High power consumption in deep sleep mode in nRF5340

[Jithin A]

Hi,
I am trying to put the nRF5340 to deep sleep, my application is built with TF-M (_ns).
When tested with the sample system_off application (built without TF-M) I observe 0.25uA.
If I integrate the same into my project, I observe 0.25mA. I assume the device is not entering to deep sleep, am I missing any configuration here? or why I am observing this huge difference?

Below is the prj.conf file used in my project.

CONFIG_BUILD_WITH_TFM=y
CONFIG_TFM_PROFILE_TYPE_NOT_SET=y
CONFIG_TFM_IPC=y
CONFIG_NRF_SPIM3_SECURE=y
CONFIG_NRF_TWIM2_SECURE=y
CONFIG_NRF_TIMER2_SECURE=y
CONFIG_NRF_PWM0_SECURE=y
CONFIG_NRF_TIMER1_SECURE=y
CONFIG_NRF_PWM1_SECURE=y
CONFIG_NRF_GPIOTE0_SECURE=y
CONFIG_ADC=y
CONFIG_PM=y
CONFIG_PM_DEVICE=y

Below is the code snippet of how I am putting the device to deep sleep in non-secure.

pm_state_force(0u, &(struct pm_state_info){PM_STATE_SOFT_OFF, 0, 0});

Please guide me through this
Thank you in advance.

[Vidar Berg]

Hi,

I suggest you place a breakpoint at this line: https://github.com/nrfconnect/sdk-zephyr/blob/main/soc/arm/nordic_nrf/nrf53/power.c#L22 to verify that it is actually being called. You may also want to verify the IO configuration at this point. The IO configurations are retained in system OFF and a floating input will typically lead to a leakage current of around 200 uA.

Best regards,

Vidar

[Jithin A]

Hi, 

I have set the breakpoint as mentioned, I see it is not coming to the break point. Do I need to call the API explicitly?

For now, to put the device into sleep mode I am calling the below API.

pm_state_force(0u, &(struct pm_state_info){PM_STATE_SOFT_OFF, 0, 0});

 

[Vidar Berg]

Hi,

No, you should not have to call the API directly. You do however need to let the program enter the idle thread. For instance, by calling k_sleep() after pm_state_force(0u, &(struct pm_state_info){PM_STATE_SOFT_OFF, 0, 0});

[Jithin A]

Thanks for the quick response, 

Below is how we have implemented:

pm_state_force(0u, &(struct pm_state_info){PM_STATE_SOFT_OFF, 0, 0});

/* Now we need to go sleep. This will let the idle thread runs and
 * the pm subsystem will use the forced state. To confirm that the
 * forced state is used.
 */
k_sleep(K_SECONDS(2U));

We have also TF-M (secure) application running along with non-secure.

Is it ok to leave the TF-M application as is or do we need to configure in TF-M to indicate the MCU to go to sleep mode?

[Vidar Berg]

The TF-M should not have any effect on this. You can also build the system_off sample for nrf5340dk_nrf5340_cpuapp_ns to confirm this. 

Would you mind trying to debug the system_off sample to see if the breakpoint gets reached then?