Power/current consumption

[Tron]

I have 2 questions, both related to power/current consumption. 

My setup is a custom board, with mfw 1.1.0. I havev arlier seen current consumptions in the µA-range. I now have turned off logging in the SPM (CONFIG_SERIAL=n) in nrf/samples/nrf9160/spm/prj.conf, but still experience that the device draws between 5 and 6 mA during sleep. 

my prj.conf file for the project looks like this: 

#Items to change when minimizing current consumption
CONFIG_LOG=n
CONFIG_SERIAL=n
CONFIG_UART_CONSOLE=n

1. What else do I need to configure during compilation to get back in the µA-range for the device?
2. IS there a way to configure the system, not having me edit files outside my project folder. I have a spm.conf file in my project, might that be a solution?

Thank you in advance, 

Tron

[Sigurd]

Hi,

the device draws between 5 and 6 mA during sleep. 

 Do you have a plot of the current consumption ? Is it a constant 5-6 mA baseline draw, or do you have higher peaks(range 40-50mA)(but the average is 5-6mA) ?

If it's a constant 5-6 mA, then it could be that the CPU is busy-looping/spinning somewhere, and not going to sleep.

If you have 40-50 mA peaks at a regular interval, it could be that the modem is sending or receiving data.

BR,

Sigurd

[Tron]

Hi

The current consumption doesn't peak. It is a (more or less) constant draw. It is basically the same application that drew currents in the µA range before the change to v1.1.0. I had to create a new directory when checking out the new version of the Nordic Connect SDK.

Yours, 

Tron 

[Sigurd]

Does the application work as intended after updating to v1.1.0 ?

If you are using SES(Segger embedded studio), you can try to run the code in a debug-session. Let the code run, and then click pause/break, and check if the CPU is busy-looping somewhere. You might need to do it a couple of times. If the CPU is sleeping, you should see in the disassembly on the right side in the IDE, that WFE/SEV is executed.

[Tron]

Hi again, 

The software behaves excellently. 

Running the device in debug mode seems to draw a lot more current.

Stopping the debugger on a random point in time, the breakpoint line is always on line 78 in cpu_idle.S, in the function z_arch_cpu_idle. This operation has been done 15 times, and no exceptions. 

WFE/SEV?

[Tron]

I found the guilty part, it was the external flash that was not turned off. Sorry for the inconvenience.