The Research And Implementation Of Multi-functiona Mobile Terminal Based On Embedded Linux

With the rapid development of embedded technology and mobile communication technology, multi-functional mobile terminal with graphical interface based on embedded becomes a hot research field. Especially in the development of the Internet technology, traditional physical channels for business with large service pressure on business hall front desk and low service efficiency, it is difficult to meet real-time customer service, but electronic channels can trade directly between the supplier and the customer through digitizing the products sales and services, which meet the need of the market development. Therefore, developing an electronic channels intelligent terminal which has the function with electronic consumption such as bill printing, magnetic stripe card swiping, contactless IC card swiping and so on, but also with the operator service handling such as speech, air recharge, selling cards and so on is very necessary.A design overall scheme of the terminal for hardware and software is put forward through the analysis for the demands of the multi-function mobile terminals in this paper, this paper focus on a specific design form the hardware and software aspects. From the aspects of hardware:it completes chip selection which depend on the processor hardware resources can meet the functional requirements, and completes the circuit design of peripheral key modules; From the aspects of software:it includes porting Linux kernel and setting up development environment. Finally, it focuses on the development of LCD driver based on frame buffer and the implement of system software design for low power, and it puts forward a set of software low power management scheme that adapt to embedded Linux system at last.The main work of this paper includes the following aspects:1. First of all, it chooses S3C2416that belongs to ARM9E series processor as CPU, chooses Linux as the embedded operating system, and designs overall scheme of hardware and software according to the function demand. Then it designs the circuit of peripheral key module, such as LCD module, magnetic stripe card module, IC card module, NFC module, USB extension module etc.2. It sets up development environment based on the hardware platform. It includes following parts:(a) Building cross compiler development environment,(b) Modifying the U-Boot source code and porting to the hardware platform.(c) Doing kernel cutting, compiling and porting through analysis the Linux kernel source code.(d) Creating root file system (YAFFS). In addition, in order to meet the development needs of system application that support graphical user interface development and embedded database development, Qt/Embedded and SQLite have been ported.3. This paper introduces the development process of device driver in the embedded Linux system and develops the peripheral equipment driver. This paper focuses on the principle of embedded Linux kernel framebuffer driver and LCD device driver and develops the LCD device drive based on the framebuffer, then writs LCD applications to test the feasibility and stability of LCD driver by displaying bitmap directly and displaying Qt advance graphical interface.4. This paper focuses on the software design of low-power in the embedded system. Taking advantage of the Linux scheduling mechanism, adopting mature APM power management technology, supporting APM power management by modifying the u-boot source code and designing system working state combined with the processor’s energy-saving model, using the nature data structure and the function of Linux, and using the strategy of the threshold prediction combined with TimeOut algorithm at the application layer, all that make the intelligent conversion of system working state comes true. At the same time, in order to further optimize the power consumption management, it established an index mechanism through conmbined device power consumption management table with queue in device driver layer for special peripheral device and realised the initiative sleep by special device. At last, when the system works on the sleep state, it only consumes12.63%of the total power, meeting the design requirements.