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I2C devices with unique identifiers.

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

  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?

    Thanks,
    --
    Roberto Waltman

    [ Please reply to the group,
    return address is invalid ]
    Roberto Waltman, Aug 10, 2012
    #1
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  2. Roberto Waltman

    Joe Chisolm Guest

    On Fri, 10 Aug 2012 13:47:30 -0400, Roberto Waltman wrote:

    > 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?
    >
    > Thanks,


    I use the Microchip 25AA02E48 in several products. It's SPI but the
    24AA025E48 is I2C. They will run you about $0.23 in a SOT-23
    package. Get them from Mouser,Digikey,Avnet or direct from Microchip.
    Good news is you also get some EEPROM along with the MAC address.

    --
    Chisolm
    Republic of Texas
    Joe Chisolm, Aug 10, 2012
    #2
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  3. Joe Chisolm wrote:
    >> Looking for the least expensive chip with such an ID,


    >I use the Microchip 25AA02E48 in several products.


    Thanks, that's exactly what I need.
    --
    Roberto Waltman

    [ Please reply to the group,
    return address is invalid ]
    Roberto Waltman, Aug 10, 2012
    #3
  4. Roberto Waltman

    rickman Guest

    On 8/10/2012 5:36 PM, Roberto Waltman wrote:
    > Joe Chisolm wrote:
    >>> Looking for the least expensive chip with such an ID,

    >
    >> I use the Microchip 25AA02E48 in several products.

    >
    > Thanks, that's exactly what I need.
    > --
    > Roberto Waltman


    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
    programming!

    Rick
    rickman, Aug 11, 2012
    #4
  5. Roberto Waltman

    Nico Coesel Guest

    rickman <> wrote:

    >On 8/10/2012 5:36 PM, Roberto Waltman wrote:
    >> Joe Chisolm wrote:
    >>>> Looking for the least expensive chip with such an ID,

    >>
    >>> I use the Microchip 25AA02E48 in several products.

    >>
    >> Thanks, that's exactly what I need.
    >> --
    >> Roberto Waltman

    >
    >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
    >programming!


    Nowadays a lot of MCUs come with a unique serial number.

    --
    Failure does not prove something is impossible, failure simply
    indicates you are not using the right tools...
    nico@nctdevpuntnl (punt=.)
    --------------------------------------------------------------
    Nico Coesel, Aug 12, 2012
    #5
  6. Nico Coesel wrote:
    >Nowadays a lot of MCUs come with a unique serial number.


    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)
    --
    Roberto Waltman

    [ Please reply to the group,
    return address is invalid ]
    Roberto Waltman, Aug 12, 2012
    #6
  7. > 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.


    Does the board have a flash? Then maybe you already have a 64-bit unique ID
    available.

    Leo Havmøller.
    Leo Havmøller, Aug 12, 2012
    #7
  8. Leo Havmøller wrote:
    >Does the board have a flash? Then maybe you already have a 64-bit unique ID
    >available.


    Thanks, I am aware of those and no, the only flash is the CPU's
    internal memory.
    --
    Roberto Waltman

    [ Please reply to the group,
    return address is invalid ]
    Roberto Waltman, Aug 13, 2012
    #8
  9. Roberto Waltman

    WangoTango Guest

    In article <>, jchisolm6
    @earthlink.net says...
    > On Fri, 10 Aug 2012 13:47:30 -0400, Roberto Waltman wrote:
    >
    > > 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?
    > >
    > > Thanks,

    >
    > I use the Microchip 25AA02E48 in several products. It's SPI but the
    > 24AA025E48 is I2C. They will run you about $0.23 in a SOT-23
    > package. Get them from Mouser,Digikey,Avnet or direct from Microchip.
    > Good news is you also get some EEPROM along with the MAC address.
    >
    >

    I second the recommendation, I use both flavors of these guys a regular
    basis. As easy to use as any serial EEPROM and cheap.
    WangoTango, Aug 13, 2012
    #9
  10. Roberto Waltman

    Uwe Bonnes Guest

    In comp.arch.embedded Roberto Waltman <> wrote:

    > 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?


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

    Bye
    --
    Uwe Bonnes -darmstadt.de

    Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
    --------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
    Uwe Bonnes, Aug 14, 2012
    #10
  11. Roberto Waltman

    Smeghead Guest

    That's very interesting info on the 24AA025E48. We currently use
    STm24cxx256 part on our boards both to store a MAC address (and a bunch o
    other programming information). We bought a block of 4096 addresses fro
    the IEEE, but keeping track of them all and having to program each boardse
    prior to use is something of a pain.

    While we need far more than the 2kbits available on the 24AA025E48, i
    might be very much worthwhile adding one just for the MAC. Reading th
    datasheet, it looks as if this is a valid IEEE MAC address as microchi
    have registered for an OUI. Given that and the low price of the parts,
    might well be pushing for one of these on the next rev of our board as i
    cuts out a programming step.

    Thanks for the info!

    >On Fri, 10 Aug 2012 13:47:30 -0400, Roberto Waltman wrote:
    >
    >> 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?
    >>
    >> Thanks,

    >
    >I use the Microchip 25AA02E48 in several products. It's SPI but the
    >24AA025E48 is I2C. They will run you about $0.23 in a SOT-23
    >package. Get them from Mouser,Digikey,Avnet or direct from Microchip.
    >Good news is you also get some EEPROM along with the MAC address.
    >
    >--
    >Chisolm
    >Republic of Texas
    >


    ---------------------------------------
    Posted through http://www.EmbeddedRelated.com
    Smeghead, Aug 14, 2012
    #11
  12. Uwe Bonnes wrote:
    >How about using a uC with built-in unique ID? E.g. STM32F?


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

    [ Please reply to the group,
    return address is invalid ]
    Roberto Waltman, Aug 14, 2012
    #12
  13. Roberto Waltman

    Joe Chisolm Guest

    On Tue, 14 Aug 2012 15:35:51 -0500, Smeghead wrote:

    > That's very interesting info on the 24AA025E48. We currently use a
    > STm24cxx256 part on our boards both to store a MAC address (and a bunch
    > of other programming information). We bought a block of 4096 addresses
    > from the IEEE, but keeping track of them all and having to program each
    > boardset prior to use is something of a pain.
    >
    > While we need far more than the 2kbits available on the 24AA025E48, it
    > might be very much worthwhile adding one just for the MAC. Reading the
    > datasheet, it looks as if this is a valid IEEE MAC address as microchip
    > have registered for an OUI. Given that and the low price of the parts, I
    > might well be pushing for one of these on the next rev of our board as
    > it cuts out a programming step.
    >
    > Thanks for the info!
    >

    [snip]

    It's trivial to use your own OUI with these parts. Just slam
    yours in the 1st 3 bytes when you program the EMAC block

    --
    Chisolm
    Republic of Texas
    Joe Chisolm, Aug 15, 2012
    #13
  14. Roberto Waltman

    josephkk Guest

    On Tue, 14 Aug 2012 18:38:13 -0400, Roberto Waltman <>
    wrote:

    >Uwe Bonnes wrote:
    >>How about using a uC with built-in unique ID? E.g. STM32F?

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


    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.

    ?-)
    josephkk, Aug 16, 2012
    #14
  15. Roberto Waltman

    rickman Guest

    On 8/16/2012 3:09 AM, josephkk wrote:
    > On Tue, 14 Aug 2012 18:38:13 -0400, Roberto Waltman<>
    > wrote:
    >
    >> Uwe Bonnes wrote:
    >>> How about using a uC with built-in unique ID? E.g. STM32F?

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

    >
    > 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.
    >
    > ?-)


    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."

    Rick
    rickman, Aug 16, 2012
    #15
  16. rickman wrote:
    >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.


    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.
    --
    Roberto Waltman

    [ Please reply to the group,
    return address is invalid ]
    Roberto Waltman, Aug 17, 2012
    #16
  17. Roberto Waltman

    josephkk Guest

    On Thu, 16 Aug 2012 22:19:49 -0400, Roberto Waltman <>
    wrote:

    >rickman wrote:
    >>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.

    >
    >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.


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

    ?-)
    josephkk, Aug 18, 2012
    #17
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