nRF9160 excess power consumption after RTT disconnect

RE: nRF9160 excess power consumption after RTT disconnect

helsing — Thu, 02 Oct 2025 07:00:16 GMT

Hi Jordan, sorry for the delay.

[quote user="JordanYates"]can only be recovered through a pin reset.[/quote]

The recommendation is to use pin reset or power cycle in the production line. This has been recommended in order to ensure that the SoC is not in any state with higher power consumption when leaving the production line.

However, you can try with other types of reset, for example

$ nrfutil device reset --reset-kind RESET_SOFT

Hopefully, a soft reset works sufficently for everyday development.

RE: nRF9160 excess power consumption after RTT disconnect

JordanYates — Sat, 13 Sep 2025 02:38:52 GMT

So the answer is that requesting power via `CxxxPWRUPREQ` fundamentally changes the internal power consumption of the SoC in a way that is not reversed by reverting the value written to `CxxxPWRUPREQ`, and can only be recovered through a pin reset.

RE: nRF9160 excess power consumption after RTT disconnect

helsing — Fri, 12 Sep 2025 09:37:41 GMT

Hi Jordan, sorry for the delay.

When using the read function (for readregs, memrd etc.) in either nrfutil or nrfjprog, debug mode is then started and the cpu is halted. After reading out the data a reset is necessary in order to exit debug mode and start running again(with lower power consumption).

More details on this can be found in the Debug interface mode section:

RE: nRF9160 excess power consumption after RTT disconnect

JordanYates — Sat, 19 Jul 2025 01:25:51 GMT

This issue still exists 3 years later with the nRF9151 and the nrfutil tools.
This is a power trace of running the `nrfutil device core-info` command.
The one improvement is that `nrfutil device reset` does return the device back to the lower power consumption, where `nrfjprog -r` did not.

RE: nRF9160 excess power consumption after RTT disconnect

JordanYates — Wed, 27 Apr 2022 23:48:06 GMT

Has there been any progress on this?
I am still seeing the issue on the Thingy91 board with the latest version of the SEGGER tools (7.64c).

The only thing that brings the current consumption back down is power cycling the device.
Even running `nrfjprog -r` on a device is enough to start the higher current consumption.

RE: nRF9160 excess power consumption after RTT disconnect

JordanYates — Wed, 16 Mar 2022 21:40:32 GMT

No problem, I can also verify that the same problem occurs when using the Thingy91 board.

I am also testing on MacOS.

RE: nRF9160 excess power consumption after RTT disconnect

helsing — Wed, 16 Mar 2022 14:25:07 GMT

Hi Jordan, sorry for keeping you waiting.

I am trying to reproduce the issue. I will keep you posted.

RE: nRF9160 excess power consumption after RTT disconnect

JordanYates — Fri, 11 Mar 2022 22:49:44 GMT

It is a custom board. The reset is included in the SWD interface (as proven by `nrfjprog -r` resetting the board).
Disconnecting from RTT should not trigger a reset though, so I'm not sure how this is relevant.

RE: nRF9160 excess power consumption after RTT disconnect

helsing — Fri, 11 Mar 2022 15:19:43 GMT

Is this the DK or a custom board? If this is a custom board, did you include reset in the SWD interface?

RE: nRF9160 excess power consumption after RTT disconnect

helsing — Fri, 11 Mar 2022 09:50:56 GMT

Hi Jordan,

Thank you for reporting this. Just letting you know I am looking into it and will get back to you soon.

Best regards,

Håkon