"floor" current of 2.9 mA with code migrated to SDK15 (from SDK12)

[ThierryC]

I have an existing Firmware (build on Crossworks) that has correct "floor" power consumption (< 10 uA during sd_app_evt_wait() on my setup).

I migrate my code to rune with SDK15 (mainly changed SoftDevice API) and after that, I have a constant current consumption of about 2.9 mA !

Note that after SYSTEMOFF, I can correctly be < 1 uA.

So apparently I missed something during my porting and it seems that a resource is constantly alive. But I cannot figure out what it is.

Any hint to debug such issues ? Any register to check and see which resources are activated ?

Any suggestion or link to similar issue is welcome to help me to progress on this issue.

[Kenneth]

In general you may check out:
https://devzone.nordicsemi.com/b/blog/posts/optimizing-power-on-nrf52-designs

You may also take a look at the nrf_pwr_mgmt_run() implementation from the nRF SDK.

[ThierryC]

Hmm, investigating more deeply, it seems more to be around RTC.
I found this link and it seems to be exactly the use case I encounter (3 mA consumption after I get access to RTC->COUNTER) : https://devzone.nordicsemi.com/f/nordic-q-a/40102/app_timer_cnt_get-causing-high-power-consumption/156812#156812
So I try now the suggested fix... but difficult to setup on my Crossworks environment.Let see if it solve the issue after...

[ThierryC]

OK, I found the problem: I was correctly using the nrf_power_mgmt_run(), but I forgot to define NRF_PWR_MGMT_CONFIG_FPU_SUPPORT_ENABLED !

So problem is solved ! Thanks for your hints.

And for the story, what I still don't understand, is why I didn't saw this problem on SDK12 using sd_app_evt_wait() ? If someone has an explanation.