nRF54L15 power consumption in sleep

RE: nRF54L15 power consumption in sleep

Dilshod — Wed, 04 Dec 2024 12:12:18 GMT

How do you enable CONFIG_PM? nrf54l15 does not have HAS_PM.

RE: nRF54L15 power consumption in sleep

Simonr — Wed, 20 Nov 2024 09:19:12 GMT

Sorry, I guess I wasn't clear in my lasst reply, but we don't yet have power management for the FLPR available yes, and it is something that will be coming down the road. For now you will have to turn off the FLPR core entirely if you want to achieve the lowest possible current consumption.

Best regards,

Simon

RE: nRF54L15 power consumption in sleep

Marcel Graber — Tue, 19 Nov 2024 14:03:06 GMT

Hi Simon,

Ah ok, thanks for your feedback,

But just a followup to fix my project:

How can I set the FLPR Core to sleep in Zephyr/NCS? (seems, that Zephyr doesn't do this, even if the FLPR is in k_sleep... endless loop and PM_DEVICE=y is set)
Does the FLPR needs a explicit command to set it to sleep in code?

Best regards,

Marcel

RE: nRF54L15 power consumption in sleep

Simonr — Tue, 19 Nov 2024 12:51:19 GMT

Hi Marcel

So, the FLPR core isn't really a low power core here, but rather a fast lightweight one. It won't be comparable to the app core I'm afraid, even when idle sleep is eventually implemented. You're comparing a device running on 1.8V and one running on 3V here after all.

Best regards,

Simon

RE: nRF54L15 power consumption in sleep

Marcel Graber — Mon, 18 Nov 2024 13:22:34 GMT

Hi Simon,

Sure, the FLPR core is running, because I wanted to test the LowPower Features and possibilities of this new RISC-V CoProcessor.

The project is setup as a multi-image build, you find two firmwares (flpr/src/main.c) (main/src/main.c) and both firmware should go to Zephyr-auto-sleep (PM_DEVICE enabled and endless loop with k_sleep)

But as this was only a test for the nRF54 and not a productive need, I will wait, till you have some sample code in NCS.

Best, Marcel

RE: nRF54L15 power consumption in sleep

Simonr — Mon, 18 Nov 2024 12:48:54 GMT

Hi Marcel and Bryn

What core are you building for here Marcel, the app core or the FLPR core? The FLPR core does not go into the idle mode by default, and this current consumption could seem like the FLPR is running. This is done by building either for the cpuapp or cpuflpr targets in VS Code. Check out the nRF54L series development guide available here for reference.

Best regards,

Simon

RE: nRF54L15 power consumption in sleep

Marcel Graber — Mon, 18 Nov 2024 09:22:07 GMT

When I enable the CONFIG_PM, I get a configuration warning. Seems something with my Out of Tree build setup is not correct

RE: nRF54L15 power consumption in sleep

BrynMorgan — Mon, 18 Nov 2024 09:02:11 GMT

I had the same issue with bricking the dev kit after disabling the SWD switches. I had to revert back to Board Configurator 0.3.7 to get it working again. See my post here: nRF54L15-PDK cannot connect after attempt to change Board Configurator settings

I used a custom project, which is essentially just a BLE advertising beacon every 1s, sleeping in between.

Also, one other config option to enable in your prj.conf would be:

CONFIG_PM=y

I have this enabled in mine.

RE: nRF54L15 power consumption in sleep

Marcel Graber — Mon, 18 Nov 2024 08:55:03 GMT

thanks for your tips, yes I also used the Board Configurator to set the switches. BTW, After I did turn off the SWD, I did not get the DK back to work ;-(

Which project in the NCS did you use for your tests?

RE: nRF54L15 power consumption in sleep

BrynMorgan — Mon, 18 Nov 2024 08:45:34 GMT

Sorry, I see that in the boards folder now. Are you certain it's actually applied to the build? In my build config I had to manually point it to the overlay file, it didn't seem to automatically detect it.

I achieved ~3-4uA sleep current by using the cpuapp build configuration. Perhaps try that?

Also I used the Board Configurator App to disable the UART/SWD/GPIO switches on the dev kit. According to the dev kit data sheet, leaving these active leaks current.

RE: nRF54L15 power consumption in sleep

Marcel Graber — Mon, 18 Nov 2024 08:23:22 GMT

Hi Bryn,

when you look at the project, you see that I already disabled UART and ADC in an overlay. ;-)

RE: nRF54L15 power consumption in sleep

BrynMorgan — Mon, 18 Nov 2024 08:12:26 GMT

I had this same issue. With Dev kits, their Devicetree is configured by default to enable most/all peripherals (ADC, GPIO, UART etc).

This is done within the ncs/zephyr/boards configuration .dtsi file by assigning status = "okay" to those peripherals.

What you want to do is create an overlay of the dev kit and disable those peripherals by assigning status = "disabled"

This should reduce your current consumption in sleep state.

Zephyr should automatically be putting the peripherals to sleep however needs additional sleep configuration in the devicetree/configuration files which the Dev kit files do not contain by default.