Reconnecting to nRF via BLE failes the first time with the nRF Connect App

[Tobias Kaupat]

I have the following problem in my app:

• Connect with BLE
• Using the device works
• Disconnect
• Connect to BLE Device
• Start Gatt.DiscoverServices()
• Android does a Disconnect (Credentials should be reused)

Whith the nordic android app I have the following behavior after beeing in the state where my app can not connect anymore:

• Connect to BLE Device
• DiscoverServices seems to start
• Android does a Disconnect
• Connect to BLE Device (again)
• Connection is established and can also be established again with my app

This tells me that there seems to be some magic, that the nordic App does (e.g. in de Disconnect event) that "repairs" the android system to allow a reconnect to a already bonded device.

Can you give me any hints or maybe code that shows what is happening during the disconnect, or do you have any idea what could be wrong with my app?

Thanks, Tobias

[Tobias Kaupat]

Btw I found your android lib and it seems to answer my questions: https://github.com/NordicSemiconductor/Android-BLE-Library

[Hung Bui]

Hi Tobias, 

I'm not sure why in your case the connection can't be re-established. Which side erases the bond information ? Do you store bond information in your app ? 

There is an option to erase bond on the phone from the app (you can find this option in nRF Connect app. I assume you don't do that in your app. 

[Tobias Kaupat]

We keep the Bond information on android side.

[Hung Bui]

Yes, but bond information should be stored on both side. Othewise they can't reestablish the connection.