System_off example has increased power consumption when using k_sleep iso system_off

[Ypenburg]

I run the system_off example without the system actually going off, by removing all the calls to start the system_off worker. Instead of going to off, I let the system enter sleep mode (k_sleep()).

I enabled wake up on nfc.

After a reset, the system enters sleep (4-5uA sleep current). After waking the system by nfc, the sleep current sometimes becomes 200uA, sometimes stays at 4uA. See picture below.

It seems to be related to the state of the nfc peripheral as this is the only peripheral used.

Any idea how to prevent the system going to sleep with a 200uA sleep current?

[Simonr]

Hi

What SDK version are you using for this? If you haven't already, please move to NCS v3.0.0 as there were fixes for the nRF54L15 made there.

Have you tried enabled logging to see if there's any difference of what happens in the app when you see the difference between when the 200µA and 4-5µA. 

Best regards,

Simon

[Ypenburg]

Hi Simon,

I already switched to v3.0.1 to check if that makes a difference. But the issue remains.

What can I log to see the difference?

I did debug the app and checked if there was a difference in NFC registers values, and there was. So it might be that the NFC peripheral is in a state that draws more power. But the NFC library should take care of this. I tried to re-start the NFC by calling nfc_t4t_done() and nfc_t4t_setup() before k_sleep(). Didn't help.

Thanks,

Renger