Research And Implementation Of A Real-time Embedded Graphics System Based On Asynchronous Communication Control Strategy

In the history of computer development, graphics system has been occupied anextremely important position. Traditional embedded graphics system has a simplegraphical interface, small resources-occupied and other characteristics, but with therapid development of embedded system, it can’t meet the needs of application.ERTOS(Embedded Real-Time Operating System) has the advantages of goodreal-time, high stability and other features. It is widely applied in high-tech fieldswhich have stringent requirements of the system response time; it is also one of themain development directions of embedded application in the future. At present, thestudy of embedded graphics system oriented to ERTOS is increasingly becoming ahotspot.The graphics system based on C/S structure has the advantage of flexiblestructure and good extension, but need a communication control strategy to ensure theinteraction between the server and the client. As the increasingly diversified therequirement of the graphics abilities for the embedded application, the C/S structuresystem has become a very important trend in embedded graphics system development.For all this, this paper designs and realizes RTGDS which is a real-time embeddedgraphics system based on asynchronous communication control strategy. It’s mainworks in the follow areas:First of all, This paper design the overall architecture of RTGDS system. Thisarchitecture draw lessons from X Window’s C/S structure, aim at the features of theERTOS, and make full use of hierarchical and modular design method, which makeRTGDS architecture has good portability and scalability.Second, in accordance with the characteristic of more interaction between theserver and the client in RTGDS system, two asynchronous communication mechanismmodels are constructed: asynchronous callback mechanism model and thepublish/subscribe model based on event. Asynchronous callback mechanism model ismainly used to handle request/reply relationship between the server and the client,and in this model also include a request/reply processing mechanism, to handledifferent types of requests in RTGDS system. Publish/subscribe model is built forevent-driven mechanism, and designs a complete set of event routing rules, to ensurethat the system can accurately distributes events to window.Finally, it designs and implements the RTGDS system. This paper presents a novel window-tree to represent the complicated relationship between each window.And according to the characteristics of driver in ERTOS, using methods ofhierarchical, designs a driver layer that ease of portability. At last, this paper designsthe test plan and constructs an experimental platform. Meanwhile, test and analysis ofeach performance index of RTGDS system in detail.