基于嵌入式Linux的多功能移动终端研究与实现

发布时间：2018-12-11 20:06

【摘要】：随着嵌入式技术与移动通信技术的迅速发展,基于嵌入式多功能的图形化移动终端成为一个热点研究领域。尤其在互联网技术的推动下,传统实体渠道因营业前台服务压力大、服务效率低,难以满足客户的实时服务需求,而电子渠道通过将产品的销售与服务数字化,实现供应商和客户之间的直接交易,符合市场发展的需求。因此,开发一款既具备账单打印、磁条卡刷卡和非接触式刷卡等电子消费功能,又具备语音、空中充值、售卡等运营业务办理功能的电子渠道智能终端显得很有必要。本文通过对多功能移动终端的功能需求进行分析,提出了终端硬件和软件的总体设计方案,并从硬件和软件两个方面研究具体的实现过程。硬件方面：以处理器硬件资源能否满足功能需求为前提,完成芯片选型和外围关键模块的电路设计；软件方面：移植Linux内核,搭建系统开发环境。最后重点研究了在嵌入式Linux平台下基于帧缓冲的LCD驱动开发和系统软件低功耗的实现,并提出了一套符合嵌入式系统软件低功耗管理的方案。本文的主要工作包括以下几个方面： 1.首先,选择ARM9E系列处理器S3C2416为主CPU,选取Linux为嵌入操作系统,依据功能需求设计软硬件总体方案。然后设计外围关键模块电路,如LCD模块、磁条卡模块、IC卡模块、NFC模块、USB扩展模块。 2.基于硬件平台,搭建开发环境。包括以下几部分：a.建立交叉编译开发环境。b.修改U-Boot源码并移植到硬件平台。c.分析Linux内核源码,实现内核的裁剪、编译与移植；d.根文件系统(选取YAFFS)的创建。此外,为了满足系统应用程序支持用户图形界面开发和嵌入式数据库开发的需求,移植Qt/Embedded、SQLite。 3.介绍了在嵌入式Linux系统下设备驱动程序的开发流程,实现对外围设备驱动程序的开发。本文着重研究在嵌入式Linux内核下的帧缓冲驱动与LCD设备驱动的工作原理,开发基于帧缓冲的LCD设备驱动程序,并编写LCD应用程序,通过直接显示位图和显示Qt高级图形界面这两种方法来检验LCD驱动程序的可行性和稳定性。 4.本文重点研究了嵌入式系统软件低功耗的设计。利用Linux的调度机制和APM电源管理技术,通过修改u-boot制作虚拟BIOS以支持APM电源管理,结合处理器的节能模式设计系统工作状态,并通过利用Linux的固有数据结构与函数,在应用层采用阈值预测和TimeOut技术相结合的策略,实现了系统工作状态的智能转换,同时,为了进一步的优化功耗管理,在设备驱动层针对特定的外围设备建立设备功耗管理表与队列的索引机制,实现特定设备的主动休眠,最终使系统休眠功耗仅占系统运行功耗的12.63%,达到了设计要求。
[Abstract]:With the rapid development of embedded technology and mobile communication technology, the graphical mobile terminal based on embedded multi-function has become a hot research field. Especially under the promotion of Internet technology, the traditional physical channel is difficult to meet the real-time service demand of customers because of the pressure of the business foreground service and the low efficiency of the service, and the electronic channel digitizes the sales and service of the products. Achieve direct transactions between suppliers and customers, in line with the needs of market development. Therefore, it is necessary to develop an electronic channel intelligent terminal which not only has the functions of bill printing, magnetic stripe card swipe card and non-contact swipe card, but also has the functions of voice, air charging, selling card and so on. By analyzing the functional requirements of multi-function mobile terminals, this paper puts forward the overall design scheme of the hardware and software of the terminal, and studies the implementation process from the two aspects of hardware and software. Hardware: on the premise of whether the processor hardware resources can meet the functional requirements, complete the chip selection and peripheral key module circuit design; Software: transplant the Linux kernel, build the system development environment. Finally, the development of LCD driver based on frame buffer and the realization of low power consumption of system software under embedded Linux platform are studied, and a set of low power management scheme for embedded system software is proposed. The main work of this paper includes the following aspects: 1. Firstly, ARM9E series processor S3C2416 is selected as the main CPU, Linux is selected as embedded operating system, and the overall scheme of software and hardware is designed according to the functional requirements. Then design the peripheral key module circuit, such as LCD module, magnetic strip card module, IC card module, NFC module, USB extension module. 2. Build the development environment based on hardware platform. It includes the following parts: a. Build a cross-compiler development environment. Modified U-Boot source code and ported to the hardware platform. C. Analysis of the Linux kernel source code, to achieve kernel clipping, compilation and transplantation; d. The creation of the root file system (select YAFFS). In addition, in order to meet the needs of system applications supporting user graphical interface development and embedded database development, Qt/Embedded,SQLite. is transplanted. 3. This paper introduces the development process of device driver in embedded Linux system and realizes the development of peripheral device driver. This paper focuses on the working principle of frame buffer driver and LCD device driver based on embedded Linux kernel, develops LCD device driver based on frame buffer, and writes LCD application program. The feasibility and stability of LCD driver are verified by direct display of bitmap and display of Qt advanced graphical interface. 4. This paper focuses on the design of low-power embedded system software. Using the scheduling mechanism of Linux and APM power management technology, virtual BIOS is made by modifying u-boot to support APM power management, and the working state of the system is designed in combination with the energy saving mode of the processor, and the inherent data structure and function of Linux are used. In the application layer, the strategy of combining threshold prediction and TimeOut technology is adopted to realize the intelligent transformation of the system working state. At the same time, in order to further optimize the power management, In the device driver layer, the index mechanism of device power management table and queue is set up for a specific peripheral device to realize active hibernation of a particular device. Finally, the system sleep power consumption accounts for only 12.63 of the running power consumption of the system, which meets the design requirements.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP368.1

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