nrf52 enables protection by accident?

[AMarch01]

Somehow a program I have running on a nrf52840-DK board will enable protection. This kind of screws up the small application I am testing because it seems to lock out the UICR registers I am using.

Has this been seen before. Am I somehow crashing and slamming the bits?

A M

[Priyanka]

Hi Anthony,

Yes, this is a known behavior. If your application is somehow writing to UICR->APPROTECT (e.g., setting it to 0x00), or if you have ENABLE_APPROTECT defined in your project, the device will enable protection after a reset. 

Am I somehow crashing and slamming the bits?

This might not be the issue as it's quite a rare situation. I think your code is enabling APPROTECT somehow.

Please check your code to see if something writes to NRF_UICR->APPROTECT or defines ENABLE_APPROTECT.

Regards,

Priyanka