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Re: Serial protocol with physical decoding

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On 5/4/2017 1:26 PM, Mark Storkamp wrote:
> In article <590acce3$0$58351$b1db1813$19ace300@news.astraweb.com>,
>  Clifford Heath <no.spam@please.net> wrote:
>
>> On 04/05/17 16:14, Don Y wrote:
>>> I want to push a bit stream through a series of *identical* devices
>>> and have (identical) software running on each determine if that
>>> particular device is being addressed, or not.
>>>
>>
>> Why daisy-chain? If all devices have to be listening anyhow,
>> why not send the same data to all in parallel, and get each
>> one to validate the checksum and determine if the message
>> is intended for them. That way you can use broadcast (groups),
>> and one software failure doesn't take down the chain.
>>
>> Otherwise you start getting into USB-style distribution trees
>> with all the complexity of enumeration, routing, etc. Avoid
>> that if you can, would be my advice.
>>
>
> If each device is identical, and running identical software, how do you
> get the devices to not all think the message is for them?

The message is received by a node and the address is decremented before 
being passed on to the next.  Only when the message address reaches zero 
does the node accept it as being for it.


> How about a hybrid approach where the data stream is connected in
> parallel, but the enable is daisy chained. On initialization, only the
> first device would see the enable, and it would receive and acknowledge
> a message setting its address, then it would set the enable for the next
> device in the chain, and the initialization continues until each has
> received a unique address. This would also solve the synchronization
> issue since one address could be reserved as an 'all listen' address
> that could be used to initiate an action.

Sounds good to me, but I bet there is an issue that hasn't been 
described yet.  When a new node is added to the system the nodes would 
need to be re-synchronized.

This makes me wonder what the purpose of such a network would be.  It 
would be very hard to manage a chain of any length and distance so that 
you knew which node was which.

-- 

Rick C

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Thread

Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-03 23:14 -0700
  Re: Serial protocol with physical decoding Clifford Heath <no.spam@please.net> - 2017-05-04 16:40 +1000
    Re: Serial protocol with physical decoding Mark Storkamp <mstorkamp@yahoo.com> - 2017-05-04 12:26 -0500
      Re: Serial protocol with physical decoding rickman <gnuarm@gmail.com> - 2017-05-04 15:46 -0400
  Re: Serial protocol with physical decoding Jack <jack4747@gmail.com> - 2017-05-04 00:28 -0700
    Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-04 00:48 -0700
      Re: Serial protocol with physical decoding rickman <gnuarm@gmail.com> - 2017-05-04 10:29 -0400
  Re: Serial protocol with physical decoding Reinhardt Behm <rbehm@hushmail.com> - 2017-05-04 16:44 +0800
    Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-04 07:09 -0700
  Re: Serial protocol with physical decoding Tim Wescott <tim@seemywebsite.really> - 2017-05-04 09:54 -0500
    Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-04 10:52 -0700
      Re: Serial protocol with physical decoding Robert Wessel <robertwessel2@yahoo.com> - 2017-05-04 14:53 -0500
        Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-04 13:17 -0700
          Re: Serial protocol with physical decoding Robert Wessel <robertwessel2@yahoo.com> - 2017-05-05 00:30 -0500
            Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-04 23:57 -0700
    Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-13 21:58 -0700
  Re: Serial protocol with physical decoding Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2017-05-05 00:50 +0200
  Re: Serial protocol with physical decoding Les Cargill <lcargill99@comcast.com> - 2017-05-04 18:47 -0500
    Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-04 20:07 -0700
      Re: Serial protocol with physical decoding Les Cargill <lcargill99@comcast.com> - 2017-05-07 09:21 -0500
        Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-07 10:22 -0700
        Re: Serial protocol with physical decoding Jack <jack4747@gmail.com> - 2017-05-08 00:04 -0700
  Re: Serial protocol with physical decoding Martin Riddle <martin_ridd@verizon.net> - 2017-05-06 12:14 -0400
    Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-06 12:29 -0700
      Re: Serial protocol with physical decoding Martin Riddle <martin_ridd@verizon.net> - 2017-05-08 18:53 -0400
        Re: Serial protocol with physical decoding Don Y <blockedofcourse@foo.invalid> - 2017-05-08 18:50 -0700

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