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

[SOK_LiWang]

Hello, I would like to ask about the problem of how to implement SOC shutdown in NCS.
1. In V2.6.0, CONFIG_PM cannot be enabled, it will prompt that there are dependencies that are not defined in advance, only CONFIG_DEVICE_PM and CONFIG_SYSTEM_OFF can be enabled, but I used these two macros to define the function system_off() in the header file. Does not reduce shutdown power consumption
2. Whether system_off () is used, and peripherals need to be closed before I use IIC and SPI in my program
3. I really do not find the corresponding function that can enable the function of reset key. Can you use nrf_gpio_cfg_sense_set to set the wake key? Are there any nrf routines you can refer to?
We also ask the engineers to help us carefully. Thank you very much

[Jan Kowalewski]

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.

[SOK_LiWang]

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?

[Einar Thorsrud]

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.