Weak handler when writing to GPREGRET?

[Javier Cardona]

Hi,

I'm trying to use the GPREGRET register to save some state across resets. It seems to work as documented, but I'm getting the following error after each write operation to the register:

:ERROR:Fatal
:INFO:Hit weak handler

Interestingly, the stored value is preserved. If I comment out this line

NRF_POWER->GPREGRET = r;

the exception goes away (but I lose the value of r, of course).

Any suggestions?

Thanks,

[Daniel Wang]

You need to use the function sd_power_gpregret_set(). When the softdevice is enabled, you have restricted access to the POWER register(see this link), so you need to use the API(sd_power_gpregret_set() in this case).

[Javier Cardona]

Hi Daniel,

Thanks! I'll test tonight and report, but this seems to be right answer.