any way to delete Central Address Resolution characteristic

[nimalhuang]

Hi, Guys,

I am using nrf52832 for our product. Recently I updated stack and sdk from s132v2/sdk12.1 to s132v4/sdk13. However, I see a new characteristic under Generic Acess 0x1800 primary service: "Central Address Resolution", UUID 0x2AA6. As a consequence, the connection handle value for CCCD and our own service including dfu service have been changed.

My current mobile app is not able to write the cccd and access other service due to handle value change. So I was wondering if there is any way I can disable or get rid of this new characteristic(Central Address Resolution) in the stack to make backward compatible?

I look at the Bluetooth core specification 5, it says for LE peripheral "Central Address Resolution is optional if Link Layer Privacy is supported, otherwise excluded", and for LE central "Central Address Resolution is mandatory if Link Layer Privacy is supported, otherwise excluded ". And our application use both BLE central and periphral roles.

Thanks

[Vidar Berg]

Hi,

Unfortunately, this is a known issue, and it is not possible to disable this characteristic in s132 v4. A workaround is to manually clear the attribute cache on the phone once DFU of app is complete:

• Cache refresh is possible via API in android apps, and we have that option in nrfconnect
• On ios you must toggle bluetooth enable to clear the cache.

I've put in a feature request for making this characteristic optional, but I'm afraid it's too late for a 4.x.x release if it gets implemented. I'm sorry for the inconvenience.

[nimalhuang]

Thanks for you answer vidar, let me see what I can do in the app.

[apuret]

Anything new about the optional Central Address Resolution characteristic ?

Is there implemented in SDK15/s132_5.1.0?

[Vidar Berg]

It's implemented in all softdevices starting from v.4.0.0, and is not optional unfortunately. Are you doing DFU from an older softdevice and seeing the same problem as described by OP?