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STM32G071/G081 stucked bit into unique ID?

THAUS.1
Associate

I need to have a unique ID on 32bits. Unique ID of STM32G0x is on 96bits.

It may have some stucked bit for '0', for example for XY wafer position, maybe others (lot #)?

I've seen that " exact information about valid bits not fixed to 0 for given decives are available up on the request":

https://www.st.com/content/ccc/resource/training/technical/product_training/b7/03/bd/99/54/55/4d/47/STM32L4_System_eSign.pdf/files/STM32L4_System_eSign.pdf/jcr:content/translations/en.STM32L4_System_eSign.pdf

It is possible to know which bits will be stucked to '0'?

Thanks a lot!

5 REPLIES 5
TDK
Guru

You could take the 96 bits, feed them into a CRC32 and use the result. Fairly high probability the result will be unique enough.

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THAUS.1
Associate

Thanks TDK for your asnwer, but "fairly high probability" is not safe enough for me :hushed_face: . I really need to know which bits are stucked.

TDK
Guru

It's unlikely that 64 of the 96 bits are unused in order to guarantee a unique 32-bit ID.

If 1:4294967296 is too high a probability for your project, burn your own unique ID into the OTP bits.

If you feel a post has answered your question, please click "Accept as Solution".

I know you won't like this answer, but the best you can do is simply generate your own unique ID when programming the device, as TDK said above.

JW

Hashing will get more "randomness" in the bit patterns, but won't be unique, ie can't really cram down a 96-bit unique into a 32 or 64-bit value and expect it to be "unique" too

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