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Re: Identification of modules

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On 3/31/2017 5:53 AM, Piotr Wyderski wrote:
> 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:

Is that five bits each or five bits total?  Why do I need to know how 
many bits this uses?  I need to know how you plan to distinguish the 
board slots.


> 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.

You didn't answer my question.


>> 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.

"Complex"?  How do you define "complex"?


>> 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.

I guess I still don't understand your system.  I don't see why any parts 
would need to be on the backplane.

Where are all the pieces?  Where is the CPU?  You still have not 
explained the limitations of your slot identification.  How will the 
board know which slot it is in?  Are you trying to identify the boards 
and positions to a central CPU or to the MCUs on each board?

-- 

Rick C

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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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