nrf52 RAM Retention issue

[vishal]

Hi, In my project i would like to save 100 bytes of information in RAM before going to System-off sleep mode.I have tested the example project given in sdk11 works okay.Have used the same in my application as well.I am using softdevice S132 .Configured a button to wake up. My issue begins here :-( -After programming my board I used the push button to wake my device,the RAM data was available and works perfectly.But if I power cycle the board once,and after my device sleeps if I wake my device by pressing the push button the RAM details are not read.But what I noticed is the register GPREGRET was written to and read as expected.

-Should i take any special care while saving data to RAM?

[Hung Bui]

Which part of the memory do you plan to retain ? Could you post your code you use for memory retention ? I'm thinking maybe the start up code may clean up the memory part you used. You may want to create a RAM section with NoInit check box checked in Project Option -> Target -> IRAM2

It's a note at section 18.2 i the nRF52 Spec v1.1 saying: Note that these registers are usually overwritten by the startup code provided with the nRF application examples.