Retained Memory for nrf5340 cpu app

[leap_lede]

Hello,

We have an nrf522840 board using retained memory feature following this sample and using the NRF_RETENTION setting: 

https://github.com/zephyrproject-rtos/zephyr/tree/191d38dee89dd1e03e525ec2d24a8a1210751517/samples/boards/nordic/system_off

We are upgrading to use the nrf5340 chip and trying to adapt the code. We are setting to use RETAINED_MEM but are having trouble with retainedmemory device not being  defined. 

This is the line throwing an error: const static struct device *retained_mem_device = DEVICE_DT_GET(DT_ALIAS(retainedmemdevice));

The sample has some definitions of the device for the nrf54 boards, but none for the nrf53. 

Appreciate any pointers. We are building using the nrf5340ns.

[Amanda Hsieh]

Hi, 

You can use the content of this overlay for nRF5340DK.

Regards,
Amanda H.

[stepen]

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 ?

[Przemek Ostrowski]

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

[Przemek Ostrowski]

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;