1. Introduction
The OpenThread border router (OTBR) is crucial in Matter to enable the communication between IP-based networks. It acts as a bridge between the Thread network and the outside world.
A Thread Border Router supports at least, the following functions:
- Bidirectional IP connectivity between Thread and Wi-Fi/ethernet networks.
- Bidirectional service discovery via mDNS (on a Wi-Fi/Ethernet link).
- Thread-over-infrastructure that merges Thread partitions over IP-based links.
- External Thread commissioning (for example, a mobile phone) to authenticate and join a Thread device to a Thread network.
2. STM32MP1 OpenThread border router
The STM32MP1 OTBR works with the NUCLEO-WB55RG radio coprocessor (RCP), which is connected to the STM32MP157F-DK2 Discovery kit (wiki for STM32MP15 Discovery kits) or STM32MP135F-DK Discovery kit (wiki for STM32MP13 Discovery kits) through a serial connection using an FTDI.
| OpenThread border router |
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2.1. Boards needed
- as OpenThread border router:
- as Thread® RCP firmware, NUCLEO-WB55RG ST radio coprocessor (RCP):
2.2. STM32MP157F-DK2 and STM32MP135F-DK installation
A Linux® PC running under Ubuntu® 18.04 or 20.04 must be used. The developer can follow this link.
The Linux package can be found in Github.
3. NUCLEO-WB55RG RCP installation
- Step1: Get the X-CUBE-MATTER from st.com
- Step2: Discover the NUCLEO-WB55RG hardware by following this link
- Step3: Install the firmware by following this link.
4. NUCLEO-WB55RG RCP hardware connection
The communication is done through a serial connection. For RCP implementation, UART Rx/Tx are routed to external connector CN10 pin 35 (Tx) and pin 37 (Rx). If the host platform uses USB we will need a USB/UART converter (e.g. FTDI). In this case, connect its Rx connector (usually the yellow one) to CN10 pin 35 and its Tx connector (usually the orange one) to CN10 pin 37. Black connector (i.e. ground) can be found on CN10 pin 32.
| STM32WB RCP hardware connection |
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