Current consumption

[kb2423]

Hi, 

I tried to monitor current consumption of my device. I used

 

sd_app_evt_wait();

and then used 

 // Wait for an event.
        __WFE();
        // Clear the internal event register.
        __SEV();
        __WFE();

I saw something like this

There are spikes on everywhere.

If I comment out sd_app_evt_wait(); or last __WFE(); it beacomes like that

I am using sdk 15.0.0, before this I was using sdk 14.2 and in 14.2 I was using sd_app_evt_wait function and there was no spikes. How can I fix it?

Thanks.

[kb2423]

I did some measurements with sdk 14.2, and result are same. 

Here is with sd_app_evt_wait() function

and this one has no sd_app_evt_wait() function

I did same thing for blinky examples in sdk 14.2 and 15.0, and there were no spikes with sd_app_evt_wait() function and without sd_app_evt_wait() function. So I assume those spikes don't appear because of me. Thank you for your replies.

[Simonr]

Hi

There are a few changes between the SDKs, so there's just a matter of finding what change is causing these spikes when combined with your project. Could you please upload the SDK15.0 version of your project with instructions on how to recreate this, so I can have a closer look? I can set the case to private if you don't want to share your project with the rest of the community. This way the case will be treated with confidentiality, and only Nordic engineers will be able to see the case. Just say the word!

Best regards,

Simon

[kb2423]

There are misunderstandings because of my wording. Last four pictures are not from my project. They are from SDK 15.0's and 14.2's base example(ble_app_hrs_rscs_relay). If I comment out sd_app_wait() function in base example there are no spikes, if I don't do any changes spikes appear. Then I tried this in ble_app_blinky example without any changes(code still calls sd_app_wait() function) and there were no spikes(I didn't put here any pictures for it). 

So I saw that if I download the untouched version of SDK 15.0 or SDK 14.2 , then run projects ble_app_hrs_rscs_relay and ble_app_blinky without any changes. Relay example has spikes and blinky example hasn't. My old project was built on blinky example and new example is built on relay example, that's why I started to see those spikes. Can you check those examples? If you say those spikes are unexpected then I can take your advice to fix it, if those are expected then it's okay for me too. Thank you.

[Simonr]

Hi

I've tested the ble_app_hrs_rscs_relay example and measured the current using the PPK and the Power Profiler application in nRFConnect for desktop. All tests were made with the same nRF52832 DK and the same PPK. Here are my results:

ble_app_hrs_rscs_relay SDK v15.0.0

As you can see, there are no unexpected spikes here.

ble_app_hrs_rscs_relay SDK v14.2.0

No unexpected spikes here.

ble_app_hrs_rscs_relay SDK v15.2.0

All three are very similar, with no unexpected spikes.

Could you please specify which unmodified example you are seeing these spikes in? I would like you to delete your SDK v15.0 and try downloading a "fresh" one from our Infocenter. Please see if you still experience these unexpected current spikes.

Best regards,

Simon

[kb2423]

Thank you so much for your effort.

When you comment out idle_state_handle function in those examples, lines in your pictures will become more stable. As I said before I was working on ble_app_blinky example before, and there ware no spikes with or without power management functions.

This pictures from fresh SDK v15.0.0

for ble_app_hrs_rscs_relay

with  idle_state_handle function, 

without  idle_state_handle function.

for ble_app_blinky

with  idle_state_handle function, 

without  idle_state_handle function.

As you see there is no change in ble_app_blinky but there are changes in ble_app_hrs_rscs_relay example that's why I thought those spikes are unexpected.  Thank you.