Help with sleeping/low power mode on nRF5340

RE: Help with sleeping/low power mode on nRF5340

user75734 — Thu, 21 Apr 2022 10:59:43 GMT

Hi again Glen

You have just downloaded the project from the nRF53 power optimization blog post, right? You will need to edit the pm_power_state_set() function to allow I.E. the SUSPEND_TO_RAM state instead of just the SOFT_OFF state.

In the latest nRFConnect SDK releases (1.9.1) there is a test project doing that \NCS_FOLDER\v1.9.1\zephyr\tests\subsys\pm\device_wakeup_api\src\main.c here. Please give it a look.

Best regards,

Simon

RE: Help with sleeping/low power mode on nRF5340

user73356 — Wed, 20 Apr 2022 16:32:16 GMT

It's not going to sleep at all.

Oh - I found the problem, but I don't know the solution:

pm_power_state_force calls pm_state_set which calls pm_power_state_set, and that function ONLY supports

PM_STATE_SOFT_OFF.

__weak void pm_power_state_set(struct pm_state_info info)

{

switch (info.state) {

case PM_STATE_SOFT_OFF:

nrf_regulators_system_off(NRF_REGULATORS);

break;

default:

LOG_DBG("Unsupported power state %u", info.state);

break;

}

So how are you supposed to go to the various sleep states? I was hoping to use

PM_STATE_SUSPEND_TO_RAM.

What I really need is to go to the lowest power state possible without losing my place in the code while waiting for a GPIO interrupt to wake me up (When you wake up from SOFT_OFF it's like a system reset where you've lost everything - I want to continue from where I went to sleep).

The spm.conf file is the configuration file for the Secure Partition Manager - I was just testing adding the power management configuration options to there in case that was required for going to low power mode when using a project with SPM.... turns out that wasn't the issue. My main prj.conf does have the CONFIG_PM_DEVICE setting and it's fine.

RE: Help with sleeping/low power mode on nRF5340

user75734 — Wed, 20 Apr 2022 10:44:48 GMT

Can you describe how you see the immediate wake up when calling the STANDBY? Does the device go to sleep/idle mode at all? Can you also let me know what build error(s) you're seeing if you set CONFIG_PM_DEVICE=y, because this should be enabled to let you do necessary power management operations like turning off device clocks and peripherals. Please also note that it should be set in the prj.conf file, what's this spm.conf file you are using?

Best regards,

Simon

RE: Help with sleeping/low power mode on nRF5340

user73356 — Tue, 19 Apr 2022 00:39:20 GMT

A bit more info: I tried adding these to my spm.conf file:

CONFIG_PM=y

CONFIG_PM_DEVICE=y

With CONFIG_PM_DEVICE in there it fails to build. With just CONFIG_PM, it works - but it does not change anything about the behavior I described above.