Introduction to Matter

1 Introduction

Matter is a new smart home communication standard that allows different devices to work together easily, regardless of their manufacturer. It is designed to simplify the smart home experience while maintaining security and privacy. One of the benefits of Matter is that it is an open standard, which means that any device manufacturer can use it. Matter is an initiative of the Connectivity Standards Alliance (CSA). It is developed through a collaboration among all the leaders of the IoT industry.

Matter is an application protocol running on top of several transport layers such as Wi-Fi®, Ethernet, and Thread®. Matter relies on IPv6.

The Matter software is provided as open source by CSA and is available under Github.

2 Device roles in Matter network

Smart homes utilize Wi-Fi or Thread technologies to operate connected devices. Each device has a distinct role within the Matter network.

Matter network
Connectivity matter overview.png
  • End devices are connected objects serving a final application like thermostats, light bulbs, door locks, and other smart home devices that can be controlled through a smart home platform.
  • Bridges are devices that enable communication between devices using different communication protocols. For example, a bridge can enable a device that uses Wi-Fi to communicate with a device that uses Zigbee®.
  • Controllers are devices such as smartphones or tablets used to commission an end device into a Matter network through Bluetooth® Low Energy. Controllers are devices that serve as the central hub for the smart home network.
  • Border router is a device that acts as a gateway between a Thread network and other IPV6-based networks, such as the internet or other local networks. The border router plays a crucial role in a Matter ecosystem.

3 Matter stack overview

The Matter protocol is designed to be compatible with existing IP-based networks, making it easier for manufacturers to adopt and integrate into their products.

The Matter stack is composed of the following layers:

  1. Application layer: This layer includes the application-specific functionality and user interfaces that are built on top of the Matter protocol. It includes the presentation and the session layers.
  2. Transport layer: This layer includes the transport protocols used to transmit data over the network, such as TCP and UDP. BTP is provided as a transport protocol for commissioning. TCP and UDP are provided as transport protocols for operational messaging.
  3. Network layer: This layer includes the IPv6 network layer, which provides end-to-end connectivity for devices and services on the network.
  4. Link layer: This layer includes the data link layer, which provides the transmission of data frames over the physical layer.

    The link and physical layers can vary depending on the type of network being used, such as Ethernet, Wi-Fi, 802.15.4, or Thread.

Bluetooth® Low Energy is used for device commissioning.

Matter stack overview
Connectivity Matter Stack overview.png


4 STM32WB Matter

The STM32WB series of microcontrollers is ideal for Matter networks because it has devices able to run concurrently Thread and Bluetooth® Low Energy used for device commissioning. The STM32WB55RG and STM32WB5MMG microcontrollers presented in this section feature 1 Mbyte of flash memory and 256 Kbytes of RAM to support application layer and connectivity stacks as well as Quad-SPI peripherals to extend the memory size externally. These features allow over-the-air firmware updates, regardless of the application and the connectivity stack.

The STM32WB55RG microcontroller equips the NUCLEO-WB55RG[1] Nucleo-64 board. The STM32WB5MMG microcontroller equips the STM32WB5MM-DK[2] Discovery kit with sensors, external flash memory, a screen, and touch sensors.

Product types
Connectivity Matter products.png

We propose several samples demonstrating the usage of Matter:

  • Matter gateway STM32MP1 border router [3]:

The OpenThread border router (OTBR) is composed of a NUCLEO-WB55RG radio coprocessor (RCP) and an STM32MP157F-DK2 Discovery kit, which are connected through a serial connection using an FTDI cable.

  • Matter end device [4]:

This package shows several matter end device sample applications. These examples are based on Matter and behave as a Matter accessories communicating over an 802.15.4 Thread network.

  • Matter bridge [5]:

The Matter bridge sample provides an example of Matter bridge with the NUCLEO-H753ZI-Q board with Ethernet connectivity. Basically, It adds the non-Matter device as endpoints on a bridge acting as a Matter device.

5 Acronyms and definitions

Term Definition
BTP Bluetooth Transport Protocol
TCP Transmission Control Protocol
UDP User Datagram Protocol

6 References