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Jim Granville
02/13/13 14:12
Read: 916 times

#189360 - and also a twisted ring network
Responding to: Oliver Sedlacek's previous message
Oliver Sedlacek said:

An alternative to a shared high speed bus is to use point-to-point links (as promoted by the old Transputer). You would arrange your processors in a grid and each processor would have a link to its nearest neighbour, often thought of in terms of North, East, South and West. Not many processors have four UARTs, so this can be a deal breaker.

Perhaps better suited to 8051 / Small uC is what I've called a twisted ring.

All uC are connected in a ring, using 9 bit UARTS, and all controllers look for an EDGE on the 9th bit. They then extract an agreed count, and replace with replies, and move the signal edge as they do so.
So the 9th bit looks just like a twisted ring counter, as it moves along the loop. This is well suited to similar-slaves, and modern 8051 can do this to > 1MBd

Address is automatic, by location in the loop, and even the total count present can be found by checking how far the 9th bit moved. You also know the slaves are awake, and not crashed, every transaction.

List of 7 messages in thread
Multi-CPU designs      Josť A. Ruiz      02/13/13 02:55      
   Commonly Done       Jim Granville      02/13/13 03:41      
   Fun with network protocols      Oliver Sedlacek      02/13/13 08:55      
      and also a twisted ring network      Jim Granville      02/13/13 14:12      
         Please explain a bit more      Oliver Sedlacek      02/14/13 02:11      
            more details       Jim Granville      02/14/13 04:15      
   I'd use I¬≤C      Erik Malund      02/14/13 10:33      

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