols
like PROFIBUS (token passing) or CAN (priorities)
as a starting point, but you have to implement
your own peer to peer protocol on top of that.
Gerold
Am Di, den 29.01.2008 schrieb Jim Brain um 04:30:
Sellam wants to finish the 64 c64 cluster for the next
VCF. I've been
researching ideas for communicating among the machines, and the best
ideas point to using the two synchronous serial ports on the user port
(low wire count, transfers at 250kbps).
But, I have grawn a complete blank on plans for a true peer to peer
(token based or otherwise) networking protocol. Everything I see is
master/slave. RS485 material talks about the hardware layer, but there
is no detail on the protocol layer.
I would think this would be a well researched and innovated area, low
speed communication without a master node. Anyone have any pointers for
things to look into?
Jim