nRF52832 drawing high current (0.1 mA) in system off mode

[antarctic]

I have an Adafruit nRF52832 board, and I'm trying to minimize power consumption by putting it in system off mode. It is attached to a breadboard, and none of the pins are connected to anything. 

I have the following code: 

int main(void){
NRF_POWER->SYSTEMOFF = 1;

for(;;){}
}

I downloaded this to my board, disconnected it from USB, and connected it to a battery with a multimeter. The current reading gives 0.1 mA, but the nRF52832 spec says that system off mode is supposed to yield a current consumption of 300 nA. 

I've also tried enabling the DCDC power regulator with NRF_POWER->DCDCEN = 1; which didn't change the current. 

I'm a bit confused as to what could be causing this, as I'm not doing anything outside of the code snippet posted. 

Thanks for any help. 

[Håkon Alseth]

Hi,

 

int main(void){
NRF_POWER->SYSTEMOFF = 1;

for(;;){}
}

Just an fyi: I usually add a delay of around 1 second, so that I can see when the device wakes up, based on the current consumption. Just for visualization reasons.

I downloaded this to my board, disconnected it from USB, and connected it to a battery with a multimeter. The current reading gives 0.1 mA, but the nRF52832 spec says that system off mode is supposed to yield a current consumption of 300 nA. 

Which multimeter do you use? Do you have one that has a bit of a better resolution (ie. < 100 uA) ?

 

Kind regards,

Håkon

[antarctic]

Hello, 

I should have specified that my multimeter also has a uA option, and that the reading is usually around 106-112 uA. I'll try adding the delay in future tests. 

[Håkon Alseth]

Which nRF52 board specifically are you testing on? If there's other sensors on the board, they will add to the overall current consumption, and any GPIOs connected to the sensor(s) should be in a defined state, either pulled to idle via. the internal pull-resistors, or externally.

 

Kind regards,

Håkon