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PSoC 5, 3 & 1 MCU

New Contributor

Hi everyone,

   

 I am considering implementing Cypress repeater Algorithm for PLC (AN62487). My doubt is if we have 15 slaves and the repeater reaches not just 1 node next to it but 2 or more nodes and if we don't have 100% reach ability node-to-node (less say it could take 1-3 messages before one node reads correctly a message).

   
    According to the explanation of AN62487 document on page 2-3 it seems that if a repeater message reaches 2 nodes ahead of it, the 2 node will stop repeating the message because both receive a confirmation from each other and plus the nodes ahead of these 2 have not received the message yet due to the fact we don't have 100% reach ability.   
   
        
   
    Here I try to explain the scenario trough a scheme:   
   
        
   
    A--B--C--D--E--F--G--H--I--L   
   
        
   
    A wants to communicate with L.   
   
        
   
    A has sent direct message to L, which can't see A, A sends broadcast message.   
   
    B and C receive the broadcasted message from A.   
   
    After direct message to L, both send broadcast message. Both receive a confirmation from each other so they stop repeating the message.   
   
    Now, if none of the further nodes ( D,E, ...) has received the broadcasted message from B and C (bad luck), the message is lost and never reach L.   
   
        
   
    My question is: Does the algorithm works if a node next to another does't received with 100% certainty a message.     
   
    Thank you in advance for the support.    
   
        
   
    - J   
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Esteemed Contributor

Seems to me the algortithim has each node operating as a repeater

   

requiring acknowlegement, and each node repeats to its neighbor until it

   

achieves acknowlegement. So the packet propagates to each nearest

   

neighbor until complete.

   

 

   

    

   

          http://www.cypress.com/?docID=44756

   

 

   

Regards, Dana.

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New Contributor

I think that with the number of hops value in the packet eliminates my doubt about the message reaching more than 1 neighbour node.

   

Now I am concern about the case 2 nodes send at the same time a packet. Will the packets collide and be destroyed?

   

Thank you again, your help is appreciated !!

   

 

   

- J

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Esteemed Contributor

Use CSMA in the protocol, much like Ethernet, to avoid collisions.

   

 

   

    

   

          http://www.cypress.com/?docID=46702

   

 

   

Regards, Dana.

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