nrf9160 SPI power consumption

[Tron]

Hi

On my custom board, I have an external flash connected via SPI. . The nrf runs on mfw 1.1.0. 

Without activating the flash, I get an average current consumption of around 45 µA. As soon as i do a spi_transcieve(...) call, the power consumtion jumps up till 1,4 mA, and will not go down again during sleep. This current corresponds exactly to what I see if serial communication is enabled. I don't know if this is relevant or not. 

The flash is powered down, and should in a ready state draw around 25µA.

Yours, 

Tron

[Simon]

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

[Tron]

Please make sure you check out the develop branch. 

[Simon]

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

[Tron]

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

Tron

[Tron]

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

[Simon]

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

[Simon]

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

[Tron]

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 . 

[Simon]

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

[Tron]

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

[Tron]

On 

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. 

[Tron]

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