Can application safely erase nRF52832 UICR memory?

[jwsawyer]

Using the nRF52832 and SoftDevice s132.

If the application code disables the SoftDevice, then the application CAN erase UICR memory in the nRF52832 device. The question is SHOULD the application erase UICR memory?

There are regions in the UICR memory that the nRF52832 Product Specification identifies as "Reserved" and "Reserved for Nordic firmware design" and other uses, alongside the "Reserved for customer" fields. But looking at UICR memory as the code is running, there are very few non-0xFF values in the UICR memory range.

So, does it hurt any SoftDevice (or other Nordic library) operations if the UICR memory is erased?

Thanks!

[Susheel Nuguru]

Softdevice uses NRF_UICR->BOOTLOADERADDR in nRF51 (in nRF52 it is called NRF_UICR->NRFFW[0]) to determine if there is a bootloader in your system of not. If you have bootloader and if you erase UICR then, softdevice will think there is no bootloader even though it is physically present in FLASH.

on nRF51 it also uses NRF_UICR->CLENR0 to determine the type of memory protection your device has, but on nRF52 this is not used.

Since your device is nRF52, and IF you do not have bootloader then you can erase UICR without affecting the functionality of softdevice.