BLE sleep advertising at fast rate of 1 or 2 ms

DS.4 · ‎2025-04-28

Got this issue on entering sleep.

I set my advertising to 1 second, and do not touch it after.

Before sleep, all was good, I was advertising every ~1 second

but when I enter sleep I notice it jumps to 1 or 2 ms.. very fast, and not so power consuming.

I didn't test with power testing tool, to validate the peaks, but only via the phone app.

Wonder what might be causing this?? Do I accidently shutdown some peripheral important for BLE?

FilipKremen · ‎2025-04-30

Hello,

can you please describe the issue more in detail? Can you show any waveform?

Also, if you could share the steps when you're testing it, so I could reproduce it on my side.

Thank you.

Best regards,

ST support

DS.4 · ‎2025-05-11

We are currently trying to get our hands on a better sniffing tool, but this might take some time..

Meanwhile, did manage to improve it slightly by following the free rtos example with ble.

BTW, I am on stack 21 .

Now, I see a drop from 1 sec ( initial pre sleep setting ) to around 200-250 ms during sleep.

Any idea to why do I get this drop? Any debug I can add to BLE stack? Anything you know of that might be causing this ?

I did follow the example as much as possible. HAL, RTC, CLOCKS.. ( FreeRTOS BleHeartRate)

We use a slightly different operating system, a CMSIS one.

Do you guys have a CMSIS RTOS sleep example?

FilipKremen · ‎2025-05-12

Hello,

which board do you use? Is it a custom board? You can enable debug traces in the app_conf.h file.

Can you please share the measurement? Thank you.

Unfortunately, there is no CMSIS RTOS sleep example in the WB package.

Best regards,

ST support

DS.4 · ‎2025-05-12

As soon as we hit EnterLowPower() , out advertising goes crazy ( 1- 2 ms )

This pretty sure is caused because we use PLL's in SystemClock_Config .

They are used also for our :ADC , RTC.

(Although that's not the config you guys use in your example)

After turning PLL off , no issue !

BUT WHY?

and is there any way we don't have to make grand changes in our clocks to fix this?

.