nrf9160 idle current consumption ~500μA

[Niovi.sass]

Hi,

I have nRF9160 DK:

• PCA10090 v0.8.3 
• modem firmware 1.2.3

The specifications says that the minimum consumption current is 7µA. So I flash a hex file  which shuts down the modem and puts the chip to system OFF mode which I find it here and I measure consumption with STM32 Nucleo expansion board and it was ~500μA.

Also, I tried a very simple program

main.c

#include <zephyr.h>

void main()
{
	k_cpu_idle();

}

 prj.conf

CONFIG_SERIAL=n
CONFIG_AT_HOST_LIBRARY=n
CONFIG_STDOUT_CONSOLE=n
CONFIG_LOG=n

and

spm.conf

 

CONFIG_IS_SPM=y
CONFIG_FW_INFO=y
CONFIG_GPIO=n
CONFIG_SERIAL=n

nrf9160dk_nrf9160.overlay , nrf9160dk_nrf9160ns.overlay

&adc{
	status ="disabled";
};

&i2c1{
	status ="disabled";
};

&uart1{
	status ="disabled";
};

&i2c2{
	status ="disabled";
};

&uart2{
	status ="disabled";
};

&spi1{
	status ="disabled";
};

&spi2{
	status ="disabled";
};

&spi3{
	status ="disabled";
};

&uart0{
	status ="disabled";
};

but still current was ~500μA.

I tested older modem firmware as 1.1.0,1.1.1 and 1.2.0 also current ~500μA.

any suggestions?

Thanks in advanced,

Niovi.   

[Simon]

Can you upload the files <sample>/build/zephyr/.config and <sample>/build/spm/zephyr/.config, then we can see what Kconfigs are actually being set. It would be interesting to see if CONFIG_SERIAL=y is set in any of them. If you have more child images, can you check the .config of them as well (e.g. <sample>/build/mcuboot/zephyr/.config)?

If the .config's looks fine, would you be able to zip your application and send it over? Then I'll test it on my nRF91 DK.

Best regards,

Simon

[nexus]

Thanks for this hint, it helped me a lot to drill down the power issue I was seeing. I also measured about 520 uA for the blinky example until I realized the CONFIG_SERIAL flag needs to also be disabled in the spm module.

I have written up a tiny howto over here explaining how to replicate the issue and solve it:
High Idle Power Consumption on the NRF9160 DK using Blinky on Zephyr (~ 520 uA)

For configuring spm I found the following menuconfig command helpful:

west build -b nrf9160dk_nrf9160_ns -t spm_menuconfig

[Simon]

Thanks for sharing your solution! Another way of going about this is to add CONFIG_SERIAL=n to the file <application>/child_image/spm_prj.conf like done in <..>/asset_tracker_v2/child_image/spm/prj.conf.

[nexus]

Hey Simon

Thanks for pointing this out. This makes much more sense. I am realizing this is also the case in the UDP example of the nrf91. I will update my post accordingly. Thanks again!