Retained Memory for nrf5340 cpu app

RE: Retained Memory for nrf5340 cpu app

Przemek Ostrowski — Fri, 09 May 2025 14:02:33 GMT

RAM retention works for me only when I am debugging, but as soon as I run the application without the debugger it stops working.

I added this code before enter the SYSTEM_OFF and now it all works:

NRF_VMC_S->RAM[0].POWER = 0xFFFFFFFF;

NRF_VMC_S->RAM[1].POWER = 0xFFFFFFFF;

NRF_VMC_S->RAM[2].POWER = 0xFFFFFFFF;

NRF_VMC_S->RAM[3].POWER = 0xFFFFFFFF;

NRF_VMC_S->RAM[4].POWER = 0xFFFFFFFF;

NRF_VMC_S->RAM[5].POWER = 0xFFFFFFFF;

NRF_VMC_S->RAM[6].POWER = 0xFFFFFFFF;

NRF_VMC_S->RAM[7].POWER = 0xFFFFFFFF;

RE: Retained Memory for nrf5340 cpu app

Przemek Ostrowski — Fri, 09 May 2025 12:01:27 GMT

Hi leap_lede did you make it work?
There is now overlay file for nrf5340 on the main branch: https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/boards/nordic/system_off/boards

However, I don't think it works correctly. When I run it on my nRF5340DK board the boot count gets lost unless i keep the button pressed.
I think the RAM content is not being correctly configured to refreshed its content in the SYSTEM_OFF - see the log - i pressed the wake up button twice.
Amanda Hsieh how can I configure RAM to be powered in SYSTEM_OFF or how can I verify if it is actually powered?

Kind regards,
Przemek

RE: Retained Memory for nrf5340 cpu app

stepen — Tue, 25 Feb 2025 12:16:09 GMT

Hi Amanda,

I have the exact same question but for a nrf9151dk board. I tried to create a 'nrf9151dk_nrf9151_ns.overlay' file with the followin content

/ {

aliases {
retainedmemdevice = &sram0_ns_app;
};
};

.. but nothing good happened. (retained.c:73: undefined reference to `__device_dts_ord_56'). If I use &sram0 I get more or less the same. Not sure what ro do here ?

RE: Retained Memory for nrf5340 cpu app

Amanda Hsieh — Mon, 09 Dec 2024 19:28:35 GMT

Hi,

You can use the content of this overlay for nRF5340DK.

Regards,
Amanda H.