【正文】 . Digital circuit design using FPGA devices, can not only simplify the design process and can reduce the size and cost of the entire system, increasing system reliability. They do not need to spend the traditional sense a lot of time and effort required to create integrated circuits, to avoid the investment risk and bee the fastestgrowing industries of electronic devices group. Digital circuit design system FPGA devices using the following main advantages (1) Design flexible Use FPGA devices may not in the standard series device logic functional limitations. And changes in system design and the use of logic in any one stage of the process, and only through the use of reprogramming the FPGA device can be pleted, the system design provides for great flexibility. (2) Increased functional density Functional density in a given space refers to the number of functional integration logic. Programmable logic chip ponents doors several high, a FPGA can replace several films, film scores or even hundreds of smallscale digital IC chip illustrated in the film. FPGA devices using the chip to use digital systems in small numbers, thus reducing the number of chips used to reduce the number of printed size and printed, and will ultimately lead to a reduction in the overall size of the system. (3) Improve reliability Printing plates and reduce the number of chips, not only can reduce system size, but it greatly enhanced system reliability. A higher degree of integration than systems in many lowstandard integration ponents for the design of the same system, with much higher reliability. FPGA device used to reduce the number of chips required to achieve the system in the number printed on the cord and joints are reduced, the reliability of the system can be mproved. (4) Shortening the design cycle As FPGA devices and the programmable flexibility, use it to design a system for longer than traditional methods greatly shortened. FPGA device master degrees high, use printed circuit layout wiring simple. At the same time, success in the prototype design, the development of advanced tools, a high degree of automation, their logic is very simple changes quickly. Therefore, the use of FPGA devices can significantly shorten the design cycle system, and speed up the pace of product into the market, improving product petitiveness. (5) Work fast FPGA/CPLD devices work fast, generally can reach several original Hertz, far larger than the DSP device. At the same time, the use of FPGA devices, the system needed to achieve circuit classes and small, and thus the pace of work of the entire system will be improved. (6) Increased system performance confidentiality Many FPGA devices have encryption functions in the system widely used FPGA devices can effectively prevent illegal copying products were others (7) To reduce costs FPGA device used to achieve digital system design, if only device itself into the price, sometimes you would not know it advantages, but there are many factors affecting the cost of the system, taken together, the cost advantages of using FPGA is obvious. First, the use of FPGA devices designed to facilitate change, shorten design cycles, reduce development costs for system development。 The external model can be engineered as microprocessors from its programming microprocessors. Verilog HDL is a hardware description language for the algorithm level, doors at the level of abstract level to switchlevel digital system design modelling. Modelling of the target figure by the plexity of the system can be something simple doors and integrity of electronic digital systems. Digital system to the levels described, and in the same manner described in Hintime series modelling. Verilog HDL language with the following description of capacity : design behaviour characteristics, design data flow characteristics, position and structure designed to control and contain the transmission and waveform design a certification mechanism. All this with the use of a modelling language. In addition, Verilog HDL language programming language interface provided by the interface in simulation, design certification from the external design of the visit, including specific simulation control and operation. Verilog HDL language grammar is not only a definition, but the definition of each grammar structure are clear simulation, simulation exercises. Therefore, the use of such language to use Verilog simulation models prepared by a certification. From the C programming language, the language inherited multiple operating sites and structures. Verilog HDL provides modelling capacity expansion, many of the initial expansion would be difficult to understand. However, the core subsets of Verilog HDL language very easy to learn and use, which is sufficient for most modelling applications. Of course, the integrity of the hardware description language is the most plex chips from the integrity of the electronic systems described. History Verilog HDL language initially in 1983 by Gateway Design Automation panies for product development simulator hardware modelling language. Then it is only a dedicated language. Since their simulation, simulation devices widely used products, Verilog HDL as a userfriendly and practical language for many designers gradually accepted. In an effort to increase the popularity of the language activities, Verilog HDL language in 1990 was a public area. Open Verilog International (OVI) is to promote the development of Verilog international organizations. 1992, decided to promote OVI OVI standards as IEEE Verilog standards. The effort will ultimately succeed, a IEEE 1995 Verilog language standard, known as IEEE Std 13641995. Integrity standards in Verilog hardware description language reference manual contains a detailed descript