【作者】 王玮；

【导师】 黄浩；

【作者基本信息】 华中科技大学 ， 计算机系统结构， 2007， 硕士

【摘要】 模拟电视被数字电视所取代在当前世界范围内已经成为一个不可抗拒的趋势。在模拟电视数字化的过渡阶段,数字电视机顶盒成为享受数字化影音的首选。硬件平台的日益完善和成熟,使得嵌入式软件成为影响产品开发进程的主要因素。研究一个通用、可移植的嵌入式消息处理系统成为当务之急。当前PC机系统上的消息处理是通过消息管理中心分发消息给各应用进程,各进程单独进行消息处理来完成的。这种集中管理,分散处理的机制也会成为嵌入式消息处理系统的发展趋势。基于ST实时操作系统建立的两级消息处理中心模型就是按照这种机制来设计的,同时实现了模块化、可移植的目的。中心模型的第一级实现了通过系统状态和消息本身来筛选传送该消息的下一级消息传送队列;第二级的消息传送队列根据该消息传送队列对应的状态机的当前状态来判断是否发送消息给消息响应模块。“焦点”消息分发机制是实现两级模式的关键技术。“焦点”机制根据状态机间的优先级、状态机内的当前状态来判断、筛选、分发消息。“焦点”机制实现了过滤冗余消息,减少系统消耗等功能。为了加快消息系统的移植速度,利用驱动接口转换中间层实现对应用层屏蔽与硬件相关的更多细节。这个简单但全面的接口转换层使得消息系统与实时操作系统相对独立。最终的系统测试表明,该两级消息处理中心模型实具有模块化、独立化、通用化等优点。便于嵌入式数字电视机顶盒软件的快速开发和跨平台移植。更多还原

【Abstract】 Digital TV overall shift in the current world has become an irresistible trend. To complete the simulation of the digital transition phase, digital TV set-top boxes are the consumers’first choice to gain digital audio-visual enjoyment. Hardware platforms become increasingly sound and mature, embedded software on the hardware platform do the main impact of products process. Designing a generic, portable embedded information processing systems becomes urgent.Current PC system information processing system through information management center distributes information to the application process. Process complete information management separately. This centralized management and decentralized processing system will become the trend in embedded Message Handling System. The establishment of two Message Processing Center Model based on ST real-time operating system achieves a modular, portable purpose. The first-class model pick up appropriate message to a screening information transmission queue through the system status and the message itself; second-class messaging queue distributes message to the correct responding module by current status of state machine. Focus message distribution mechanism is key technologies in this two-class state machine. Focus mechanism judge, filtrate and distribute information according to the state machine priority, the responding queue priority. Focus message distribution mechanism can filtrate redundancy and reduce system consumption. To speed up message handling system transplantation speed, Driver Interface Converter makes use of the middle layer to shield hardware-related details from the application layer. This simple, but comprehensive interface makes message handling layer information systems and real-time operating system relatively independent.Finally, system testing shows that the two-class information processing center model has modularized, independence, and generalized advantages to facilitate embedded digital TV set-top box software’s development and rapid the transplantation of cross-platform.更多还原