nRF9160 dk in sleep mode

[Ubaid]

Hello All,

I am measuring the nRF9160 current in the sleep mode(program with just k_cpu_idle(); command) but still I am getting 530uA current. I have also tried to change the configuration files of SPM and board conf files as there was possibility of some resources that could draw power without my notice. Please, suggest me that what could be the possible solution.Thank you

Kit: nRF9160 dk v0.8.5

[Ubaid]

my src code is 

#include <zephyr.h>

void main(void)
{	
       k_cpu_idle();	

}

and proj.conf

CONFIG_TRUSTED_EXECUTION_NONSECURE=y

[Håkon Alseth]

Hi,

 

You'll need to disable UART in both your application and in SPM, to ensure that the peripheral clock tree does not run while you're in sleep.

To set the SPM configuration from your project, you can set a .conf specifically for SPM, like done in the lte_ble_gateway CMakeLists:

https://github.com/NordicPlayground/fw-nrfconnect-nrf/blob/master/samples/nrf9160/lte_ble_gateway/CMakeLists.txt#L15

 

In the above case, its named "child_secure_partition_manager.conf", and it should hold:

CONFIG_SERIAL=n

 

And your non-secure application's prj.conf should also hold the same config to disable serial.

 

Kind regards,

Håkon

[Ubaid]

Hi,

First of all, thank you Hakon for the help. Now, I am able to reduce the current consumption to 66uA by using the method you described in your last responce. But still, it is alot more than which is described in documentation. For reference snapshot of document is 

1. So, is there any way to reach to 1.4uA during the sleep mode?

2. secondly, I am using UART in my application and I need it to activate/deactivate it within my program(only when reading is required from UART) and remain deactivated in sleep modes? 

Best Regards,

Ubaid

[Håkon Alseth]

Hi,

 

Ubaid said:

1. So, is there any way to reach to 1.4uA during the sleep mode?

You have enter SYSTEMOFF mode (with no RAM retention) to get this value. Note that the RTC and LFCLK cannot run in this power mode, and you can only wake up on pin. On wakeup, the device will run from reset.

 

Ubaid said:

2. secondly, I am using UART in my application and I need it to activate/deactivate it within my program(only when reading is required from UART) and remain deactivated in sleep modes? 

 If you need UART to run in sleep mode, then you will have a penalty of approx. 500 uA in sleep. Do you only need the TX part? If so, you can turn off the RXD, like this:

https://github.com/Rallare/fw-nrfconnect-nrf/blob/nrf9160_samples/samples/nrf9160/udp_gps/src/main.c#L214

 

Ubaid said:

Now, I am able to reduce the current consumption to 66uA

What I did was to take the hello_world, add "CONFIG_SERIAL=n", then configure that with board "nrf9160_pca10090" (ie: secure region), then measure the current consumption (< 5 uA on my DK):

int main(void)
{
    //printk("Hello World! %s\n", CONFIG_BOARD);
    while(1) k_cpu_idle();
}

Then I added the spm.conf, which has "CONFIG_SERIAL=n", edited the CMakeLists.txt to have "spm_CONF_FILE" set, then configure the project with board "nrf9160_pca10090ns", and measured the same current consumption (< 5 uA).

Kind regards,

Håkon