Wakeup procedure via BLE for system in low power mode

[SDi B.2]

Hi,

I am currently working on a bluetooth application developing it on Nucleo STM32WB55 (FW version V1.13.1, BLE Stack Full).

If the system is in a low power state, STOP2, can it be woken up via bluetooth?

If so, is this awakening established by any kind of bluetooth activity that wakes up CPU2 and then the whole system?

Is it possible to reach the STOP2 mode also once the connection with an external device has been made, so that it is woken up by a message, or it happens only during advertising in the interval between two requests, waking up the device by making the connection?

Thank you very much

[Remy ISSALYS]

Hello,

According to reference manual RM0434 (p151), see low power wakeup sources as below:

Of course, it's possible to reach STOP2 mode once the connection is established. When you have a BLE connection up and CPU1 enters Stop2, the system will enter Stop2 between connection interval and will be in RUN mode during radio event. You shall not do anything to control the CPU2 low power mode. The wireless stack running on CPU2 makes sure the lowest low power mode on CPU2 is requested depending on the use case. Basically, you should develop you application on CPU1 in the same way as if it was a single core product (i.e you dont need to care about CPU2 for low power management).

Best Regards