Bonded peripheral is disconnected after few minutes

RE: Bonded peripheral is disconnected after few minutes

Einar Thorsrud — Wed, 02 May 2018 12:36:02 GMT

There is no indication on what caused the disconnect in the log. From the nRF side there was a timeout, though. One theory is that perhaps the phone has a lower clock accuracy than reported. In that case, the transmit/receive window might not overlap at some point. You could probably test that by configuring a lower clock accuracy on the nRF52832 side (assuming you use a crystal, you could set NRF_SDH_CLOCK_LF_ACCURACY to 500 ppm). This would increase the margin. If not, there is probably something else happening within the phone, but it is difficult to say exactly what.

RE: Bonded peripheral is disconnected after few minutes

Gilpa — Mon, 30 Apr 2018 13:34:35 GMT

As requested, here is the log from NrfConnect :

nRF Connect, 2018-04-30
Nordic_Template (C3:79:D8:30:9F:AC)
V 14:25:00.470 Connecting to C3:79:D8:30:9F:AC...
D 14:25:00.470 gatt = device.connectGatt(autoConnect = false)
D 14:25:01.307 [Callback] Connection state changed with status: 0 and new state: CONNECTED (2)
I 14:25:01.307 Connected to C3:79:D8:30:9F:AC
D 14:25:01.308 [Broadcast] Action received: android.bluetooth.device.action.ACL_CONNECTED
D 14:25:01.313 wait(1600ms)
V 14:25:02.914 Discovering services...
D 14:25:02.914 gatt.discoverServices()
D 14:25:02.962 [Callback] Services discovered with status: 0
I 14:25:02.962 Services discovered
V 14:25:02.976 Generic Access (0x1800)
- Device Name [R W] (0x2A00)
- Appearance [R] (0x2A01)
- Peripheral Preferred Connection Parameters [R] (0x2A04)
- Central Address Resolution [R] (0x2AA6)
Generic Attribute (0x1801)
- Service Changed [I] (0x2A05)
Client Characteristic Configuration (0x2902)
D 14:25:02.977 gatt.setCharacteristicNotification(00002a05-0000-1000-8000-00805f9b34fb, true)
D 14:33:45.669 [Broadcast] Action received: android.bluetooth.device.action.ACL_DISCONNECTED
I 14:33:45.670 Disconnected
D 14:33:45.683 [Callback] Connection state changed with status: 0 and new state: DISCONNECTED (0)
D 14:33:45.685 gatt.refresh() (hidden)

Hope that will help

RE: Bonded peripheral is disconnected after few minutes

Einar Thorsrud — Mon, 30 Apr 2018 12:00:35 GMT

Sounds like there is a problem on the phone side, then. Have you checked the log from the nRF Connect app (You can get the log by swiping to the right)? Any clues there?

RE: Bonded peripheral is disconnected after few minutes

Gilpa — Mon, 30 Apr 2018 11:50:07 GMT

Hi Einar,

The sniffer trace doesn't show anything very relevant... Empty PDUs are exchanged between the slave and the master (normal because I do nothing else other than being connected). When the disconnect occurs, no more empty PDUs and the slave simply advertise again.

I've tested with another phone this morning (Samsung S6 with Android 7.0) and everything works as expected (no disconnection).

With the Wiko I can also reproduce the bug with the ble_app_hrs example from the SDK 15.

RE: Bonded peripheral is disconnected after few minutes

Einar Thorsrud — Mon, 30 Apr 2018 10:47:09 GMT

Hi Paul,

Do you have a sniffer trace of the communication between the phone and the nRF? Does it only happen with the Wiko Rainbow, or does it also happen with other centrals?