Power Consumption of nRF5340

RE: Power Consumption of nRF5340

Michael Nemanov — Fri, 15 May 2020 19:34:47 GMT

Good question. Maybe one of Nordic's engineers can help.

Regards,
Michael.

RE: Power Consumption of nRF5340

Adrian Eggenberger — Fri, 15 May 2020 12:45:14 GMT

Hi Michael

With your tipp I was able to reproduce the behavior from you and got the same 15uA. Is the 15uA an explainable value? From the datasheet I would expect a deeper value, right? Maybe a limitation of the development board or the engeneering A chip?

Regards Adrian

RE: Power Consumption of nRF5340

Michael Nemanov — Mon, 11 May 2020 16:51:26 GMT

Hi Adrian,

I'm not 100% sure how to determine the PDK/SDK version but the git branch I've started from is v2.1.99-ncs1.

As mentioned above, the current was measured using jumper P22.

I've used the general Zephyr PM example (ncs/zephyr/samples/subsys/power/device_pm).

In that example I had to:
1. Disable the network core.
2. Disable the UART completely (CONFIG_SERIAL=n in prj.conf) or at least disable the Rx task (NRF_UARTE0->TASKS_STOPRX = 1; somewhere in the source code).

Regards,
Michael.

RE: Power Consumption of nRF5340

Adrian Eggenberger — Mon, 11 May 2020 15:32:46 GMT

I had some issues with the nRF5340 current consumption today. In fact I'm not able to get a lower current than a 3mA. May I ask you a few questions?
- What version of the nRF Connect SDK did you use?
- How did you measure the current?
- What which example did you finally manage it?
- What version of the nRF5340 PDK did you use?

RE: Power Consumption of nRF5340

Michael Nemanov — Sun, 08 Mar 2020 12:27:31 GMT

"NRF_UARTE0->TASKS_STOPRX = 1;" Indeed lowers the sleep current but only to 180 uA, not the 15uA if the UART is disabled in proj.conf.
Anyway its good enough for me at the moment 🙂

Thanks for all the help Håkon.

Regards,
Michael.

RE: Power Consumption of nRF5340

Håkon Alseth — Fri, 06 Mar 2020 08:39:14 GMT

Glad to hear that the current is down!

[quote user="Michael Nemanov"]Setting CONFIG_SERIAL=n reduces current to 15 uA when idle.
Is there any way to keep the serial and the low current (when the UART is not transmitting / receiving)?[/quote]

Its the receiver part that is causing the added current. You can theoretically stop the UARTE RX, and later on enable it:

NRF_UARTE0->TASKS_STOPRX = 1;

Kind regards,

Håkon

RE: Power Consumption of nRF5340

Michael Nemanov — Thu, 05 Mar 2020 13:22:32 GMT

Thanks!

Setting CONFIG_SERIAL=n reduces current to 15 uA when idle.
Is there any way to keep the serial and the low current (when the UART is not transmitting / receiving)?

Regards,
Michael.

RE: Power Consumption of nRF5340

Håkon Alseth — Thu, 05 Mar 2020 12:44:58 GMT

Try power cycling the board and see if the current consumption drops.

Also, try adding CONFIG_SERIAL=n to your prj.conf (or disabling it in menuconfig for your specific build)

Kind regards,

Håkon

RE: Power Consumption of nRF5340

Håkon Alseth — Thu, 05 Mar 2020 12:20:01 GMT

Hi Michael,

[quote user="Michael Nemanov"]So assuming I have no code I want to run in the network core I could do:
NRF_RESET->NETWORK.FORCEOFF = RESET_NETWORK_FORCEOFF_FORCEOFF_Hold;
from the application CPU and it will put the network core to sleep?[/quote]

That is correct. Remember to power cycle the nRF after programming, so that the debugger session is guaranteed to be closed (and MCU is not halted)

Kind regards,

Håkon

RE: Power Consumption of nRF5340

Michael Nemanov — Thu, 05 Mar 2020 11:55:24 GMT

[quote userid="88450" url="~/f/nordic-q-a/58734/power-consumption-of-nrf5340/238248"]NRF_RESET->NETWORK.FORCEOFF = RESET_NETWORK_FORCEOFF_FORCEOFF_Hold;[/quote]

OK, this drops the current from the above mentioned 3.28mA to 2.22 mA. Is this expected? (I saw no data sheet to reference against).

RE: Power Consumption of nRF5340

Michael Nemanov — Thu, 05 Mar 2020 11:26:45 GMT

Hi Håkon,

Thanks for the quick reply 🙂

So assuming I have no code I want to run in the network core I could do:
NRF_RESET->NETWORK.FORCEOFF = RESET_NETWORK_FORCEOFF_FORCEOFF_Hold;
from the application CPU and it will put the network core to sleep?

Regards,
Michael.

RE: Power Consumption of nRF5340

Håkon Alseth — Thu, 05 Mar 2020 11:15:43 GMT

Hi Michael,

This line:

https://github.com/NordicPlayground/fw-nrfconnect-zephyr/blob/master/boards/arm/nrf5340_dk_nrf5340/nrf5340_cpunet_reset.c#L55

Will release the network CPU, and if there's no program in the network core, it'll just run, causing a higher power consumption.

You can either put the core back to sleep, or compile a simple program that goes straight to wfe (or k_cpu_idle() when using the rtos API).

If you go to ncs/zephyr/samples/basic/blinky/ and modify the main.c to hold only "while(1) k_cpu_idle();" and build/flash for the network core:

west build -b nrf5340_dk_nrf5340_cpuapp

Could you try this and see if the current goes down?

Note that since you have UART output, you should see approx. 0.5 mA current consumption due to the UART RX being active. if you disable serial (CONFIG_SERIAL=n), it should go lower.

Kind regards,

Håkon