STM32G071/G081 stucked bit into unique ID?

[THAUS.1]

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!

[TDK]

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

[THAUS.1]

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]

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.

[waclawek.jan]

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

[Tesla DeLorean]

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