About STM32WB Thread Network Protocol

[GercekC]

Hi everyone,

I have questions about thread network protocol on STM32WB series mcus.

When using open thread protocol in STM32WB series processors, the device can be configured as open thread border router (OTBR).
In the same way, STM32WB mcu can be configured as end device.

1- Let's configure one of the two stm32wb mcu devices as end device and the other as OTBR. Let's assume that we have an active end device and OTBR. Will these two devices be enough for me to control the end device from the mobile application? Does it need any other device like Leader, Router etc.?

2- In this example, Raspberry pi is used as OTBR. Why was STM32WB not used? Does the OTBR device need to be an embedded linux device? 

https://wiki.stmicroelectronics.cn/stm32mcu/wiki/Connectivity:STM32WB_OpenThread_Border_Router_Application

3- If the STM32WB mcu can be configured as OTBR, what is the number of end devices connected to this border router? Is there a maximum number of end device connections? 

I would be very grateful if people who have worked on this subject before or have knowledge can help.

[Ouadi · Accepted solution]

Hello @GercekC 

Thanks for your post and welcome to the community.

Please find below my answers to your questions :

1(2)-  Indeed the OpenThread border router is composed of Host processor + WiFi/ Ethernet + OpenThread RCP

As the STM32WB does not support the WiFi/Ethernet, it need to be coupled to a Raspberry Pi(RPi) or STM32MP1 through a serial communication using FTDI cable. 

Please have a look to the Wiki page for more details : 

https://wiki.stmicroelectronics.cn/stm32mcu/wiki/Connectivity:STM32WB_OpenThread_Border_Router_Application 

You can also refer to Matter protocol which is the new smart home communication standard based on OpenThread :

https://wiki.stmicroelectronics.cn/stm32mcu/wiki/Connectivity:Introduction_to_Matter 

The wiki page includes also a demonstration of controlling a lighting end device over a mobile application. 

3- In a thread mesh network, theoretically the max number of end device supported is limited at 511 per router

Best regards,

Ouadi

[GercekC]

Hi Quadi,

Thank you for your answer. Everything is clear to understand.

1-) As you said, STM32WB does not support ethernet or Wifi. What if can we use STM32H7 series in order to internet connection instead of Raspberry Pi ?

2-) What is the purpose of Matter Bridge in this example? Does the system need Matter Bridge or not ?

https://wiki.stmicroelectronics.cn/stm32mcu/wiki/Connectivity:STM32H7_Matter_bridge

3-) The thread network protocol must be include least 2 device these one is OTBR and End Device. Right ? The others (Bourder Router, Leader Router etc. not neccessary for system if i will not use the meshing) Please correct me if I am wrong.

[Ouadi]

Hello @GercekC,

1(2) - STM32H7 is used in this example to bridge smart home devices to a Matter network, this solution could be useful for Zigbee-based devices that does not support Matter, STM32H7 is then coupled with the STM32WB and implements a matter logic.

3 -  Actually the OTBR connects a thread network to other IP-based networks and it is not a role of a thread network by itself. When the thread network is initiated by the OTBR, it takes the leader role and waits for an end device (Child) to join its network. 

Regards,

Ouadi

[GercekC]

Hi @Ouadi 

Thank you for your answers 😊