I2C devices with unique identifiers.

[Roberto Waltman]

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]

I use the Microchip 25AA02E48 in several products.

Thanks, that's exactly what I need.

 

[rickman]

Thanks, that's exactly what I need.

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

 

[Nico Coesel]

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.

 

[Roberto Waltman]

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)

 

[Leo Havmøller]

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.

 

[Roberto Waltman]

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.

 

[Uwe Bonnes]

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

 

[Roberto Waltman]

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.

 

[josephkk]

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.

?-)

 

[rickman]

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

 

[Roberto Waltman]

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.

 

[josephkk]

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.

?-)