iOS 6 - Bluetooth LE disconnect

ios6 core-bluetooth disconnect bluetooth-lowenergy
ChrisB picture ChrisB · Oct 18, 2012 · Viewed 7.6k times · Source

Ok what the heck is up with iOS6 and how it handles Bluetooth LE disconnections? Before the device would disconnect immediately but now, for some strange reason, the device waits to disconnect for about 30-60 seconds. I need it to disconnect ASAFP!

I've been searing all over the internet trying to figure out how to initiate an immediate disconnection from the peripheral and I found this nifty email that explains a workaround is to unsubscribe from notifications on the service characteristics.

Now I think I'm doing that.. When I want to disconnect I call [connected_device setNotifyValue:NO forCharacteristic:connected_characteristic]

Then, in the didUpdateNotificationStateForCharacteristic function, I have...

if((int)characteristic.isNotifying == 0){
   [manager cancelPeripheralConnection:peripheral];
}

In the function didDisconnectPeripheral...

connected_peripheral = nil;
connected_characteristic = nil;
[connected_peripheral release];
[connected_characteristic release];

I've also taken a good hard look at Apple's CoreBluetooth Temperature Sensor example but it hasn't really helped much....

Any help on this would be amazing!! I just don't know what I'm missing.....

UPDATE: It looks like the app needs to be connected to the bluetooth device for at least a minute before it is allowed to disconnect. If the app is connected for over a minute it will disconnect immediately when the command is sent. Otherwise, it will wait until that one minute mark to actually disconnect.

UPDATE: When I try to disconnect before the one minute mark, I get the following output to the log when the device actually disconnects.

Oct 24 16:49:35 Christophers-iPhone awdd[8168] <Error>: libMobileGestalt copySystemVersionDictionaryValue: Could not lookup ReleaseType from system version dictionary
Oct 24 16:49:35 Christophers-iPhone awdd[8168] <Error>: CoreLocation: CLClient is deprecated. Will be obsolete soon.

Answer

Anders Grunnet-Jepsen picture Anders Grunnet-Jepsen · Oct 25, 2012

According to Apple, this new feature is "by design". The way we resolved this issue was to send a command to the Peripheral and have it disconnect from its end. If you do this, then the disconnect is immediate. I do not know why Apple changed this behavior from iOS5 to iOS6 but they must have had their reasons. Of course this solution only works if you have access to the Peripheral firmware and can change it. If there is a different solution, then we have not found it.

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