Power consumption nRF52

[StevenGhe]

Hello there,

Past few days/week I've been looking into how to limit power consumption using my Adafruit Feather Express nRF52840. I've asked in the general Slack but no response.

Currently I have about 1.1 mA current idle, and I'd like to 'sleep' the device as much as possible.
Looking at the Power Management section from Zephyr I understood you can either choose to set a power state to the system or to certain devices from your system.

Using pm_power_state_set() I'm able to set the power state. However after testing and looking into the code, nRF52 only supports SYS_POWER_STATE_DEEP_SLEEP_1 which results in powering the system completely off (relevant power.c file). This is too much, as I'd like to keep the memory/context the same.

Is there another way of putting this device to sleep besides pm_power_state_set? As I'm using the bluetooth stack, as far as I am aware there is no Bluetooth device in my build. There is no way to way to disable bluetooth (related issue on disabling Bluetooth), so I'm kind of stuck, unable to limit power consumption.

Sorry if this 'blank' issue is related to a certain topic, I was not sure which one it belonged to.

Thanks in advance,

Steven

[gmarull]

Have you checked https://github.com/zephyrproject-rtos/zephyr/tree/main/samples/boards/nrf/system_off ?

[ceolin]

Based on first comment in #31162 this seems to be the only runtime state supported by Nordic boards. @gmarull do you know if this target supports other states that are just not implemented ?

[ceolin]

@StevenGhe btw, you are probably using an old Zephyr version. The way pm states are implemented now is very different.

[StevenGhe]

As soon as I looked at the sample gmarull showed, I realized that the newer versions indeed have a lot of changes.

Quite sure I will be able to do some sleep/idle current reduction with the presented sample, if any issues arise I will make another ticket :).

@ceolin, the reason I created this ticked that other power.c files like for example this stm32l4 one had way more features. And given the nRF52 popularity it seemed weird it had next to nothing.

[ceolin]

@StevenGhe the states implemented by each platform may vary, keep this in mind. This depends on watch each hardware supports.

[gmarull]

@StevenGhe would you mind closing the issue if it answers your questions? Feel free to open other issues or post to https://github.com/zephyrproject-rtos/zephyr/discussions