Store a variable state across SYSTEM OFF and Complete Power Off

[german_wings]

Hello,

I am trying to write a application that can store a simple "INTEGER" value , I want to store the Integer value as 0 or 1 , I beleive RAM Retention would only work in scenes where The system is in OFF mode , but if the chip has run out of power completely I dont think RAM data would be present ? Or RAM Retention does not work the way I am thinking.

I am finding the SDK documentation very confusing "pstorage" ,

I am using NRF 52 DK , SDK 15.0 and BLE Functions

Thank You,

[Kenneth]

RAM cannot retain any data when the chip is powered off, in such case the data must be stored in flash. Check out:

https://devzone.nordicsemi.com/f/nordic-q-a/51002/pstorage-invalid_addres-store-and-load/204288#204288 

In system OFF you can store data in NRF_POWER->GPREGRET register for instance.

[german_wings]

Hey Kenneth , Thanks for your response , Can you share a example ? on this

Kenneth said:

In system OFF you can store data in NRF_POWER->GPREGRET register for instance.

[Kenneth]

main()
{
if(NRF_POWER->RESETREAS == wakeup from system OFF)
{
read NRF_POWER->GPREGRET;
}

your code;

if(go to system OFF)
{
write to NRF_POWER->GPREGRET;
NRF_POWER->SYSTEMOFF = 1;
while(1);
}
}

[S98VN]

Hi Kenneth, 
How can i "read NRF_POWER->GPREGRET;" and "write to NRF_POWER->GPREGRET;"
Thanks your help.