简单电子琴 外文文献

毕业设计(论文)外文资料翻译

系别：电子信息系

专业：通信工程

班级：B100308

姓名：董又银

学号：B10030802

外文出处：HighWire Press

附件： 1. 原文；2. 译文

2014年03月

外文翻译（英)

DESIGNING A DIGITAL SYSTEM WITH VHDL The digital systems are complex ones,consisting of lots of components.As far as the automated design of such systems is concerned, methods for designing time reducing and limiting the complexity of the task are sought out and applied.A method of the kind is connected with the decomposition and hierarchy principles.The decomposition of the systems is realized in a way,which differentiates functionally independent modules.

A digital system can be described as a module with inputs and/or outputs.The electrical values on the outputs are some function of the values on the inputs.

One way of describing the function of a module is to describe how it is composed of sub-modules.Each of the sub-modules is an instance of some entity,and the ports of the instances are connected using signal s.This kind of description is called a structural description.

In many cases,it is not suitable to describe the structure used.One element is a module,which is at the bottom of the hierarchy in other structures described.For example,if you are using store bought from IC IC package design a system,you do not need to describe the internal structure of the IC.In this case, the module performs the described function is required,without reference to its actual internal structure.This description is called the function or behavior description.

Usually,for structural and behavioral description,either Verilog or VHDL is used.In this paper a designing with VHDL is presented.Here are exposed sequentially all the phases of the very digital system's designing.The main methods are also on show here.The project descriptions,types are presented.The stress is put on the use of VHDL for synthesis of structural and behavioral models.Here are presented several VHDL models of computer systems’ components.

In digital systems design,and the design of complex systems,several commonly used methods:

Top- down design , bottom- up design

Bottom- down approach in the design direction of the system is usually established from the start at the bottom,the preparation module design,formed by the assembly after the entire product.

The advantage of this method is to use a functional block level to achieve a lower

level of the structure , process only error checking in the project during the simulation.

Top-down design starts with the highest level of specification.Thereafter,the program is broken down into functional blocks,and the ratio of the input and output time may be specified.Functional model is through behavioral model or registration level model description,followed by a simulation.

The advantages of this approach are:

Standardized tasks easier to implement;

Details need to deal with the structure,allowing the project to be checked at the institutional level;

Without regard to its implementation,inspection items to complete.Allows for late design projects to choose technology.

Since the most effective way is to use a top-down design and specify the order details the different levels of description summary description of the program.

The next stage of digital systems design experience:the specification,features, physical design and manufacturing,testing.

Through standardized product parameters to determine the correct goals.

By function design,electronic design,the reference product specifications to develop the product functions and parameters.

The behavior described in the stage of system solutions and conducted its entry and exit have been marked.In most cases,the use of VHDL pleting the main function of the function block(electrical)are designed to ually done by a detailed description of VHDL function blocks and checked by VHDL simulation.

With the increasing complexity of the project,at the structural level,synthesis techniques need to be applied.Program contains the logic elements it needs to be a comprehensive description through VHDL language.Detailed description of such charge through the logic delay elements is the key method is specified,and defines the problem of time discrete signal.

Physical design phase tightly dependent on technology.Deployment logic elements and definitions links between them(tracking) and common tasks are closely related.

Under the conditions of implementation of programmable logic devices,you can use the CPLD or FPGA chip,the result then it means that the physical design of the resource profile design of the selected device.