RE: L2CAP support on the S140 softdevice

Ulrich Myhre — Tue, 13 Jun 2017 23:44:41 GMT

The L2Cap API was a proprietary feature that made use of an under-utilized channel range for data transfers. Since the Bluetooth spec introduced the "Connection Oriented Channels" feature, this proprietary feature can be fully replaced with the formal version. It is largely the same thing, but has some key differences:

There is an initial setup of the channel, where maximum logical and physical packet sizes are agreed upon.
There is a flow control system using credits. It can largely be overridden if you handle the flow control yourself.

The proprietary feature was kept until it had a proper implementation that could replace it. Connection Oriented Channels is already included in the S132 5.0.0-3.alpha, but I do not know if/when it will go into the S140.