nRF52840 peripheral_uart low power NCS 1.3.0

[Vojislav]

Hi,

I am working with nrf52840dk and using a peripheral_uart example from NCS v1.3.0. and the problem that I am currently having is that I cannot get it to low power. At the moment I have power consumption ~500nA and I suppose this is from UART and Jlink programming pins. 
In the previous release of NCS v1.2.0, I have managed to turn off UART with the Power Management module, but for some reason, this is not working in the new release. More about my previous development is in this issue: nRF52 NCS power consumption. 

A also noticed that on the master branch of ncs-sdk peripheral_uart example has changed a lot.

My question is what is the best way to configure peripheral_uart example to low power?

Best regards,
Vojislav. 

[Stian Røed Hafskjold]

Hi, so you were able to turn on and off UART in NCS 1.2.0 but when using NCS 1.3.0 you still see high current consumption after turning off the UART. I think one change they made in NCS 1.3.0 is that all UART peripherals are turned on by default. So maybe the current consumption you are seeing is because of UART1 being active (assuming you are using UART0 for NUS and logging).

Try to add an overlay file (nrf52840dk_nrf52840.overlay) to the project root folder which completely disables the UART1 peripheral:

&uart1 {
   status = "disabled";
};

You might have to clean/delete the build folder before recompiling.

[Vojislav]

Dear Stian,

Thanks for your reply, the issue is now solved! While focusing on configuration and UART0 I did not check other peripherals. 

Best regards,
Vojislav.