nRF52 does not enter system off

RE: nRF52 does not enter system off

Aj-falcon — Mon, 18 Oct 2021 21:22:21 GMT

Another way to quickly check 'system off' during development is to put an LED on after that statement. Within SEGGER IDE, if JTAG is connected, the LED will turn on, else if the JTAG is disconnected, LED won't turn on. (Reset the board after disconnecting the JTAG from the SEGGER IDE to restart the execution from the beginning).

RE: nRF52 does not enter system off

Susheel Nuguru — Thu, 08 Mar 2018 12:32:41 GMT

Yes, you are right, Like Pratyush said, we saw that connecting the chip to RTT terminal itself will pull the chip into debug mode.

RE: nRF52 does not enter system off

gnf — Thu, 08 Mar 2018 12:26:00 GMT

I just stumbled on this thread as I have the same issue. I can confirm that connecting with RTT Viewer will wake the chip up from power off mode. I am testing this on the hrs example which also emits a fatal error after APP_ADV_TIMEOUT_IN_SECONDS, where it wants to go to power off mode, if RTT Viewer is still connected.

RE: nRF52 does not enter system off

Pratyush Dave — Mon, 23 Oct 2017 14:51:29 GMT

I believe using the RTT terminal from a PC will also put the chip in debug mode!

RE: nRF52 does not enter system off

Susheel Nuguru — Thu, 01 Dec 2016 15:28:21 GMT

No, it is in debug mode if you started debugger or explicitly made chip to go to debug mode by controlling the SWD lines after the chip went to SystemOFF

RE: nRF52 does not enter system off

Jarmo — Thu, 01 Dec 2016 14:09:49 GMT

It might be the case. I am using RTT to see debug printings, so does that mean the system is in debug mode and thus emulates system off?

RE: nRF52 does not enter system off

Susheel Nuguru — Thu, 01 Dec 2016 13:56:29 GMT

did you get to check if this was the case for you Jarmo?

RE: nRF52 does not enter system off

Susheel Nuguru — Wed, 30 Nov 2016 19:11:44 GMT

I am pretty sure you are seeing this in debugger. In debug mode system off does not work. Instead, emulated system off is used which does not go to deep sleep and the CPU continues to run. But the wakeup source will reset the chip in both emulated system off and normal system off. We added this feature for debugging. One way to verify that your system off feature is working in debugger is to trigger the wakeup source and see if it has reset the chip.

Also it is important to have a while(1); after the triggering the system off. Else in debug mode, since the CPU continues to run, it will cause some hardware fault because it will start executing something which it is not supposed to.

Please read product specifications for more info at infocenter.