case about low power mode rtt not disconnect

[peter.min]

Hi,

1.Mode B prevents RF9160 from entering low power consumption. How to disconnect RTT from nRF9160 module in mode B

2. In normal mode A, disconnect RTT from the  computer J-Link RTT Viewer V7.82:

3. Abnormal mode B, RTT is not disconnected from the  computer J-Link RTT Viewer V7.82:   RTT disconnects by disconnecting SWDIO and SWCLK

Thank you for all your assistance.
Kind regards,
Peter.Min

[Charlie]

Hi Peter,

I am not sure if I understand your problem, can you elaborate on it?

1) Do modes A and B have the same design? so only mode B has this issue? if so, do you have tested more models?

2) The picture seems to show that mode B has a problem connecting with the RTT viewer, but why do you say you have a problem disconnecting mode B?

3) In order to achieve low power for your device, you need to disable the backend like RTT or serial as log output, like the sdk-nrf/overlay-low-power.conf at v2.1.2 · nrfconnect/sdk-nrf (github.com) does.

Best regards,

Charlie

[peter.min]

Hi Charlie,

1.The code of mode A or mode B is the same

2. The RTT viewer disconnects in different ways:

Mode A uses the shortcut key F3 to disconnect,

Mode B brutally unplug the hardware directly

3.I know that overlay files can close the rtt log

I would like to know if there is an api to turn off the rtt log

4.The above phenomenon occurred when the nRF9160 low power program was tested on the ncs platform, and the same phenomenon can be repeated on the 52 platform low power program.

Thank you for all your assistance.
Kind regards,
Peter.Min

[Charlie]

Hi Peter,

1) How do you identify mode B is not "disconnected"? In my opinion, the fact is that it is already physically "disconnected".

2) Could you explain how you prepare "nRF9160 low power program"? When you enable log and its backend(like RTT), you cannot really achieve low power for your device. It will reserve some resources for logging, and you cannot turn off them at run time, so the low-power firmware is built with overlay-low-power.conf at compiling time.

Best regards,

Charlie