STM32WL and STM32WB in the same project

[dovoto]

I am working on a battery operated design which utilizes the WB as the main logic CPU with a WL to connect to LoRa networks.   This device is very small, putting the antennas uncomfortably close together.  To avoid certification issues wed like to ensure we do not transmit on both devices at the same time.  

Have there been any issues with certification reported when using both chips simultaneously? 

We think, due to LoRa stack timing requirements, the easiest solution will be to pause BLE while transmitting on LoRa but there does not seem to be any convenient hook for pausing BLE communications in the SDK without completely shutting down and restarting.

Any general advice would be appreciated.

[STTwo-32]

Hello @dovoto 

Happy to see this your use case. we have already a Multi connectivity solution for asset tracking that include both LoRa using an STM32WL and BLE using the STM32WB it is the STEVAL-ASTRA1B - Multiconnectivity asset tracking reference design based on STM32WB5MMG and STM32WL55JC - STMicroelectronics. For your Use case, I suggest you contact one of our FAEs so they can provide you with the necessary information depending on the certifications you are locking to have, your Design,..

Best Regards.

STTwo-32

[dovoto]

The BLE antenna on this design is grounded and not in use...it is unclear to me why the WB chip is even on this design given the WL board should have been able to handle the business logic. 

My concern is specifically if both radios are active in close proximity and if this will cause regulatory headaches and if so are there adequate means in the ble stack to deconflict.

[dovoto]

A bit more research tells me this is a solved problem via PTA (packet transfer arbitration) and that my current WBA chip does not support it but that there is one that will.  

[STTwo-32]

Hello @dovoto 

PTA (packet transfer arbitration) is not supported for the STM32WBA since it includes only one antenna for communication (the 2.4 GHz one). So, no need to implement such a one. You may can thing about setting such a configuration using a HW solution (switcher for example).

Best Regards.

STTwo-32