Apple

On 13 Jan 2015, at 00:42, Martijn The <email@hidden> wrote:

> I’m reasonably sure however looking at the iOS functions that you cannot have an iOS device be a peripheral and, when a central connects to it, use that connected central as a server, discover its characteristics, read and write to it.

Unfortunately, there is no "-centralDidConnect:" delegate method. So just letting the other device connect to the iOS device is not enough to get any delegate methods fired on your CBPeripheralManagerDelegate.

But... once you do get hold of a CBCentral object -- either through -peripheralManager:central:didSubscribeToCharacteristic: or via the CBATTRequest's `central` property that you get when receiving a read/write -- you can use the identifier of that CBCentral object and use it with CBCentralManager's -retrievePeripheralsWithIdentifiers: to get the CBPeripheral for the same device. Once you've got that you can do service discovery and read/write etc.

Agree it's extremely clumsy, but not impossible :)

Martijn

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On Sun, Jan 11, 2015 at 2:11 AM, Roland King <email@hidden> wrote:
On embedded hardware platforms it doesn’t actually matter which device is peripheral and which is central, once they’ve connected either or both can act as GATT server or client. On the Nordic platform I use for instance you can call GATT client and server functions whether you are running as central or peripheral.

I’m reasonably sure however looking at the iOS functions that you cannot have an iOS device be a peripheral and, when a central connects to it, use that connected central as a server, discover its characteristics, read and write to it. The only functions to perform that are on CBPeripheral and the only way to get a CBPeripheral is to be a CBCentralManager. If you are a peripheral, ie a CBPeripheralManager, you get the central (when it asks for something) but there’s no API on CBCentral which allows you to treat it as a GATT server, even though it is one.

Seems that iOS ties Central to Client and Peripheral to Server very tightly. Is this correct or is there a way to be CBPeripheralManager and still, when connected, be a GATT client of the connected central?

Regrettably in this particular instance the device the phone is connecting to has to be a central, so the phone needs to be a peripheral.