Low Power on nRF5340 SoC with Zephyr & RTC Support

RE: Low Power on nRF5340 SoC with Zephyr & RTC Support

Simonr — Fri, 15 Sep 2023 14:30:34 GMT

System ON IDLE mode is the default sleep mode that the nRF5340 will be set to when no other threads in the RTOS is running. The current consumption of this mode is specified in the nRF5340 product specification.

You can also let only the RTC peripheral run from the external LF crystal to stay in an almost as low sleep mode. When the RTC is the only thread running, it should be almost as low of a current consumption as the system ON IDLE mode.

We don't have a specific sample for going into sleep with the RTC, but we do have this System OFF sample that disables threads and puts the device into a system OFF mode where it will need to be restarted with a button press.

Best regards,

Simon

RE: Low Power on nRF5340 SoC with Zephyr & RTC Support

0x00 — Wed, 13 Sep 2023 12:25:05 GMT

Hi Simon.,

when you talk about IDLE ON what do you refear to?

devzone.nordicsemi.com/.../616856.main.c

Attached my main.c file in which should be clear the logic.

To be more precise, I have a 32kHz XTAL on the circuit connected to P0.00/XL1 and P0.01/XL2. and I would to set an alarm (its internal RTC would be the best choice) every hour to wake the board to sample the analog entities, send the datas by BT and come back to sleep (no retention is needed actually).

It's not clear to me the way to enter and exit from the IDLE (or Sleep) mode.

We have some example for the evaluation?

Many Thanks

RE: Low Power on nRF5340 SoC with Zephyr & RTC Support

Simonr — Wed, 13 Sep 2023 09:20:47 GMT

In the Zephyr RTOS, the device will by default go into a system ON IDLE mode when no threads are running, so this should not be an issue. If the only thing running in your project is the RTC, that should the nRF5340 should be in low power (system ON) mode by default and just wake up when the RTC is triggered. The PM library should not be required unless you want to go into other power modes than the "default" system ON IDLE mode, so that won't be necessary in your use case I believe.

Best regards,

Simon