Unique Device ID

[Dave]

I have a radio board using a NRF51822 with a custom radio protocol. I need a unique identifier, ideally 24bit, 32bit but be acceptable.

I notice in the parameters there is:

Device ID 64bit unique ID for each unit. DEVICEID[0] DEVICEID[1]

Device address bit 64bit. DEVICEADDR[0] DEVICEADDR[1]

I cant think of a mathematical method of reducing the number of bits and presume there isnt a way (64bit to 24bit or 32bit)?

I presume the DEVICEID is unique for every chip? Unless the device ID is made of different fields that can be split?

[Dave]

Yeah. So, I looked at the MAC address ICs which have a EUI-48 id whereby 24bit is said to be a unique id (the other 24bit is manufactures code). That said, if you buy in batches over years, and they are assigned contiguously by ATMEL, common IDs will be encountered. Unless they do it by account, which I doubt.

URL: www.atmel.com/.../atmel-8807-seeprom-at24mac402-602-datasheet.pdf

The obvious solution is post production programming of a contiguous ID, but is an timely step for manufacturing when production numbers are high.

[Paul]

You need to look at your application for the "Unique ID". If all the ID's got uploaded to a database and linked to a server, You can always put a extra column to fix it, or even download it back to fix permanently. I still think the hash idea would work. If it is online, then server can assign an ID back. If it is offline application, I don't see too many reasons to really really have a "Unique" ID.