Currently, in in-vehicle Ethernet environments, the network interface is the T1 interface. The T1 interface requires only a single pair of differential lines to achieve data transmission speeds of 100Mbps or 1000Mbps, whereas the TX interface requires four pairs of differential lines. This is completely different from the in-vehicle T1 interface.
Figure 1 T1 Interface
Figure 2 Commonly Used TX Interfaces
Due to the significant differences between these two interfaces, when we need to use a computer to debug automotive Ethernet devices, the computer cannot be directly connected to the automotive Ethernet interface. In such cases, a T1-to-TX converter is required to facilitate the connection. This article will introduce the design of T1/TX conversion devices.
Realtek offers automotive-grade Ethernet PHYs (such as the RTL9010AA) as well as commercial-grade Ethernet PHYs (such as the RTL8211FS). To achieve T1-to-TX conversion, you can connect these two PHYs via SGMII or RGMII interfaces. Since the PHYs require configuration, an MCU is also needed, which can configure both PHYs through MDIO.
Figure 3 Block Diagram of T1/TX Conversion Equipment Implementation
Since SGMII routing is relatively simple, the SGMII interface is used here.
The T1/TX conversion equipment designed based on this principle is shown in the diagram below.
Figure 4 Physical View of the T1/TX Conversion Device
Here, a Type-C interface is used to provide power to the board and configure its functions, including setting the speed to either 100Mbps or 1000Mbps, as well as configuring the T1 interface as either Master or Slave. In addition, you can use the Check command to verify whether the T1 and TX interfaces are already Link UP, making it very convenient to use.
Figure 5 Command Line Functions
That concludes my presentation of this solution. Isn't it both simple and convenient?
Realtek offers automotive-grade Ethernet PHYs, switches, and other products, as well as commercial-grade Ethernet PHYs, switches, and network cards. If you need related chips, please feel free to contact us. We not only provide HDKs, but also offer corresponding technical support. You are welcome to reach out to the Dalian Beijing Realtek team via email:lynx.liu@ait-group.com