Transmitting data with CoreBluetooth

Question

I'm developing an iOS app with an accompanying Bluetooth LE peripheral. The one step I don't seem to be able to solve is how to actually transmit the data from my app to the peripheral or vice versa.

What I've built so far is a test app that can connect to my sample Bluetooth peripheral, and read all of its services/characteristics/descriptors. It can toggle notifications for a given characteristic, and write to given characteristics. It is just this last step of "transmit n bytes to the peripheral, and receive m bytes from the peripheral" that I can't seem to figure out.

Looking at the External Accessory Framework (what I would use if Apple would actually give me MFi approval for this project), they give you input and output streams on a given session to communicate with the accessory, but no such object exists for CoreBluetooth.

Is this simply an oversight on Apple's part on the functionality of CoreBluetooth? Or do I simply need to develop my own Bluetooth service profile to handle the inflow/outflow of data to and from the peripheral?

Answer 1

LE is fundamentally designed to work with these GATT based profiles, which are suited for monitoring sensors, not for data streams. While LE does allow for additional L2CAP streams to be opened for custom protocols, Apple's CoreBluetooth doesn't provide access to do so.