BlueNRG is an energy-efficient Bluetooth® 4.0 Low-Energy Single-Mode chip enabling longer runtimes and smaller, lighter batteries in a wide range of wireless “accessories” such as fitness wristbands, smart eyewear, or interactive clothing. It is compliant with Bluetooth specification v4.0. ST’s BlueNRG network processor provides the functions needed to link the Bluetooth Smart device to a Bluetooth Smart Ready host such as a smartphone or a tablet. BlueNRG features its own radio, processor, and Bluetooth firmware to simplify the wireless design, allowing engineers to concentrate on creating innovative applications. ST BlueNRG enables superior battery life and excellent wireless-link performance, allowing devices to operate for months or even years from a small coin-cell battery. In addition to low current consumption, BlueNRG also has frugal power management and can transition rapidly between operating modes, minimizing unproductive power. Moreover, BlueNRG gives designers flexibility to choose their preferred host microcontroller and comes with Bluetooth LE profiles to run in the external application processor. The on-chip non-volatile memory enables easy firmware upgrades to maintain future compliance. BlueNRG can act as master or slave, the Bluetooth LE stack runs on the embedded Cortex M0 core, and it offers the option of interfacing with external microcontrollers using SPI transport layer.