SDK v15.3.0 vs. v16.0.0 Power Consumption

RE: SDK v15.3.0 vs. v16.0.0 Power Consumption

Stian Røed Hafskjold — Mon, 10 Feb 2020 14:00:46 GMT

SDK 15.3.0 comes with nrfx version 1.6.2, and SDK 16.0.0 comes with nrfx version 1.8.0. Doing a diff between the two tags, and looking at the uarte.c file, shows that they made the following changes:

https://github.com/NordicSemiconductor/nrfx/compare/v1.6.2...v1.8.0#diff-b83040199a6d53ba3c5768b6942c6e2aL587 (maybe wait a little bit for the code to load)

So basically, the old UART driver in nrfx version 1.6.2, when the transaction stopped (receiving the ENDTX event), just cleared the event, and did nothing more. This is not the correct way of handling the ENDTX event, according to the PS. After the ENDTX event is received the UART transaction is properly stopped by calling the STOPTX task, and then waiting for the TXSTOPPED event.

In other words, logging in the older versions of the SDK consumed a lot of current because the UART transation was never stopped.

You can probably add the lines in the git diff I linked to above to SDK 15.3.0 to get the current consumption down.

RE: SDK v15.3.0 vs. v16.0.0 Power Consumption

Akash Patel — Thu, 06 Feb 2020 22:38:30 GMT

Hi Stian,

Thanks, I was able to disable logging in both examples and measure about 2 uA of current and see about 70 uA of average current.

[quote userid="4556" url="~/f/nordic-q-a/57453/sdk-v15-3-0-vs-v16-0-0-power-consumption/233027"]they have been able to reduce the high current consumed by the UARTE driver in the nrfx version that comes with SDK 16.0.0[/quote]

Do you have more information on this? Is there something similar that can be done to reduce the UARTE power consumption in SDK v15.3.0?

Regards,

Akash Patel

RE: SDK v15.3.0 vs. v16.0.0 Power Consumption

Stian Røed Hafskjold — Thu, 06 Feb 2020 11:12:10 GMT

Hi, the high idle current you get when using SDK 15.3.0 and earlier is because logging is enabled by default. Logging is also enabled by default in SDK 16.0.0, but it seems like they have been able to reduce the high current consumed by the UARTE driver in the nrfx version that comes with SDK 16.0.0. To get similar idle current, ~2.0 µA, in both SDK 15.3.0 and SDK 16.0.0 heart rate examples, disable logging by setting the NRF_LOG_ENABLED define to 0 in sdk_config.h.