which registers cant be erasable in nrf52, which can be possible to Read/Write

[saiteja]

hi, i am using NRF52 custom board. i want to provide serial number to each board, which i want to read or write any time using my firmware. if i erase the bord it should not erase the serial number registers is it possible to make it happen. please give me suggestion. Currently, i am using UICR registers to read and write serial number in it. but if i erase chip. these registers also erasing.

Thankyou.

[Jørgen Holmefjord]

Hi,

I think UICR is the best alternative for storing serial number. You have a couple of options to leave the serial in UICR when flashing your application:

1. Use --sectorerase option in combination with --program when flashing, instead of --eraseall. With this option, only the targeted non-volatile memory pages, excluding UICR will be erased.
2. If you need to erase whole chip, you can read UICR before erasing, and reflash it after application:

nrfjprog --readuicr uicr.hex

nrfjprog --eraseall

nrfjprog --program application.hex

nrfjprog --program uicr.hex

Best regards,

Jørgen

[Roger Clark]

Have you considered using the MAC address as the serial? It comes pre programmed.

But I am not sure if they are absolutely guaranteed to be unique