CPU2 on STM32WB55 seems to wake every 2 seconds even without a connection or advertising.

[BStic.2]

I've been doing some current draw analysis of our product and I am trying to get the best idle current that I can get. We have a mode where there is no BLE connection and no advertising. Essentially no BLE communication at all. In this mode I would like to stay in STOP2 mode for as long as possible. I am using the STM32 Power monitor to observe the current draw behavior and I am seeing what looks like CPU2 waking from sleep every 2 seconds, even though there is no connection and no advertising. Is there a way to stop this? I am using v1.13.3 of the BLE stack.

[Remy ISSALYS]

Hello,

I think you are in low power advertising mode, can you check the shape of consumption peak ? And can you try to perform your test with BLE_HeartRate by removing all the call to Adv_Request to see if you have the same result ?

In order to stop the advertising, you should call aci_gap_set_non_discoverable function.

Best Regards

[BStic.2]

I have verified that we are sleeping every 8 seconds and I have disabled all advertising and I still get the 2 second pulse.

[Remy ISSALYS]

Hello,

Are you using the nucleo board ?

Best Regards

[BStic.2]

No, we are using a custom board. FYI, It looks like the spike is coming from CPU1. When I halt CPU1 with the debugger, I can see it stop - So I guess this is in my code somewhere.

Thanks.