Study And Realization On BREW Technique In The Embedded System Development

With the development of the technology of wireless communication and the technology of embedded software and hardware, the system of cell phone has been growing up from a personal communication terminal to a huge system integrating all kinds of additional functions. However, with the accumulation of software productions and the complication of the architectures, the task of developing a cell phone system has been more and more difficult. The disadvantages of traditional developing method have been on the stage, such as the high level of coupling, the difficulty of maintaining and updating and the high dependency on the hardware system.In order to solve such kind of situation, the corporation of Qualcomm(?) has brought forward the BREW architecture, which provided a virtual and standard execution environment to ensure the application's ability of being transplanted and hardware independency.This paper implemented the camera controlling block of the BREW architecture mentioned above. The content is discussed by focusing on the mechanism of the implementation of camera's functions and the interactions between which and the BREW applications above it and the native functions supporting it.From the aspect of the entire system of the cell phone, the system being discussed is a middle layer locating between BREW applications and the hardware related modules, which transforms the hardware related implementation to the standard hardware independent implementation.From the aspect of the interactions between BREW applications and the system being discussed, the system is a native functional module which implements the functions of Original Equipment Manufacture (OEM), hiding the actual implementing mechanism of the cell phone system, encapsulating the hardware implementation, operation system and all the other software modules. Meanwhile, the system realized the mechanism of developing with a procedure-oriented language (the C language) to realize the object-oriented method and the mechanism of protecting memory access in runtime.From the aspect of the system itself, as the middle layer which realizing the camera functions, it encapsulated the hardware related digital image type from the supporting layer. The system processes and transforms the different digital image data from the supportinglayer with digital image processing techniques to adapt to the standard BREW architecture.And from the aspect of the interactions between the system and the native hardware related modules, the system is built on the native hardware realizations. Integrating with all the other native software modules, the system realized the concurrency controlling, communication and resource competition of tasks based on an embedded real-time operation system(RTOS), assuring the stability of the system.It has a applicable importance in the wireless communication field to research and implement the mechanism of realizing the object-oriented designing with procedure language, the memory protection in runtime, the digital image processing algorithms used in the function of camera and the communication and resource competition between tasks in the embedded RTOS system. This paper has been doing effective study and implementation in these aspects in order to contribute to the development of this field.