Apple’s MFi Program and HomeKit
Apple’s MFi Program offers a broad range of wireless and wired technologies for creating hardware accessories that connect to iPhone, iPad, iPod, and Apple Watch. The program gives access to the technical specifications and resources needed to develop accessories that communicate with Apple devices.
HomeKit is Apple's smart home platform and a part of the MFi Program. With the Home app, users can easily and securely control their HomeKit accessories from all their Apple devices and access all their home’s smart accessories remotely through a home hub like Apple TV, HomePod, or iPad.
The history of HomeKit has emerged with two wireless connectivity options: WiFi for the high-bandwidth, low latency mains powered communication, and Bluetooth LE for low bandwidth connectivity with low power requirements.
Extension of HomeKit
In November 2020, Apple released to MFi Program members the extended specification of HomeKit Accessory Protocol to add support for Thread as an additional connectivity option. This was perfectly timed with another major release from Apple, the HomePod mini. This device is Apple's first home hub supporting the Thread networking protocol natively, enabling customers to control their Thread HomeKit accessories remotely.
The Thread networking protocol
With its HomePod mini, Apple introduces mesh functionality to HomeKit built on Thread. The Thread networking protocol is tailored to suit the needs of the smart home. In addition to its mesh networking capabilities, Thread is a low power, scalable, and robust protocol. It enables end-users to expand their smart home network with minimal effort – a Thread network auto-reconfigures when you add or remove a device.
Thread runs on existing IEEE 802.15.4 silicon, the same radio as used for Zigbee networking protocol, but use the Internet’s proven, open standards to create an Internet Protocol version 6 (IPv6)-based mesh network. As a result, Thread devices seamlessly integrate with larger IP networks and don’t need proprietary gateways or translators.
HomeKit now brings more options and lowers the threshold for expanding people's smart home network by adding new devices. Due to the mesh networking capabilities of Thread, improving the range of the home network is easy.
End-users will also benefit from shortened communication latency, particularly for group control, if you compare Thread and Bluethooth LE connected HomeKit accsessories.
So, what about the existing HomeKit networks? Every Thread HomeKit accessory must support both Thread and Bluetooth LE concurrently. Bluetooth LE is used to add a new accessory to a network and as a fallback option. If a user doesn't have an Apple home hub supporting the Thread interface, a Thread accessory automatically falls back to the Bluetooth LE interface.
Nordic hardware suitable for HomeKit accessories
Nordic customers participating in the MFi Program will immediately benefit from the new HomeKit version. Both the nRF5340 and the nRF52840 are memory-rich and support concurrent operation of Thread and Bluetooth LE, making them a perfect choice to build HomeKit accessories.
Nordic software supporting Apple HomeKit
To reduce dev time and cut costs for the developers, Nordic integrates the latest HomeKit Accessory Development Kit (ADK) with Nordic’s nRF Connect SDK. The SDK comprises both certified Bluetooth LE and Thread protocol stacks.
The software is available to MFi licensees only. To get access to the HomeKit repository within nRF Connect SDK, contact the Nordic support team via the Nordic DevZone private ticket.
Same software and hardware platform for Project CHIP
Also worth noting is that Nordic uses the same HW (nRF5340 and nRF52840) and the same SW platform (nRF Connect SDK) for Project Connected Home Over IP (Project CHIP). It allows devices built for HomeKit to run Project CHIP or upgrade to Project CHIP with minimal additional development effort.
This article was first published on Nordic's Get Connected Blog.