【作者】 黄志葵；

【导师】 文远保；

【作者基本信息】 华中科技大学 ， 计算机系统结构， 2006， 硕士

【摘要】 嵌入式系统是一种专用的计算机系统。它以计算机技术为基础,面向具体的应用,软件和硬件可以根据需求进行剪裁。嵌入式系统应用于特定的场合,这一点决定了它在功能、可靠性、成本、体积、功耗等方面有严格要求。面向GPS(Global Positioning System)移动终端应用的嵌入式系统平台结合了地理信息系统、全球定位系统、通用分组无线服务和多媒体等多种技术,实现位置查询、无线通信、音频、视频等多种功能。在嵌入式系统设计过程中需要较多的理论支持。嵌入式系统体系结构理论为应用设计提供指导方向;高速数字设计中的电路理论为设计性能可靠的硬件提供设计依据和技术支持;电源理论为设计性能稳定可靠的供电子系统提供保证。系统设计包括硬件设计和软件设计。硬件设计的关键是处理器电路设计。同时,系统集成了以太网电路、音频电路、视频电路、USB(Universal Serial Bus)电路、GPS模块、GPRS(General Packet Radio Service)模块等外围电路。通过电路级仿真和板级信号完整性分析,克服了高速数字电路设计中的关键性问题。这些问题包括信号之间的串扰、传输线上的反射、阻抗匹配等。在处理传输线效应的过程中,线路阻抗是否匹配成为所设计产品是否获得最佳特性的一个重要因素。印制电路板(Printed Circuit Board,PCB)设计流程的规范化非常重要。规范化能使由于意外因素导致设计失败的可能性降到最低。通过总结与制定元器件封装库创建规则,归纳PCB设计流程,确保了设计文件输出的正确。软件开发包括代码下载程序开发、启动代码开发以及操作系统的移植。在完成主机上运行的代码下载程序的开发之后,就能将启动代码通过串口下载到裸板上,并在此基础上完成启动代码、操作系统的移植。启动代码在引导操作系统时向其传递必要的参数,完成系统的启动。更多还原

【Abstract】 Embedded system is an application specific computer system. It is based on computer technology facing idiographic applications, and scalable on software and hardware. Embedded system is applied under the specific circumstances, which determines that it is strict with function, reliability, cost, size, power consumption, etc. The platform facing GPS (Global Positioning System) mobile terminal application implements fuctions such as position inquiry, wireless communication, audio and video, etc by combining GIS (Geographic Information System), GPS, GPRS (General Packet Radio Service), audio and video.A few theories are needed in embeded system design process. Embedded system architecture theory provides guideline to application, and circuit theory about high-speed system design provides design gist and technical support to design reliable hardware, and power theory ensures supply subsystem running well.The design includes hardware design and software design. The key of hardware design is processor circuit design. In addition, it integrates circuits such as ethernet, audio, video, USB (Universal Serial Bus), GPS, GPRS and etc. A few key problems are resolved by simulating at schematic level and singal integrity analyzing at board level. The key problems include crosstalk between signals, reflection on transmission line and impedance matching. In the process of dealing with effect of transmission line, whether signal impedance is matched or not is a vital factor to get optimal characteristic for design.Standardization of PCB (Printed Circuit Board) design process is important. Process standardization can make failure probability lowest for accidental factor. Summarizing experience how to build component footprint and concluding procedure of design ensures outputing files correctly.Software development includes download executable code, bootloader, operating system. After development of download executable code running on the host is completed, bootloader can be downloaded to bare board by serial line. Porting bootloader and operating system is succeeded on the basis. Bootloader boots system while passing necessary parameter to operating system.更多还原