Disabling APPROTECT on nRF52833 Development Boards

[Manan Singhal]

Hi Nordic,

I am currently working with the nRF52833 development board and facing an issue related to the APPROTECT feature. Each time I connect the board, the access protection is re-enabled, which forces us to perform a full erase before every debugging session. This significantly affects the development workflow.

Could you kindly guide me on how to properly disable APPROTECT for development purposes? Specifically, I would like to know the recommended way to ensure that it stays disabled across reboots and reconnections on new development boards.

Looking forward to your guidance.

Best regards,
Manan Singhal

[tesc]

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

[Manan Singhal]

Thank you, it worker.