基于ARM的移动高清连接反向控制传输的设计与研究

发布时间：2018-08-21 07:08

【摘要】：移动高清连接接口(Mobile High-Definition Link, MHL)是一个可以将智能手机、移动视频播放器、摄像机以及其他移动设备连接到高清电视、投影机、显示器以及其他显示设备的音视频接口。该接口先将高清晰度多媒体接口(High Definition Multimedia Interface, HDMI)或数字视频接口(Digital Visual Interface, DVI)中的三对最小化传输差分信号(Transition Minimized Differential Signal, TMDS)做三倍速度调制,然后复用目前大多数移动设备已经拥有的micro-USB接口,将移动设备中的影音图像传送至大屏幕的显示设备上显示,从而提高人们共享信息的能力。与传统音视频接口相比,MHL接口具有连接管脚少、传输速度快等优点。但由于MHL技术发展时间短,很多技术方案尚不成熟,目前只能让移动设备中的影音图像传输到显示设备,还不能从显示设备端对移动设备进行反向控制。针对以上问题,本文将设计和研究一个反向控制传输系统,该系统包含一个MHL接口,一个HDMI接口以及一个人机交互接口。系统的核心处理器解析来自人机交互接口的信息,再将解析完的信息转换成MHL协议规范的格式,然后按照MHL协议规范通过MHL控制总线将其发送到智能手机。智能手机接收到反向控制传输系统的命令和数据后作出相应变化,并通过MHL的数据总线将变化后的影音图像传输到显示设备,从而实现反向控制传输。设计和研究的MHL反向控制传输系统包含硬件和软件两部分。硬件部分以ARM为控制核心,包含一个人机交互接口和一个电源管理单元。人机交互接口采用人们日常办公所用的键鼠系统,用于信息输入,它包含有线和无线两个方面,有线使用USB接口解决方案,无线采用蓝牙技术实现。电源管理单元主要负责对智能手机进行智能充电以及对整个系统进行功耗管理。软件部分构建在Linux操作系统上,分为底层设备驱动和上层应用软件两方面。底层驱动直接操作硬件,负责为上层应用提供软件接口,屏蔽硬件的实现细节；上层应用负责协议的解析和转换以及电源管理策略的实现,它将从底层驱动接收到的数据进行处理后再发送给底层驱动。底层驱动分模块挂载到Linux上,Linux根据上层应用的信息在适当的情况调度底层驱动。最后对该反向控制传输系统进行测试,测试结果表明：当智能手机接入该系统时,系统正常工作并对手机进行充电,若此时智能手机处于视频播放状态,通过键鼠系统的控制可使其处于停止、播放、快进、快退等状态；当智能手机与反向控制传输系统的连接断开时,系统处于低功耗状态。
[Abstract]:Mobile HD Connect Interface (Mobile High-Definition Link, MHL) is an audio and video interface that connects smartphones, mobile video players, cameras and other mobile devices to high-definition televisions, projectors, monitors, and other display devices. The interface first modulates three pairs of minimized differential signal (Transition Minimized Differential Signal, TMDS) in (High Definition Multimedia Interface, HDMI) or (Digital Visual Interface, DVI), which is a high definition multimedia interface. Then we reuse the micro-USB interface that most mobile devices already have, and transfer the audio and video images from the mobile devices to the display devices with large screens, so as to improve the ability of people to share information. Compared with the traditional audio and video interface, the MHL interface has the advantages of less connection pin and faster transmission speed. However, due to the short development time of MHL technology and the immature of many technical schemes, it can only transfer the video and audio images from the mobile device to the display device at present, and can not reverse control the mobile device from the display device. In view of the above problems, this paper will design and study a reverse control transmission system, which includes a MHL interface, a HDMI interface and a human-computer interface. The core processor of the system parses the information from the man-machine interface, then converts the information to the format of the MHL protocol specification, then sends it to the smartphone via the MHL control bus according to the MHL protocol specification. After receiving the command and data of the reverse control transmission system, the smart phone makes corresponding changes, and transmits the changed video and audio image to the display device through the data bus of MHL, so as to realize the reverse control transmission. The design and research of MHL reverse control transmission system includes two parts: hardware and software. The hardware part takes ARM as the control core, including a man-machine interface and a power management unit. The man-machine interface uses the mouse and keyboard system used in people's daily office, which is used for information input. It includes wired and wireless. Cable uses USB interface solution, and wireless is realized by Bluetooth technology. The power management unit is mainly responsible for smart phone charging and power management for the whole system. The software is built on the Linux operating system and is divided into the bottom device driver and the upper application software. The bottom driver directly operates the hardware, is responsible for providing the software interface for the upper application, shields the hardware implementation details, and the upper application is responsible for the protocol analysis and conversion, and the implementation of the power management strategy. It processes the data received from the underlying driver and sends it to the underlying driver. The underlying driver module is mounted on the Linux to schedule the underlying driver according to the information of the upper application. Finally, the reverse control transmission system is tested. The test results show that when the smartphone is connected to the system, the system works normally and charges the mobile phone, if the smartphone is in the state of video playing, Through the control of mouse and keyboard system, it can be in the state of stop, play, fast forward, fast back, etc. When the connection between the smart phone and the reverse control transmission system is disconnected, the system is in the state of low power consumption.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP334.7

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