Current consumption on WDT Reload

[tossh]

Hi, I'm working on nRF52832 at SDK ver15.3.

My problem is Current consumption increasing (82uA -> 550uA) when WDT Reloading in sleep mode.

I set WDT configuration "Pause in SLEEP and HALT" mode from errata 88 and some issues.

But, not improving that.

However, I confirmed the wondering event.

I see only this current consumption increasing in release compiled hex file,

and I cannot see in debug compiled hex file.

Is there anyone who can understand this ?

Best Regards,

Tossh

[Kenneth]

Have you added a >125us delay after reloading WDT as described in the workaround before going to sleep: "Do not enter System ON IDLE within 125 µs after reloading the watchdog."

[tossh]

Dear Kenneth,

Thanks for your reply.

I'm sorry for late reaction, cuz the validation needed a time.

I try to add time delay before going to sleep mode.

Current composed 80uA. 

however, sometimes increase approx. 500uA.

Do you have other  plans ?

Best Regards, 

tossh

[Kenneth]

Are you sure it is related to WDT? Can it be floating GPIO's or other functionality that is drawing current? How did you implement time delay? nrf_delay_us(125) after wdt_reload()?

WDT should only draw ~0.1uA in sleep.

Kenneth

[tossh]

Dear Kenneth,

yes, I confirmed current did not increase when disabled WDT.

80uA is the base current of my circuit.

I added 125us delay like, 

NRF_WDT->RR[0] = WDT_RR_RR_Reload;

nrf_delay_us(125);

Is this code wrong?

Best Regards, 

tossh

[Kenneth]

The code looks good. What is the nRF52832 ic markings? Are you measuring on an nRF52-DK or your own hardware?

80uA seems like an odd current value to begin with, are you measuring average or looking at the actual current consumption using an power profiler kit? How often do you reload the WDT?

[tossh]

nRF52832 IC marking is QFAAE1 1852EF.

I measure current on own hardware, and average current by a tester. 

WDT reload time is per 500ms.

[Kenneth]

You need to measure this using a power profiler (e.g. https://www.nordicsemi.com/Software-and-tools/Development-Kits/Power-Profiler-Kit) Then we can find what is causing the current consumption (e.g. is it periodic, spikes etc).

Kenneth