The S140 SoftDevice is a Bluetooth® Low Energy Central and Peripheral protocol stack solution. The S140 SoftDevice supports running up to twenty connections concurrently, with an additional observer role and broadcaster role. The S140 SoftDevice integrates a Bluetooth Low Energy Controller and Host, and provides a full and flexible API for building Bluetooth Low Energy nRF52 System on Chip solutions.
The SoftDevice API documentation is available for different versions of the SoftDevice.