nrf9160 SPI power consumption

RE: nrf9160 SPI power consumption

Tron — Fri, 07 Feb 2020 06:56:44 GMT

Found the solution here, the source code set the polarity of the SPI clock to low on active, but it was the opposite. Reverting the polarity did the trick.

RE: nrf9160 SPI power consumption

Tron — Thu, 06 Feb 2020 09:48:42 GMT

After painfully debugging for a forthnite, I come to the following conclusion:

The flash is not the issue, it's the SPI.

In a test I wrote from the MOSI directly to the MISO, leaving the flash out of the equation, and it seems it's the SPI device that's causing the havoc.

As long as I leave the SPI pins alone, the current stays low (around 20µA after some power-optimizations), but as soon as I write to the SPI using spi_transcieve(), the power consumption goes through the roof.

Tron

RE: nrf9160 SPI power consumption

Simon — Fri, 24 Jan 2020 10:25:27 GMT

What version of the nRF91 DK do you have? If you have v0.7.0, v0.8.2, v0.8.3 or v0.8.4, you should follow the approach explained in this ticket.

Have you remembered to cut SB44 (if you have v0.7.0, v0.8.2, v0.8.3 or v0.8.4)
Measure the current with an ammeter by connection to pins 1 and 2, where pin 3 is closest to the USB connector (if you have v0.7.0, v0.8.2, v0.8.3 or v0.8.4)

Best regards,

Simon

RE: nrf9160 SPI power consumption

Tron — Fri, 24 Jan 2020 09:38:25 GMT

I've done voltage measurements on the custom card, and it seems I have left some pins high on the spi interface. These pins supply other spi devices with voltage, and that draws current to those components through those pins.

Sorry for bothering you, as usual, the error is between chair and screen 🙂. Have a nice weekend.

RE: nrf9160 SPI power consumption

Tron — Thu, 23 Jan 2020 14:11:42 GMT

Measuring the described way, I see a current of around 1A

As far as I've uerstood, I need to use an external power as well. Which of the pins on the opposide side of the usb connector is +?

BTW, using usb as power-supply, did i burn the dk?

RE: nrf9160 SPI power consumption

Simon — Thu, 23 Jan 2020 13:31:46 GMT

[quote user="tronwa"]Is there an external flash on the DK?[/quote]

There is no external flash on the DK, only the 1MB flash integrated on the nRF9160 SiP.

[quote user="tronwa"]How would you recommend me to do current measurements? [/quote]

Check out Using a current meter for current measurement on the infocenter.

Best regards,

Simon

RE: nrf9160 SPI power consumption

Tron — Thu, 23 Jan 2020 13:26:42 GMT

AFAI see, the code doesn't run properly on the dk. At least, it doesn't report to my server.

RE: nrf9160 SPI power consumption

Tron — Thu, 23 Jan 2020 13:17:31 GMT

the devkit, there are 2 connectors, one marked nRF supply & current measurement, the other external supply.

How would you recommend me to do current measurements? My initial reflex is to use the external supply pins, and connect an ampmeter on one of the supply lines.

RE: nrf9160 SPI power consumption

Tron — Thu, 23 Jan 2020 12:19:55 GMT

aah, this explains a lot. Is there an external flash on the DK?

RE: nrf9160 SPI power consumption

Simon — Thu, 23 Jan 2020 12:02:45 GMT

Strange. I tested it with an nRF91 DK (I probably should have mentioned this), could you test the code on the DK as well? If the current consumption is high there as well, there is probably something wrong with the code. If not, I will test it on your custom hardware.

Best regards,

Simon

RE: nrf9160 SPI power consumption

Tron — Thu, 23 Jan 2020 11:52:07 GMT

I've done everything according to recommendations. I've tried programming the device directly with nrfjprog (or more precisely nrf91_jflash.exe), as well as through segger and nrfjprog. I have built using segger ide, as well as west. Still, no changes in current consumption. I'm trying with another card now 🙂.

RE: nrf9160 SPI power consumption

Simon — Tue, 21 Jan 2020 15:19:32 GMT

I tested your application on the developer branch along with NCS v1.1.0.

Try disabling the serial logging from mcuboot. It decreased the current consumption from 1.2mA to 85.8uA when I did it. It can be achieved by doing the following:

Add the following piece of code to your projects CMakeList.txt (nrftracker\CMakeLists.txt)

set(mcuboot_CONF_FILE
	prj.conf
    ${CMAKE_CURRENT_LIST_DIR}/mcuboot.conf
    )

Create the file nrftracker\mcuboot.conf with the following content:

CONFIG_SERIAL=n

run west build -b nrf9160_pca10090ns
Check if CONFIG_SERIAL is present in \nrftracker\build\mcuboot\zephyr\include\generated\autoconf.h
- If it is, then something went wrong
Run nrfjprog --eraseall
Run west flash
Reset your chip and measure the current

Best regards,

Simon

RE: nrf9160 SPI power consumption

Simon — Mon, 20 Jan 2020 15:27:54 GMT

I am not in the office right now and I'm not able to test this. I will measure it again tomorrow.

Best regards,

Simon

RE: nrf9160 SPI power consumption

Tron — Fri, 17 Jan 2020 09:55:35 GMT

I've tested, and still see 1.5mA. Please verify that you have checked out the develop branch, and that LIFO_ENABLED is defined.

RE: nrf9160 SPI power consumption

Tron — Fri, 17 Jan 2020 08:11:12 GMT

Check out the comment on line 55, is this fixed now?

Tron

RE: nrf9160 SPI power consumption

Simon — Thu, 16 Jan 2020 16:03:01 GMT

I have done some investigation and figured out what's causing the high current consumption, could you test it on your end as well?

In nrftracker/src/adc.c→adc_init(), comment out NRF_SAADC_NS->TASKS_CALIBRATEOFFSET = 1;

When I did this, the current consumption dropped from 1.5mA to 85uA.

Best regards,

Simon

RE: nrf9160 SPI power consumption

Tron — Wed, 15 Jan 2020 06:29:08 GMT

Please make sure you check out the develop branch.

RE: nrf9160 SPI power consumption

Simon — Mon, 13 Jan 2020 16:27:00 GMT

I have sent you an email and I will see if I can get hold of your hardware tomorrow.

Best regards,

Simon

RE: nrf9160 SPI power consumption

Tron — Mon, 13 Jan 2020 13:19:43 GMT

Hi there Simon

I suggest the following:

You have my email address, you send me an email, and I will invite you to my bitbucket git repo, and you will be able to clone it
then it's up to you to keep the ticket public or not.
Do you have access to our custom hardware? It's available in Trondheim, afaik. I can provide you with hardware in Oslo as well, or send it by surface mail if desired.

Wr,

Tron

RE: nrf9160 SPI power consumption

Simon — Mon, 13 Jan 2020 12:09:50 GMT

Could you upload your application (I can make the ticket private if you would like to)? Then I can perform some tests myself and figure out what may cause this.

Best regards,

Simon