[System Power off]

[annapalu]

Hi all, i use the function sd_power_system_off() to put the micro in system off. First question is about the the type of system off. There are different type of system OFF:

IOFF_RAMOFF_RESET System OFF,  No RAM retention,   Wake on reset     0.7 μA
IOFF_RAMOFF_GPIO System OFF,   No RAM retention,   Wake on GPIO      1.2 μA
IOFF_RAMOFF_LPCOMP System OFF, No RAM retention,   Wake on LPCOMP    1.9 μA
IOFF_RAMOFF_NFC System OFF,    No RAM retention,   Wake on NFC field 0.7 μA
IOFF_RAMON_RESET System OFF,   Full RAM retention, Wake on reset     1.0 μA

How can i understand what power off type i'm using? Second question i see a consumption of 0.5 uA, but sometimes it increase to 1.5/ 2 uA, someone have any idea about the reason?

Thanks, anna

[Jørgen Holmefjord]

Hi,

The current consumption in system off mode is determined by the configured RAM retention and wakup sources. If you have not configured any wakeup sources, you the only way to wake from system off is by triggering a reset. The wakeup sources and reset behavior is described in the product specification of nRF52832 in the infocenter.

Is there anything special going on when the current increase, or is your device in any special states? Have a look at this thread about minimizing current consumption on nRF51 devices. Most of the methods also apply to nRF52 devices.

Best regards,

Jørgen

[annapalu]

Hi, thanks for the answer. I set the Gpio button to wake up the device, and it works correctly, when i press button the device wake up and there is a reset of my board. As long as i press the button, i aspect that the system stay in power off mode. I'm sure that there isn't a wakeup from system off, but seems that there is something that runs that cause the increase of consumption, when the system stays in system off.

About the RAM retention when i can find the type to set it, is there an example?