1、 EDA的发展及 VHDL的应用 90s in 20 centuries, international last electronics and calculator technique more the forerunners nation, has been being actively investigating a new design method of the electronics electric circuit, and carried on an exhaustive change in the aspects of designing a method, tool wai
2、t, obtain huge success.At the design realm of the electronics technique, the application of programmable logic spare part(like CPLD, FPGA), have already got extensive universality, these spare parts brought tremendous vivid for the design of numerical system.These spare parts can pass a software pla
3、it a distance but as to its hardware structure and work the way carry on heavy Gou and make thus the design of hardware can like software design so convenient fast.The all these biggest changed a traditional numerical method, design process of the system design and design idea and promoted the EDA t
4、echnical quick development. The EDA is an electronics design automation(the Automation of the Electronic Design) of abbreviation, design(CAD) from the calculator assistance at the beginning of 90s in 20 centuries, calculator assistance manufacturing(CAM), calculator assistance test(CAT) and calculat
5、or lend support to the concept of engineering(CAE) a development since then.The EDA technique is to take calculator as tool, design at EDA software terrace up, use the hardware description language HDL completion a design a document, then is of oneself completed logic to edit and translate, turn Chi
6、en, partitioned by the calculator, comprehensive, excellent turn, set up, cloth line with imitate really, until for particular target chip of proper go together with to edit and translate, the logic reflect to shoot with plait distance download etc. work.The EDA technical emergence, biggest raised e
7、fficiency and maneuverability of electric circuit design, eased to design of labor strength. These spare parts can pass a software plait a distance but as to its hardware structure and work the way carry on heavy Gou and make thus the design of hardware can like software design so convenient fast.Th
8、e all these biggest changed a traditional numerical method, design process of the system design and design idea and promoted the EDA technical quick development.Make use of EDA tool, the electronics designer can start design electronics system from the concept, calculate way, agreement.etc., a great
9、 deal of work can pass calculator completion, and can design the electronics product is from the electric circuit, the function analyze compute of the whole process of design an IC landscape or PCB landscape on board auto processing completion. Use to the EDA concept or category very breadth now.Inc
10、lude in each realm of the machine, electronics, correspondence, aviation aerospace, chemical engineering, mineral, living creature, medical science, military.etc., all there is EDA application.The EDA technique has already extensively used in each archduke department, the Qi business unit and resear
11、ch teaching section currently.For example in the airplane the manufacturing the process, from design, performance test and characteristic analytical until fly emulation, may involve an EDA technique.The EDA technique that this text point mainly to the design, PCB design of the electronics electric c
12、ircuit and IC design. The EDA design can is divided into system class, electric circuit class and physics to carry out class. The EDA in common use software:The EDA tool pile up one after another and get into an our country currently and have the EDA software of extensive influence to have:MultiSIM
13、7(the latest edition of original EWB), PSPICE, OrCAD, PCAD, Protel, Viewlogic, Mentor, Graphics, Synopsys, LSIIogic, Cadence, MicroSim, ISE, modelsim etc.These tools all have stronger function, generally can used for a few aspects, for example a lot of softwares all can carry on an electric circuit
14、design with imitate really, together entering can also carry on PCB to automatically set up cloth line, can output various net form a document with the third square software connect. The VHDL English full name be the HardwareDescription Language of the Integrated Circuit of the Very-High-Speed, birt
15、h in 1982.At the end of 1987, the VHDL is confirm by IEEE and American Ministry of National Defense to describe language for the standard hardware.Announced VHDL standard edition from the IEEE, IEEE-1076(call 87 versions) after, the each EDA company released own VHDL design environment one after ano
16、ther, or declared that the own design tool can connect with VHDL.Henceforth the VHDL designed realm to get to extensively accept in the electronics, and gradually replaced an originally not- standard hardware description language.In 1993, the IEEE carried on to revise to the VHDL, describe ability t
17、o up expand a VHDL contents from higher abstract layer and the system, announced the VHDL of new edition, namely IEEE standard of 1076-1993 editions, .(call 93 versions)Now, VHDL and Verilog are the industrial standard hardware description of the IEEEs language, again arrive support of numerous EDA
18、companies, at electronics engineering realm, have become in general use hardware to describe language in fact.There is expert think, in the new century in, the VHDL will start to undertake a greatly part of numerical system design mission at the Verilog language. The VHDL language is a kind of delux
19、e language which useds for an electric circuit design.It expects to appear after the 80s of.BE at the beginning come out by American Ministry of National Defense development to provide the American solider with the credibility which uses to raise a design with cut 1 kind of development period to use
20、 the scope smaller design language. All of VHDL Englishes write BE:The Descriptiong Language of the VHSIC(the Speed Integrated of the Very High Circuit) Hardware.Translating into Chinese is soon extremely high the description language of the integrated circuit hardware.So it of the application mainl
21、y is an application in the design of numerical electric circuit.Currently, it is in the application most in China is the design which uses in the FPGA/CPLD/EPLD.Certainly in some units with stronger real strenght, it is also use to design ASIC. The VHDL mainly useds for the structure, behavior which
22、 describes numerical system, function with connect.In addition to implying many languages sentence which have a hardware characteristic, VHDL languages forms and description style and sentence construction are very similar at general calculator deluxe language.VHDL procedure structure characteristic
23、s is an engineering design, or call that the design entity(can be a component, an electric circuit mold piece or a system) is divided into exterior(or call but part, and port) with inner part(or call to cant see part), since involve internal function and calculate way of entity to complete part of.A
24、t to 1 designed entity to define exterior interface after, once it internal development completion after, other designs can directly adjust to use this entity.This kind of will design entity to be divided into a little bit basic VHDL system that is a VHDL system inside the concept of outside part de
25、sign design of a little bit basic and other hardware describe the language compare and the VHDL has a following characteristics: The function is strong and the design be vivid.The VHDL has the function strong language structure, can describe a complicated logic control with the simple and direct and
26、 explicit source code.It has a multi-layer design description function, in multiple layers thin turn, finally directly born electric circuit class description.The VHDL supports synchronous electric circuit, differences tread electric circuit with random the design of electric circuit, this be the ot
27、her hardware description although the language cant compare to.The VHDL still supports various design method, since support from the bottom upward design, support again from the design of crest declivity；Since the support mold piece turns a design, support layers turn a design again. Support extensi
28、vely and be easy to a modification.Because the VHDL has already become IEEE standard the norm of hardware description language, most EDA tools almost support VHDL currently, this is VHDL of further expansion with extensively applied lay foundation.In the design process of the hardware electric circu
29、it, the main design document is the source code which writes with the VHDL, the VHDL easily reads with the structure turn, so be easy to a modification design. The strong system hardware describes ability.The VHDL has a multi-layer design description function, since can describe system class electri
30、c circuit, can describe door class electric circuit again.And description since can adopt a behavior description, deposit a machine to deliver description or structure description, can also adopt the hybrid description of threes mixture.Moreover, VHDL support is inertial to delay and deliver to dela
31、y, can also accurately build up hardware electric circuit model.VHDL support prepare definite of with from definition of data type, bring hardware description a bigger freedom degree, make design the personnel can expediently establish the system model of high time. The independence is at the design
32、 of spare part, have nothing to do with the craft.Dont need to consider a choice completion the spare part of design first while designing a personnel to carry on a design with the VHDL, can concentrate energy to carry on design of excellent turn.When the design description complete after, can carry
33、 out its function with various different spare part structure. Very strong transplantation ability.The VHDL is a kind of hardware description for standardize language, the same of design description can be support by the different tool and make to design to describe of the transplantation make possi
34、ble. Be easy to a share and reply to use.The VHDL adoption can build up various mold piece that can again make use of according to the design method of database(Library).These canned in advance design or use to design a medium backup mold a piece before and depositted these to the database in, can b
35、e in laterly of the design carry on replying to use, can make the design result be design the personnels to carry on exchanges and share, decrease hardware electric circuit design. (1)compared with other hardware description languages, the VHDL have stronger behavior description ability, come to a d
36、ecision him to become a system design realm the best hardware a description language thus.The strong behavior description ability is to avert from concrete spare part structure and describe and design important assurance of large-scale electronics system from the logic behavior. (2)the VHDL be abund
37、ant of imitate true language sentence and database function, make in any big system of the design can inspect a function possibility of design the system in early days, can carry on imitating true emulation to the design at any time. (3)the ability and procedure structure of the behavior description
38、 with lexical VHDL come to a decision the decomposition that he has to support a large-scale design with have already have design of again make use of function.Meet the market demanding large-scale system efficiently, the completion of the high speed has to include many people the several generation
39、 hair set even together and abreast works and then can carry out. (4)for use the design of an assurance of VHDL completion, can make use of EDA tool to carry on logic comprehensive with excellent turn, and auto of the VHDL describe the design change into the door class net form. (5)the description o
40、f VHDL to design have opposite and independent, the design can not understand the structure of hardware and need not manage the target spare part that the end design carry out, either is what, but carry on an independent design. 1、 20世纪 90年代，国际上电子和计算机技术较先进的国家，一直在积极探索新的电子电路设计方法，并在设计方法、工具等方面进行了彻底的变革，取
41、得了巨大成功。在电子技术设计领域，可编程逻辑器件（如 CPLD、 FPGA）的应用，已得到广泛的普及，这些器件为数字系统的设计带来了极大的灵活性。这些器件可以通过软件编程而对其硬件结构和工作方式进行重构，从而使得硬件的设计可以如同软件设计那样方便快捷。这一切极大地改变了传统的数字系统设计方法、设计过程和设计观念，促进了 EDA 技术的迅速发展。 EDA 是电子设计自动化（ Electronic Design Automation）的缩写，在 20世纪 90年代初从计算机辅助设计（ CAD）、计算机辅助制造（ CAM）、计算机辅助测试（ CAT）和计算机辅助工程（ CAE）的概念发展而来的。 EDA 技术就是以计算机为工具，设计者在 EDA 软件平台上，用硬件描述语言 HDL完成设计文件，然后由计算机自动地完成逻辑编译、化简、分割、综合、优化、布局、布线和仿真，
