Support The Design Of The Ethernet Access Network Control Terminal

This article discusses an embedded network control terminal based on Ethernut solutions and control system development process in detail, the embedded network control terminal with the analog input and output, digital input and output, different network connections (RS-485,and Ethernet), connect RS-232 serial equipment, the expansion of wireless communication module, such as multi-functional interface, the implementation of the Ethernet access control object and the form of computer network control system.The design of system software include embedded network control terminal program and computer application software, the network control terminal's program have a variety of peripheral driver modules, Ethernet communication protocol program and main program. The network control terminal implemented ARP, IP, TCP, UDP and other protocols. Computer application software which is writed by VB6.0, set up TCP connections with the network control terminal to achieve reliable data communication. The system is designed to be simple, software flexibility, lower cost and has strong applicability of similar systems for the design of the actual value of the reference and promotion.In this paper, the main job is the followings:1. The hardware design of embedded network control terminal includes the design of ATmega128 microcontroller interface circuit, the design of network interface chip RTL8019AS circuit , the design of complex programmable logic device (CPLD) XC9536 circuit , the design of static random access memory (SRAM) circuit, the design of RS -232 interface circuit, the design of RS-485 interface circuit, the design of analog input and output circuit, the design of digital input and output circuit, the design of power circuit.2. The design of the embedded network control terminals software includes the design of embedded operating system software which is named NUT / OS, embedded TCP / IP protocol stack which is named NUT / NET, embedded application software. The embedded application software introduce the design of RTL8019 driver, the design of analog-digital conversion driver, the design of digital-to-analog converter driver, the design of serial communication driver, and the main program.3. The development of computer application software is designed by VB6.0, which is used to test a variety of functions of the network control terminal.