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I2C devices with unique identifiers.

Discussion in 'Electronic Design' started by Roberto Waltman, Aug 10, 2012.

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  1. For a project I am working on, I would like to give boards fresh from
    manufacturing a distinct "identity", before they are assigned a serial
    number, or have a MAC address or IP address programmed, etc.

    This could be provided by some devices, such as Maxim's DS2411
    "Silicon serial number" ( with a "Unique, Factory-Lasered and Tested
    64-Bit Registration Number" ) or DS18B20 temperature sensor, ( "has a
    Unique 64-Bit Serial Code Stored in an On-Board ROM" )

    Looking for the least expensive chip with such an ID, with an I2C
    (preferred), SPI or 1-wire interface. Don't care what other
    functionality that chip may have, I just want the unique ID.
    A device that report its own serial number would be OK.

    Any recommendations?

  2. Thanks, that's exactly what I need.
  3. rickman

    rickman Guest

    Dallas did a good job with the one wire parts in general and only using
    one wire is a great thing. But they don't seem to be price competitive
    for who knows what reason. I seem to recall the one wire part that is
    the least expensive is one of their eeproms. I'm pretty sure it is lot
    more than a quarter. Heck, sometimes it is cheaper to emulate a one
    wire part with an MCU, but then you have to do your own serial number

  4. Nico Coesel

    Nico Coesel Guest

    Nowadays a lot of MCUs come with a unique serial number.
  5. I know of a few, such as NXP's LPC1311. But the processor in this
    project does not have this feature. (Can not change that)
  6. For a project I am working on, I would like to give boards fresh from
    Does the board have a flash? Then maybe you already have a 64-bit unique ID

    Leo Havmøller.
  7. Thanks, I am aware of those and no, the only flash is the CPU's
    internal memory.
  8. Uwe Bonnes

    Uwe Bonnes Guest

    How about using a uC with built-in unique ID? E.g. STM32F?

  9. Valid for a new design. This is a respin of an existing product, and
    the CPU (untouchable) does not have an ID.
  10. josephkk

    josephkk Guest

    Wait a minute, they are doing a respin and the old uC is untouchable???
    Hand them a flashlight and a crowbar. They are in dire need. Even in
    aerospace and medical any respin is effectively a new design. New pass on
    ALL qualifications.

  11. rickman

    rickman Guest

    I understand that perfectly. I don't know why they are doing a board
    spin, but they don't want to touch any code they don't have to. Using a
    different MCU chip can wreak havoc on code if it turns out to have
    unsuspected hardware dependencies.

    "There's many a slip, twixt cup and lip."

  12. Precisely. The new and old boards share 80% of the peripherals, and
    that means a lot of the code is already written, tested and known to
    be reliable, if we stay with the same CPU.
  13. josephkk

    josephkk Guest

    Well alrighty then. Family compatible could be potentially acceptable
    then. Depends a lot on just which peripherals are onboard the MCU.

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