Going to Low power mode and coming back in nrf52832

[mostafa]

Hi Nordic Support Team,

I try to go to low power mode and coming back but can't at all.

I have used the example pwr_mgmt in sdk 12.3.0, but when try to use its function

"nrf_pwr_mgmt_shutdown(NRF_PWR_MGMT_SHUTDOWN_GOTO_SYSOFF);"

in my code after compile I get following error in linking sequence:

.\_build\nrf52832_xxaa.axf: Error: L6218E: Undefined symbol nrf_pwr_mgmt_shutdown (referred from main.o).

I have also copied all definitions from the example sdk config file to my config file.

I have also tried to go to low power mode by following lines but it doesn't work after programming the chip:

"

 NRF_POWER->TASKS_LOWPWR = 1;
NRF_POWER->SYSTEMOFF = POWER_SYSTEMOFF_SYSTEMOFF_Enter;
NRF_POWER->TASKS_CONSTLAT = 1 ; 

"

I found that by using this function "sd_power_system_off()" it is possible but compiler says that can't find it.

Thanks for your help.

[mostafa]

Hi again,

I am not using SoftDevice, so I could use  NRF_POWER->SYSTEMOFF = POWER_SYSTEMOFF_SYSTEMOFF_Enter; 

to go to SYS OFF but it comes back on any button press event. How I can define a specific button for it to come back from

SYS OFF?

[haakonsh]

Hey Mostafa, 

Have you enabled the power management module in sdk_config.h?

Cheers,

Håkon.

[mostafa]

yes I enabled it in sdk_confi.h, but couldn't use it . so I used 

NRF_POWER->SYSTEMOFF = POWER_SYSTEMOFF_SYSTEMOFF_Enter; 

but it comes back from low power mode with any trigger on any GPIO!!!

[haakonsh]

From GPIO — General purpose input/output:

Pins can be individually configured, through the SENSE field in the PIN_CNF[n] register, to detect either a high level or a low level on their input.

When the correct level is detected on any such configured pin, the sense mechanism will set the DETECT signal high. Each pin has a separate DETECT signal, and the default behaviour, as defined by the DETECTMODE register, is that the DETECT signal from all pins in the GPIO Port are combined into a common DETECT signal that is routed throughout the system, which then can be utilized by other peripherals, see Figure 1. This mechanism is functional in both ON and OFF mode.

See the following peripherals for more information about how the DETECT signal is used:

• POWER: uses the DETECT signal to exit from System OFF.

 

Fortheremore:

The input buffer of a GPIO pin can be disconnected from the pin to enable power savings when the pin is not used as an input, see Figure 1. Inputs must be connected in order to get a valid input value in the IN register and for the sense mechanism to get access to the pin.