Apple

On 25 Jul 2013, at 15:50, Raj Sathianarayanan <email@hidden> wrote:

Just one more quick observation. After disconnecting if I use my cached peripheral to issue the new connect call instead of calling retrievePeripherals it seems to work.
Anyone know if this will cause other problems?

On Wed, Jul 24, 2013 at 5:32 PM, Raj Sathianarayanan <email@hidden> wrote:

Thanks for taking the time to reply! No I haven't sniffed the traffic to see what is going on but I just ordered the "CC2540 Bluetooth low energy USB Dongle" and will report back after I have investigated some more.

Raj

On Wed, Jul 24, 2013 at 3:34 PM, John Earl <email@hidden> wrote:

Could be any number of things - especially if your peripheral is also under active development. Have you sniffed the traffic to see what is going on? It can take several tries to do this with the TI sniffer, but it can yield much more conclusive information about the cause of the failure.

Also my experience has been that this behavior varies with iOS version, even with minor version updates. Are you on 6.1.3 (we have had much better luck with connectivity on 6.1.x than 6.0.x, for example)?

Examples of things that can cause this behavior, where you don't even get to service discovery;

* peripheral requests channel parameters that iOS really doesn't like

* peripheral power level too low (misconfiguration?)

John

On 24 Jul 2013, at 18:46, Raj Sathianarayanan <email@hidden> wrote:

Hi All,

I have run into a problem where establishing a connection to my device while my app is running in the background is very inconsistent. I have a device that will send over some data (after the user selects to do so) after which it will disconnect. After reading through the mailing list archives and stackoverflow I went with

1. Saving the UUID of the device after establishing a connection once using a scan
2. After that, Once a disconnect happens (or the app is launched) I call retrievePeripherals with that UUID and try to make a connect call

When the app is in the background it sometimes ends up in an endless connect/disconnect loop until the device times out.
I have added logging to all the delegate methods and the output is as follows (I have also attached some sample code after)

Bad Attempt:
2013-07-24 11:59:29.759 AppName[23779:907] Peripheral connected: DeviceName
2013-07-24 11:59:30.125 AppName[23779:907] Peripheral disconnected: DeviceName
2013-07-24 11:59:30.129 AppName[23779:907] Attempting to connect to saved device UUID: 038B1260-2650-CB7B-6C4A-BB20DF6CEA0D
2013-07-24 11:59:30.131 AppName[23779:907] Retrieved peripheral: 1 - (
"<CBConcretePeripheral: 0x210aa950 UUID = <CFUUID 0x253931c0> 038B1260-2650-CB7B-6C4A-BB20DF6CEA0D, Name = \"DeviceName\", IsConnected = NO>"
)
2013-07-24 11:59:31.129 AppName[23779:907] Peripheral connected: DeviceName
2013-07-24 11:59:31.898 AppName[23779:907] Peripheral disconnected: DeviceName
2013-07-24 11:59:31.900 AppName[23779:907] Attempting to connect to saved device UUID: 038B1260-2650-CB7B-6C4A-BB20DF6CEA0D
2013-07-24 11:59:31.903 AppName[23779:907] Retrieved peripheral: 1 - (
"<CBConcretePeripheral: 0x210aa950 UUID = <CFUUID 0x253931c0> 038B1260-2650-CB7B-6C4A-BB20DF6CEA0D, Name = \"DeviceName\", IsConnected = NO>"
)
This loops till the device times out.

Successful Attempt:

2013-07-24 12:36:29.175 AppName[23883:907] Attempting to connect to saved device UUID: 038B1260-2650-CB7B-6C4A-BB20DF6CEA0D
2013-07-24 12:36:29.246 AppName[23883:907] Peripheral connected: DeviceName
2013-07-24 12:36:29.252 AppName[23883:907] Retrieved peripheral: 1 - (
"<CBConcretePeripheral: 0x1ed36740 UUID = <CFUUID 0x1ed859d0> 038B1260-2650-CB7B-6C4A-BB20DF6CEA0D, Name = \"DeviceName\", IsConnected = YES>"
)
2013-07-24 12:36:29.413 AppName[23883:907] Peripheral disconnected: DeviceName
2013-07-24 12:36:29.417 AppName[23883:907] Attempting to connect to saved device UUID: 038B1260-2650-CB7B-6C4A-BB20DF6CEA0D
2013-07-24 12:36:29.421 AppName[23883:907] Retrieved peripheral: 1 - (
"<CBConcretePeripheral: 0x1f8295b0 UUID = <CFUUID 0x1f852740> 038B1260-2650-CB7B-6C4A-BB20DF6CEA0D, Name = \"DeviceName\", IsConnected = NO>"
)
2013-07-24 12:37:22.486 AppName[23883:907] Peripheral connected: DeviceName
2013-07-24 12:37:23.362 AppName[23883:907] Service found with UUID: Unknown (<aec465ca 9c7d4e7f bf00ec05 4692a1da>)
2013-07-24 12:37:23.811 AppName[23883:907] Notification characteristic discovered for DeviceName
2013-07-24 12:37:24.373 AppName[23883:907] Received new packet...

Code Snippet

- (void)centralManager:(CBCentralManager *)central didRetrievePeripherals:(NSArray *)peripherals
{
#ifdef BLUETOOTH_DEVICE_LOGGING
NSLog(@"Retrieved peripheral: %u - %@", [peripherals count], peripherals);
#endif

CBPeripheral* peripheral = [peripherals objectAtIndex:0];
if ([peripheral isConnected])
return;

if (![_retrievedPeripheral isEqual: peripheral])
{
[self clearAndReleaseRetrievedPeripheral];
_retrievedPeripheral = peripheral;
[_retrievedPeripheral retain];
}
else
{
#ifdef BLUETOOTH_DEVICE_LOGGING
NSLog(@"Retrieved peripheral is the same as the one passed in to didRetrievePeripherals")
#endif
}

[[self bluetoothCentralManager] connectPeripheral: peripheral options: nil];
}

- (void) onDisconnectPeripheral: (CBPeripheral *)aPeripheral error:(NSError *)error
{
#ifdef BLUETOOTH_DEVICE_LOGGING
NSLog(@"Peripheral disconnected: %@", aPeripheral.name);
#endif

[self clearAndReleasePeripheral];
[self connectToSavedDevices];
}

- (void) connectToSavedDevices
{
NSString* deviceUUID = [self getBluetoothDeviceConnectionUUID];
if (deviceUUID != nil)
{
#ifdef BLUETOOTH_DEVICE_LOGGING
NSLog(@"Attempting to connect to saved device UUID: %@", deviceUUID);
#endif
CFUUIDRef uuid = CFUUIDCreateFromString(NULL, (CFStringRef)deviceUUID);
if (uuid)
{
[[self bluetoothCentralManager] retrievePeripherals:[NSArray arrayWithObject:(id)uuid]];
CFRelease(uuid);
}
}
}

Any thoughts on what I might be doing wrong?

Thanks
Raj

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