This blog is to describe about the nRF51824 which is the automative grade chipset on the nRF51 Series.

nRF51824 is an automotive grade AEC-Q100 qualified (Grade 2: -40 to +105°C) ultra-low power 2.4 GHz wireless System on Chip (SoC) that supports Bluetooth® Low Energy and a range of proprietary 2.4 GHz protocols, such as Gazell. It is an ideal choice for intelligent automotive applications that may include alerts, collision detection, control and telemetry, wireless charging and infotainment, amongst many others.

Fully qualified Bluetooth Low Energy stacks for nRF51824 are implemented in the S100 series of nRF51 Series SoftDevices and can be installed on nRF51824 independent of your own application code.

The product specification of nRF51824 can be found at

Bluetooth Stack (SoftDevice)

The S130 SoftDevice is a Bluetooth® Low Energy Peripheral protocol stack solution. The S130 SoftDevice integrates a Bluetooth Low Energy Controller and Host, and provides a full and flexible API for building Bluetooth Low Energy nRF51 System on Chip solutions.

The S130 SoftDevice is a precompiled and linked binary image implementing a Bluetooth® 4.2 low energy protocol stack for the nRF51 Series of SoCs.

The latest softdevice for the nRF51 series is S130v2.0.1 ( )

Bluetooth® 4.2 compliant low energy single-mode protocol stack suitable for Bluetooth® Smart products

  • Concurrent Central, Observer, Peripheral, and Broadcaster roles with up to eight concurrent connections along with one observer and one broadcaster
  • Configurable number of connections and bandwidth per connection to optimize memory and performance
  • Configurable attribute table size
  • Custom UUID support
  • Link layer
  • L2CAP, ATT, and SM protocols
  • LE Secure Connections pairing model
  • GATT and GAP APIs
  • GATT Client and Server

The softdevice specification of S130v2.0.1 can be found at

s130 softdevice的图片搜寻结果

BLE Role configuration

The S130 SoftDevice stack supports concurrent operation in multiple Bluetooth® low energy roles. The roles available can be configured when the S130 SoftDevice stack is enabled at runtime. The SoftDevice provides a mechanism for enabling the number of Central or Peripheral roles the application can run concurrently. The SoftDevice can be configured with one connections as a Peripheral and up to eight connections as a Central. The SoftDevice supports running one Advertiser or Broadcaster and one Scanner or Observer concurrently with the BLE connections.

The SoftDevice supports three predetermined bandwidth levels: low, mid(medium), and high. The bandwidth levels are defined per connection interval, so the connection interval of the connection will also affect the total bandwidth. Bandwidth configuration is an optional feature and if the application chooses to not use the feature the SoftDevice will use default bandwidth configurations. By default, connections as a Central will be set to medium bandwidth and connections as a Peripheral will be set to high bandwidth. The bandwidth can also be configured individually for both transmitting and receiving, allowing for more fine-grained control with asymmetric bandwidth.

The latest SDK for nRF51824 is version 12.3.

(Download at

I did one of example by using the Segger Embedded Studio (