enabling and wake up from sleep mode (systemoff)?

[lalith88]

through RTC i am trying it but it is not happening can  you give any propre example one for the sleep mode enabling and wakening up from the sleep mode.

[Edvin]

Hello,

Unfortunately, it is not possible to wake the nRF5340 from systemoff using the RTC. This is only possible on the nRF54L-series, which has a GRTC. Other nRF devices will not be able to have the RTC running in SystemOff, and hence, it is not possible to wake up from it. If you need to wake on a timer, you need to use systemOn-Idle. 

You can read about systemoff on the nRF5340 here:

https://docs.nordicsemi.com/bundle/ps_nrf5340/page/chapters/reset/doc/reset.html#ariaid-title5

So from systemOff, the only things that can wake up the nRF5340 are GPIO interrupts, reset pin, power on reset or NFC. If you need to wake it up from a timer, you need to have an external timer module that can give a pulse after a given amount of time.

Best regards,

Edvin

[lalith88]

Hello Edvin,

Thank you for clarifying about the limitation with SystemOff and RTC wakeup on the nRF5340.

I would like to understand more about SystemOn-Idle:

1. How exactly does SystemOn-Idle work on the nRF5340? Is it automatically entered when the CPU executes WFI/WFE, or do we need to explicitly configure it through the Zephyr Power Management API?

2. Are there any examples or reference projects showing how to put the device into SystemOn-Idle and then wake up again using the RTC or with out RTC?

3. Could you please share some current consumption numbers for nRF5340:

   • In SystemOn-Idle with RTC running.

   • In SystemOn-Idle without RTC.

   • Compared to SystemOff.

This will help me evaluate whether SystemOn-Idle meets my use case, since I need a periodic wakeup from the RTC while minimizing power consumption.

Best regards,
Lalith