RE: Disabling APPROTECT on nRF52833 Development Boards

Manan Singhal — Sat, 23 Aug 2025 05:08:50 GMT

Thank you, it worker.

RE: Disabling APPROTECT on nRF52833 Development Boards

tesc — Tue, 19 Aug 2025 11:32:40 GMT

Hi,

On the latest SoC revisions, access port protection gets enabled by default on various resets or wake-up from system off, unless either:

UICR.APPROTECT is programmed to the HwDisabled value of 0x5A, or

the firmware (i.e. the application) writes to the APPROTECT.DISABLE register the SwDisable value of 0x5A.

Either of these will disable approtect. Please note that in nRF Connect SDK there are various APPROTECT related kconfigs which control the behavior of the application firmware in regards to disabling or enabling approtect.

If you erase the device, then UICR.APPROTECT is set to 0xFF and there is no software to write to APPROTECT.DISABLE, so the access port of the device will get automatically protected on the various resets or on wake-up.

For details on the approtect mechanism, please see Access port protection controlled by hardware and software.

Regards,
Terje