Introduction This paper presents the development and research of an embedded industrial Ethernet controller, proposing the use of SOPC technology to solve the interface speed bottleneck problem in the controller hardware design, thereby improving the controller's real-time performance. Experimental results show that the system operates stably and reliably. With the large-scale application of industrial Ethernet, embedded industrial Ethernet systems are increasingly penetrating the industrial control field. Embedded industrial Ethernet systems based on ColdFire microprocessors and ARM processors have been widely used. However, since the development platforms of these systems are not entirely tailored to industrial Ethernet applications, hardware resource waste or insufficient resources often occur in practical applications. Developed systems often require external PLD chips for logic control of peripheral devices, resulting in an interface speed bottleneck. The NIOS processor based on SOPC technology can solve this problem. Hardware Design The hardware design of the controller was completed in SOPC Builder and Quartus II. These tools allow for flexible customization of various features and even instructions of the NIOS CPU. A large number of IPs provided by Altera can be used to accelerate the development of NIOS peripherals and improve their performance. Third-party IPs, or VHDL and Verilog, can also be used to customize peripherals. The hardware of an embedded industrial Ethernet controller is divided into three parts: the FPGA part, the memory part, and the peripheral component part, as shown in Figure 1. The FPGA used in this paper is the CYCLONE EP1C6. The FPGA part needs to be designed in SOPC Builder. The NIOS system to be built includes the following component modules: a NIOS CPU core, an Avalon bus controller for connecting the NIOS core, an internal Boot ROM storing the startup and debugging programs, a UART serial communication circuit module (RS232 core), an internal timer, and some general-purpose I/O peripheral interface modules. For the NIOS system to function properly, an RS232 communication port, an RJ45 port, several LEDs and digital displays, 16MB of SRAM, and 4MB of Flash ROM must be connected to the FPGA peripherals. Software Design Since the system composed of the NIOS CPU and its peripherals in hardware development is custom-designed, the memory and peripheral address mappings are all different, thus requiring a proprietary SDK (Software Development Kit). After completing the NIOS hardware development, SOPC Builder can automatically generate the SDK. The software development is almost identical to that of typical embedded systems, the only difference being that this embedded system is custom-designed and tailored, thus less constrained by hardware limitations. Considering cost-effectiveness and on-site control requirements, the controller's operating system utilizes the following features of the embedded industrial Ethernet controller: 1) High flexibility. The use of NIOS as the microprocessor allows for flexible allocation of system resources and overcomes the interface speed bottlenecks inherent in other processors, adapting to the real-time data requirements of industrial Ethernet. 2) The Clinux microprocessor is very small in size and possesses Ethernet functionality, easily enabling miniaturization and networking of the controller; 3) High integration. NIOS offers abundant interface resources; 4) High real-time performance. The controller's hardware and software designs fully consider real-time performance. The hardware design employs a high-speed A/D converter (500kHz) and multiple D/A outputs, ensuring timely sampling and output of critical signals, guaranteeing "hard real-time"; the operating system incorporates the RTlinux module, ensuring "soft real-time". Practical Application This controller was applied to an Ethernet-based control system to meet the needs of a company's production site. To address the stringent requirements for network reliability parameters at the site, a ring network topology was adopted to increase network reliability. To solve the real-time network problem, the concept of a control domain was used, dividing the control site into zones to reduce resource contention between control zones. Communication between control zones is achieved through switched Ethernet switches. Each control zone contains an Ethernet switch, an embedded industrial Ethernet controller, and some transmitters and actuators, as shown in Figure 2. This system has the following characteristics: 1) Flexibility. SOPC technology makes the design and debugging of system hardware and software very convenient. 2) Reliability. The ring architecture of the control system's network topology greatly enhances the reliability of the backbone network. At the control network layer, the control risks are distributed by dividing the control zones; while within each control zone, an embedded industrial Ethernet controller centrally controls the entire control zone, reducing control costs. Practice has proven that this distributed-centralized control structure is very effective. 3) Real-time performance. By dividing the control area into zones, each zone is connected to the backbone network via switches. Information from the transmission and execution structures within each control area does not consume backbone network resources. This reduces the network load of each control area to a very low level (<5%), improving network real-time performance. The hardware and software design of the embedded industrial Ethernet controller considers real-time requirements, further enhancing system real-time performance at the network layer. Conclusion This paper presents the development and research of an embedded industrial Ethernet controller, proposing the use of SOPC technology to address the interface rate bottleneck in the controller's hardware design, thereby improving the controller's real-time performance. Experimental results show that the system operates stably and reliably.