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I2C devices with unique identifiers.

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

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Reply to
Roberto Waltman
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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
Reply to
Joe Chisolm

Thanks, that's exactly what I need.

-- Roberto Waltman

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Reply to
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

Reply to
rickman

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=.)
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Reply to
Nico Coesel

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

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Reply to
Roberto Waltman

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

Leo Havmøller.

Reply to
Leo Havmøller

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

-- Roberto Waltman

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Reply to
Roberto Waltman

I second the recommendation, I use both flavors of these guys a regular basis. As easy to use as any serial EEPROM and cheap.

Reply to
WangoTango

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

Bye

--
Uwe Bonnes                bon@elektron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
Reply to
Uwe Bonnes

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

-- Roberto Waltman

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Reply to
Roberto Waltman

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.

?-)

Reply to
josephkk

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

Reply to
rickman

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

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Reply to
Roberto Waltman

a=20

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

?-)

Reply to
josephkk

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