Chapter 4 System Engineering

4.1 Overview

Although the system engineering subject matter in this chapter may be applied towards a conventional engineering development, the principals and practices presented here are intended to aide the FPGA engineer in a Rapid System Prototyping design effort. We should first define a common definition that is used throughout this chapter and book as to the meaning of a rapid development effort. The definition of Rapid System Prototyping; is “the development of system functionality at a faster pace than that of a conventional engineering development process, aimed toward meeting demanding time-to-market design cycles while mitigating risks associated with a demanding development schedule.” This is what we mean by rapid system development through out this book.

Rapid development requires an efficient and well organized undertaking of identified design tasks. This chapter focuses on the specific decisions and actions that may minimize development risk and schedule. Understand the concepts presented can help designers avoid design issues that can slow the development cycle and identify common design pitfalls.

FPGA technology can provide a significant advantage in speeding a design to final tested functionality. While FPGAs are inherently flexible devices, issues may arise due to this flexibility. Care must be taken during the design phase to maintain and enhance this flexibility since this is the primary advantage an FPGA provides. Maintaining an FPGA’s flexibility throughout the design cycle requires focused effort on the part of the design team. With a medium amount of additional up-front effort, an FPGA-based embedded design can maintain maximum flexibility and adaptability.

There are two primary ways to learn: You can make your own mistakes and learn from them, or you can observe and research the mistakes of others and learn from the examples of others. The contents of this and the following chapters have revolved from real-world experience with FPGA rapid design projects. With the common accelerated schedules of rapid system prototyping projects design requirements, design documentation, and design processes become critical design factors.

第四章系统工程开发方法

4.1概述

本章的主题是系统工程开发方法。尽管在常规工程开发过程中也使用系统工程开发这一概念，在这一章里给出了适用于“快速系统原型开发”过程的开发原则和实践指导，可以给FPGA工程师们以帮助。首先，我们需要对本书中使用的“快速系统原型开发”一词的定义达成共识。我们在全书中对快速系统原型开发的定义是，“比常规工程开发过程速度更快、周期更短的系统功能开发过程。这一过程的目标是满足上市时间的严格要求，同时还要减小由于开发时间缩短带来的各种风险”。

实现系统原型的快速开发需要明确设计中的各项任务，并且高效而有组织地予以实施。本章着重介绍开发过程中可以最小化开发风险和缩短开发时间的各项具体决策和操作。理解这些决策和操作的含义，有助于设计者避开可能减缓开发进度的各种设计问题，并且识别出常见的设计漏洞。

FPGA 技术，由于其固有的灵活性，可以加速产品由功能实现到功能验证直到最终上市的过程。灵活性是FPGA的主要优势。因此，在产品设计阶段必须充分地考虑FPGA的灵活性，以最大化这一优势；设计团队也需要通力合作，在开发过程中自始至终地保持这一优势。只要增加适量的前期工作，基于FPGA的嵌入式设计就可以最大程度地保持其灵活性优势并避免灵活性带来的各种问题，从而获得广泛的应用。

有两种积累开发经验的基本方法：你可以从自己走过的弯路中得到经验，或者通过观察和研究他人的错误和学习他人的成功事例来获得经验。本章和后面各章的内容是从实际的工程实践中总结得来的经验，可以供开发者在采用FPGA进行快速原型设计的过程中参考。由于在快速系统原型设计项目中开发进度普遍加快，设计需求、设计文档和设计过程成为了设计中至关重要的因素。本章在这些方面介绍的经验，可以帮助开发者少走弯路，节省开发时间。