High power consumption with Distance Measurement enabled (when not active)

[xorly]

Hi,

We are experimenting with Distance Measurement feature a we observed 2 issues.

HW: Custom HW with: CR2032 coin cell -> joulescope -> 40 uF capacity in ceramic caps -> BL652 (nrf52832) module from Ezurio.

SW: NRF connect SDK 2.7.0, custom toolchain (gcc 14.1). Simple app is using extended advertising and distance measurement is enabled.

• DCDC enabled
• CONFIG_PM=y
• CONFIG_PM_DEVICE=y
• CONFIG_DM_MODULE=y
• CONFIG_DM_RANGING_OFFSET_US=10000
• CONFIG_DM_INITIATOR_DELAY_US=1000
• only GPIOs enabled

Higher power consumption During advertising than online profiler expects

Screenshot from joulescope, average power consumption is around 92 uA (top right corner). No DM activity here.

Increased power consumption after distance measurement

When we make power on reflector and several distance measurement are made, power consumption never returns to original value.

To me, it looks like MPSL is started with first DM and then keeps waking MCU even though there is no need for more scheduling.

Green - advertising before DM

Blue - advertising + DM

Purple - advertising after DM

Details of advertising before and after DM (ignore slightly different time scale)

[xorly]

One more screenshot of advertising. It takes longer than online profiler displays. There are quite long pauses in between. Only 2 Bytes of AD data i sent. 9 more Bytes are in scan response (not being scanned in captured moment).

[xorly]

Ok, first issue is mostly resolved. I did not notice, my advertising running with 100 ms period and expected 500 ms. Despite that, power consumption timing does not match the profiler, but it's not a big deal.

[xorly]

One more update - those periodic power spikes in between advertising packets start appearing, once the device is scanned. It is not bound to DM.

[Simonr]

Hi

What issue is it that is still remaining now? Is it the increased power consumption after advertising? If so, what exactly is the average current consumption after advertisements, and can you zoom in on the graph so we can get a better view of how the spikes look? Something must not be going to sleep as expected if that's the case.

Best regards,

Simon

[xorly]

Hi, sorry for the mess, but I did not find a way how to edit original post to clean it up and remove outdated stuff from there.

One minor thing: Timing of the current waveform in RE: High power consumption with Distance Measurement enabled (when not active) does not match the timing from online power profiler.

Main issue are those periodic current spikes in between advertising packets. They seem to start after being scanned for the first time and they never stop.

OK: Start and periodic advertising (no excessive current spikes)

OK: Zoom 1 (multiple advertising packets)

OK: Zoom 2 (one advertising packet)

NOK: Transition before and after being scanned

NOK: Zoom 1 (detail of transition)

NOK: Zoom 2 (detail of one advertising packet + scan req. scan response and first 2 periodic current spikes)