Adafruit Feather nrf52840 Express Power Usage

RE: Adafruit Feather nrf52840 Express Power Usage

Edvin — Tue, 05 Nov 2024 14:18:13 GMT

Try removing the neopixel from the board and see if it stops drawing the current.

Best regards,

Edvin

RE: Adafruit Feather nrf52840 Express Power Usage

Seppe Soete — Fri, 01 Nov 2024 14:08:45 GMT

None of the LED's are lighting up.
The main components that can be taking up power according to me are the voltage regulator, the pullup resistor on the EN-pin (link to the board's schematic) and the so-called "neopixel" (an WS2812B RGB led that's soldered onto the board by default and supposedly has a fairly high quiescent current draw)

RE: Adafruit Feather nrf52840 Express Power Usage

Edvin — Fri, 01 Nov 2024 13:50:48 GMT

This is what I measure when building for the nRF52840DK with the project that you sent. I used the prj.conf.old file (renamed it prj.conf).

I also tried renaming your boards\adafruit_feather_nrf52840.overlay to boards\nrf52840dk_nrf52840.overlay, but I had to remove the aliases: reg1, because it didn't compile (it is not defined in the DK's .dts files).

And the current consumption was identical. So either it is related to the reg1, or there is some other component on the board that is drawing power. Are any of the LEDs lighting up?

BR,
Edvin

RE: Adafruit Feather nrf52840 Express Power Usage

Seppe Soete — Fri, 01 Nov 2024 11:18:14 GMT

devzone.nordicsemi.com/.../system_5F00_off_5F00_sample.zip

This is the sample I have been using. It is taken straight from the zephyr samples, but with my prj.conf and overlay file.

I know of the limitations of using a multimeter, but both my own multimeter as well as the benchtop multimeter they have at my university lab (which has graphing functionality) show the ~400uA measurement as a stable baseline, with some peaks higher than that.

On the DK, measuring only the chip, this sample should give very low power consumption. I suspect the issue I have is specific to my board.

RE: Adafruit Feather nrf52840 Express Power Usage

Edvin — Fri, 01 Nov 2024 09:22:34 GMT

Ok. Feel free to upload any sample that will reproduce what you are seeing.

Also, you can't reliably trust readings done on a multimeter, because the current consumption is not stable. For most parts, it is very little current, but there will be some spikes that are charging some capacitors. So depending on how the multimeter works, some may sample at random times, some may use the peaks only. So you need to either use an oscilloscope, or the Power Profiler Kit II, which will give you a graph, and more accurate current measurements.

If you upload a sample, I can measure it running on a DK. I don't know how it behaves on your 3rd party board, or what other components that are present on that board that may draw current. On the DK it is possible to isolate the reading to only measure the chip, and bypass the LEDs and the debugger and the other components on the board.

Best regards,

Edvin

RE: Adafruit Feather nrf52840 Express Power Usage

Seppe Soete — Thu, 31 Oct 2024 12:15:02 GMT

I am measuring the current by putting a multimeter in series with the board (which is being powered via the BAT pin)

I don't think I can send you the full application, but I get the same results with the sample in samples/boards/nordic/poweroff with my overlay and prj.conf (with CONFIG_POWEROFF=y added, CONFIG_SERIAL set to y and uart0 in my overlay re-enabled for compatibility, as the sample manually disables the serial port). So if possible I would like to use that sample as a basis for this.

RE: Adafruit Feather nrf52840 Express Power Usage

Edvin — Thu, 31 Oct 2024 08:38:33 GMT

Can you zip and send me the application folder that you are currently testing on?

And how do you measure the current?

Best regards,

Edvin

RE: Adafruit Feather nrf52840 Express Power Usage

Seppe Soete — Wed, 30 Oct 2024 15:03:08 GMT

I'm building with -b adafruit_feather_nrf52840/nrf52840, so that should be for the adafruit board file and not the dk AFAIK

RE: Adafruit Feather nrf52840 Express Power Usage

Edvin — Wed, 30 Oct 2024 14:58:01 GMT

[quote user="Seppe Soete"]I enabled SPI and I2C because in some places I read that disabling drivers could potentially prevent peripherals from being put into a low-power state.[/quote]

The only way I can think of is on a DK, if you have an external flash chip that you don't tell to go to low power mode, but that should be handled automatically by the board files and NCS. Besides, it doesn't look like this board has an external flash chip.

Are you building for the adafruit board file, or are you using the nrf52840dk_nrf52840 board files?

Best regards,

Edvin

RE: Adafruit Feather nrf52840 Express Power Usage

Seppe Soete — Wed, 30 Oct 2024 14:47:38 GMT

Thanks for your response, Edvin!

I enabled SPI and I2C because in some places I read that disabling drivers could potentially prevent peripherals from being put into a low-power state. With them enabled/disabled I minimal to no difference in power consumption so that's why they're still on. I currently do not use either of them.

I have indeed noted that with the RTT terminal open it does increase power consumption, my ~400uA measurement is with the debugger disconnected & after a power cycle.

The application runs as expected without any errors in the log.

RE: Adafruit Feather nrf52840 Express Power Usage

Edvin — Wed, 30 Oct 2024 14:42:58 GMT

Hello,

Any particular reason why you enabled SPI and I2C? Does the current go down if you disable them in your prj.conf? Did you add them to your application, and used them before going to system off?

And for debugging purposes, if you open an RTT Terminal, the power consumption will go up, but does the log say anything about any errors, or does it run as expected?

Best regards,

Edvin