Serial protocol with physical decoding

From	Don Y <blockedofcourse@foo.invalid>
Newsgroups	comp.arch.embedded
Subject	Serial protocol with physical decoding
Date	2017-05-03 23:14 -0700
Organization	A noiseless patient Spider
Message-ID	<oeegko$e86$1@dont-email.me> (permalink)

Show all headers | View raw

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.

It seems like the simplest way to do so is to require each device
to examine an address field in the packet and, if '0', assume the
data that follows is intended for its consumption.  If not,
decrement the address and pass the packet along.

(I.e., the protocol would require a SERIAL_IN and SERIAL_OUT
signals)

Of course, this means a failure of any device renders those that
follow it inaccessible.  That's acceptable.

It also means there is a latency proportional to the device address
inherent in the protocol.  Also acceptable (the data source can
take that into consideration when creating the message stream).
And, the incremental latency can be made pretty small.

Another downside is the cost of updating data on *all* (multiple)
devices as this requires N messages.

An alternate message format (or, a cleverer encoding of the above)
could be used to allow a single COMPOSITE message to be propagated
in which a node encountering a '0' address field strips the data
that is intended for its use and then reconstructs a message
bearing a '0' address field with the BALANCE of the data that it
then passes to the next device, in series.  In effect, letting
each subsequent device strip off "its" data before passing the
remainder along.

[When no data remains, the message dissipates]

As such, you could "address" any set of contiguous addresses
by creating an initial message of the form:
     <first_target_ID> <first_datum> ... <last_datum>
where the number of data present in the message implicitly defines
the *last_target_id* relative to the first_target_id.

Any problems with this sort of kludged encapsulation?

Back to comp.arch.embedded | Previous | Next — Next in thread | Find similar | Unroll thread

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

csiph-web