How to enter system-off mode in NCS V2.6.0?

RE: How to enter system-off mode in NCS V2.6.0?

Einar Thorsrud — Wed, 26 Jun 2024 13:42:36 GMT

Hi,

There are only a few possibel wakeup sources from System off on the nRF52840:

GPIO
NFC (this is demonstrated by the sample in nrf/samples/nfc/system_off)
Pin reset
LPCOMP

Except for pin reset (as long as it is enabled in the UICR), you need to configure the wakeup-source you want before entering system off. The sample you have seen shows how to configure a GPIO as wakeup source.

RE: How to enter system-off mode in NCS V2.6.0?

SOK_LiWang — Wed, 26 Jun 2024 08:35:26 GMT

Hi，lan Kowolewski
I have achieved system sleep through the reference routine, plus my sensor shutdown power consumption is only 7.5uA. Fully in accordance with the calculation expectations of the manual. But I can't turn it on. Only the GPIOTE interrupt of sw0 is set in the system_off routine. I wonder if any interruption of the hardware will wake up the device? Or is there any special config configuration?

RE: How to enter system-off mode in NCS V2.6.0?

Jan Kowalewski — Thu, 20 Jun 2024 18:32:50 GMT

Hello SOK_LiWang ,

did you try to use system off example? (https://github.com/nrfconnect/sdk-zephyr/tree/v2.6.0-rc1-ncs-branch/samples/boards/nrf/system_off). It has wake up on button.

From docs: "Before entering the System OFF mode, the user must make sure that all on-going EasyDMA transactions
have been completed. See peripheral specific chapters for more information about how to acquire the
status of EasyDMA transactions."

So yes, you have to close pending transactions, however if you use CONFIG_DEVICE_PM, IIC and SPI drivers should execute shutdown automatically.