S140 SoftDevice Specification

S140 SoftDevice Specification

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.

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Key features Applications
  • Bluetooth 5.1 compliant single-mode Bluetooth Low Energy protocol stack
    • Concurrent central, observer, peripheral, and broadcaster roles with up to 20 concurrent connections along with one Observer and one Broadcaster
    • Extended Advertising support
      • Advertising and scanning up to 255 bytes of advertising data in an advertising event
      • Advertising, scanning, and connecting on all supported PHYs
      • Anonymous advertising
    • Configurable number of connections and connection properties
    • Configurable attribute table size
    • Custom UUID support
    • Link layer supporting LE 1M PHY, LE 2M PHY, and LE Coded PHY
    • LL Privacy, including for the Extended Advertising modes
    • LE Data Packet Length Extension
    • ATT and SM protocols
    • L2CAP with LE Credit-based Flow Control
    • LE Secure Connections pairing model
    • GATT and GAP APIs
    • GATT Client and Server
    • Configurable ATT MTU
  • Complementary nRF5 SDK including Bluetooth profiles and example applications
  • Master Boot Record for over-the-air device firmware update
    • SoftDevice, application, and bootloader can be updated separately
  • Memory isolation between the application and the protocol stack for robustness and security
  • Thread-safe supervisor-call based API
  • Asynchronous, event-driven behavior
  • No RTOS dependency
    • Any RTOS can be used
  • No link-time dependencies
    • Standard ARM® Cortex®-M4 project configuration for application development
  • Support for concurrent and non-concurrent multiprotocol operation
    • Concurrent with the Bluetooth stack using Radio Timeslot API
    • Alternate protocol stack in application space
  • Support for control of external power amplifiers and low noise amplifiers
  • Quality of service feature for channel monitoring
  • Sports and fitness devices
    • Sports watches
    • Bike computers
    • Fitness machines
  • Personal area networks
    • Health and fitness sensor and monitoring devices
    • Medical devices
    • Key fobs and wrist watches
  • Home automation
  • AirFuel wireless charging
  • Remote control toys
  • Computer peripherals and I/O devices
    • Mice
    • Keyboards
    • Multi-touch trackpads
  • Interactive entertainment devices
    • Remote controls
    • Gaming controllers
  • Sensors in remote locations
  • Revision history
  • Documentation
    Additional recommended reading for developing applications using the SoftDevice on an nRF52 SoC includes the product specification, errata, compatibility matrix, and the Bluetooth Core Specification.
  • Product overview
    The S140 SoftDevice is a precompiled and linked binary image implementing a Bluetooth 5.1 Low Energy protocol stack for the nRF52 Series of SoCs.
  • Application programming interface
    The SoftDevice API is available to applications as a C programming language interface based on SVCs and defined in a set of header files.
  • SoftDevice Manager
    The SDM API allows the application to manage the SoftDevice on a top level. It controls the SoftDevice state and configures the behavior of certain SoftDevice core functionality.
  • System on Chip library
    The coexistence of the Application and SoftDevice with safe sharing of common SoC resources is ensured by the SoC library.
  • System on Chip resource requirements
    This section describes how the SoftDevice, including the MBR, uses the SoC resources. The SoftDevice requirements are shown for when the SoftDevice is enabled and disabled.
  • Flash memory API
    The SoC flash memory API provides the application with flash write, flash erase, and flash protect support through the SoftDevice. Asynchronous flash memory operations can be safely performed during active Bluetooth Low Energy connections using the Flash memory API of the SoC library.
  • Multiprotocol support
    Multiprotocol support allows developers to implement their own 2.4 GHz proprietary protocol in the application both when the SoftDevice is not in use (non-concurrent) and while the SoftDevice protocol stack is in use (concurrent). For concurrent multiprotocol implementations, the Radio Timeslot API allows the application protocol to safely schedule radio usage between Bluetooth Low Energy events.
  • Bluetooth Low Energy protocol stack
    The Bluetooth 5.1 compliant Host and Controller implemented by the SoftDevice are fully qualified with multirole support (Central, Observer, Peripheral, and Broadcaster).
  • Radio Notification
    The Radio Notification is a configurable feature that enables ACTIVE and INACTIVE (nACTIVE) signals from the SoftDevice to the application notifying it when the radio is in use.
  • Master boot record and bootloader
    The SoftDevice supports the use of a bootloader. A bootloader may be used to update the firmware on the SoC.
  • SoftDevice information structure
    The SoftDevice binary file contains an information structure.
  • SoftDevice memory usage
    The SoftDevice shares the available flash memory and RAM on the nRF52 SoC with the application. The application must therefore be aware of the memory resources needed by the SoftDevice and leave the parts of the memory used by the SoftDevice undisturbed for correct SoftDevice operation.
  • Scheduling
    The S140 stack has multiple activities, called timing-activities, which require exclusive access to certain hardware resources. These timing-activities are time-multiplexed to give them the required exclusive access for a period of time. This is called a timing-event. Such timing-activities are Bluetooth Low Energy role events like events for Central roles and Peripheral roles, Flash memory API usage, and Radio Timeslot API timeslots.
  • Interrupt model and processor availability
    This chapter documents the SoftDevice interrupt model, how interrupts are forwarded to the application, and describes how long the processor is used by the SoftDevice in different priority levels.
  • Bluetooth Low Energy data throughput
    This chapter outlines achievable Bluetooth Low Energy connection throughput for GATT procedures used to send and receive data in stated SoftDevice configurations. This chapter does not provide throughput measurements for LE Coded PHY because this PHY is designed to extend range at the cost of reduced throughput. The throughput on LE Coded PHY is at least 8 times less than on LE 1M PHY.
  • Bluetooth Low Energy power profiles
    The power profile diagrams in this chapter give an overview of the stages within a Bluetooth Low Energy Radio Event implemented by the SoftDevice. The profiles illustrate battery current versus time and briefly describe the stages that could be observed.
  • SoftDevice identification and revision scheme
    The SoftDevices are identified by the SoftDevice part code, a qualified IC partcode (for example, nRF52832), and a version string.
  • Glossary
    The glossary contains terms and acronyms that are used in this document.
  • Acronyms and abbreviations
    These acronyms and abbreviations are used in this document.
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