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Re: Identification of modules

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rickman wrote:

> I'm not clear on what you are using the resistive divider for.  Is that
> to identify the module type or the slot?

There are two pieces of information the controller needs
to know, both safely in the range of 5 bits:

1. Where the module is (in which slot).

2. What type of module it is, which says what waveforming
is required to drive it. Say, "I am a 230V module stuffed
with TRIACS" or "the switches are MOSFETs, so use reverse
phase control to decrease the level of EMI" or "mechanical
relays, avoid fidgeting", etc.

The more advanced modules, e.g. carrying an MCU, may want
to use the location info to configure their I2C/CAN address etc.

> The lowest priced 1 wire part I found on Mouser is the DS28E05P+T.  It
> combines the unique 64 bit serial number each 1 wire device has with 112
> bytes of user EEPROM for under $0.50 in quantity.  The EEPROM can be
> programmed in manufacturing to provide a module type identification number.

Just 10 years of retention time, far to small.

> I'm not clear on what your limitations are for identifying the slot
> number.  The easy way is to isolate the 1 wire buses to each slot so you
> are only talking to one at a time.

Would require a complex backplane routing.

> If you don't want to use that many
> pins on your MCU, an analog switch multiplexer will allow the MCU to
> talk to one slot at a time and only need log2(N) I/Os.

Would need to be located on the backplane, which is hard to replace.

	Best regards, Piotr

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Thread

Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-03-31 09:21 +0200
  Re: Identification of modules Don Y <blockedofcourse@foo.invalid> - 2017-03-31 01:31 -0700
    Re: Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-03-31 10:36 +0200
      Re: Identification of modules Don Y <blockedofcourse@foo.invalid> - 2017-03-31 02:16 -0700
        Re: Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-03-31 11:39 +0200
          Re: Identification of modules Tom Gardner <spamjunk@blueyonder.co.uk> - 2017-03-31 11:32 +0100
            Re: Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-03-31 12:59 +0200
          Re: Identification of modules Don Y <blockedofcourse@foo.invalid> - 2017-03-31 11:55 -0700
    Re: Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-03-31 11:30 +0200
  Re: Identification of modules rickman <gnuarm@gmail.com> - 2017-03-31 05:20 -0400
    Re: Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-03-31 11:53 +0200
      Re: Identification of modules rickman <gnuarm@gmail.com> - 2017-03-31 06:16 -0400
        Re: Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-03-31 12:39 +0200
          Re: Identification of modules rickman <gnuarm@gmail.com> - 2017-03-31 13:27 -0400
            Re: Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-03-31 22:14 +0200
              Re: Identification of modules rickman <gnuarm@gmail.com> - 2017-03-31 17:48 -0400
                Re: Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-04-03 10:57 +0200
    Re: Identification of modules John Devereux <john@devereux.me.uk> - 2017-03-31 11:39 +0100
      Re: Identification of modules rickman <gnuarm@gmail.com> - 2017-03-31 13:38 -0400
        Re: Identification of modules Piotr Wyderski <peter.pan@neverland.mil> - 2017-03-31 22:21 +0200
  Re: Identification of modules Joe Chisolm <jchisolm6@earthlink.net> - 2017-03-31 13:02 -0500
  Re: Identification of modules Tim Wescott <seemywebsite@myfooter.really> - 2017-03-31 16:18 -0500

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