nRF only mode on nRF52840DK

RE: nRF only mode on nRF52840DK

Jørgen Holmefjord — Tue, 12 Jan 2021 14:24:15 GMT

Hi,

Sorry for the slow response on this matter. I'm not able to build the application, as it seems to include some custom drivers.

If you have not yet resolved this issue, can you please post the full project, including the custom driver implementations?

Best regards,
Jørgen

RE: nRF only mode on nRF52840DK

krajiiva — Wed, 09 Dec 2020 21:11:13 GMT

I measure the current that goes through the P21 to the board. I use the nRF5 SDK 16.0.0 with the SDK for Mesh 4.2.0. I have extended the example of the BLE Mesh sensor model. The sensor server uses timers, the SAADC, TWI and several GPIO's. But if I comment all this out (including the initialization and the start of the BLE mesh) and just run "nrf_pwr_mgmt_run()" in the main, I still have a power consumption of about 1.4mA. The only thing that is still on is the RTC (defined in my code as sleep timer). Attached you can find the main program which gives me a current consumption of 1.4mA. I have read that NRF_LOG_ENABLED can consume power, because this causes the UART to be on. In "sdk.config" the macro is and was never enabled. Nevertheless the main uses functions from "log.h". How can this be? Is it possible that this is the cause of the remaining 1.4mA?
Do I have to configure something on the DK with the solder bridges to get further down with the consumption?

Thanks already.

Kind regards.
devzone.nordicsemi.com/.../050870.main.c

RE: nRF only mode on nRF52840DK

Jørgen Holmefjord — Wed, 09 Dec 2020 13:01:28 GMT

Hi,

How do you measure the current? Do you measure current on P22/P23, or do you measure the current going into the board through P21? Current on P22/P23 pins are for the nRF power domain only, it does not include the current from interface MCU, LEDs, etc.

What application are you running on the DK, and which SDK version are you using? Calling nrf_pwr_mgmt_run() will not necessarily give you low current consumption, this depends on which modules are enabled/running in the background. 1.4 mA (given that this is consumed by the nRF itself), sounds like the EasyDMA current. This is often enabled by UARTE in RX mode or SAADC peripheral enabled.

Best regards,
Jørgen