Design Of In-vehicle Multimedia Information System

With rapid development of vehicle industry and requirement of in-vehicle applications, the central control system should have multimedia process ability. Thus how to establish a system including electronic equipment monitoring and entertainment functioning has become a question for discussion, which has also grown up a domain such as vehicle carrier MP3, automobile GPS navigation system, CAR-DVD etc. This paper was aroused at this background and mainly focused on research and establish a system have the ability to provide driver human machine interface, which could display vehicle electronic equipment info and playback sound and video. ARM core based CPU was used as the main control unit of this system to link different equipments through CAN bus. This system had a CAN bus interface which could connect CANOpen slave devices. Only sub profile was required when a certain slave device connected such as DS-301, therefore the driver could control and monitor such equipment conveniently.This paper discussed the research background of this subject and structure of in-vehicle multimedia information system and given out the general frame of hardware and software. In hardware design, special protect circuit was added to ensure main interface work well, for instance universal serial bus ESD protect circuit and power EMI filter. In software design, open-source embedded Linux version 2.6.13 was used as operation system. Two methods of driver loading technology were compared in detail, listed advantage of dynamic driver loading in debugging. Programming skill of application running on MiniGUI and main flow of camera capture, sound and video player were given.At last, by research, compare and design, we mainly completed establishing in-vehicle multimedia information system, below hardware circuit was completed: S3C2440 core circuit, MCP2515 chip based CAN2.0B bus interface circuit, liquid crystal display with 640×480 pixel resolution driver circuit, universal serial bus ESD protect circuit, inter-IC sound card circuit; Software system was based on open sourced embedded Linux with 2.6.13 version. Below device drivers were customized: inter-IC sound bus UDA1341 sound card driver, ZC301P core based universal serial bus driver, LCD framebuffer driver, CAN bus driver through serial peripheral interface. Based on these linux device drivers and graphic user interface MiniGUI, below applications of different application background were completed: sound player which support MP3,WMA,AC3,WAV file playback based on madplayer, dynamic camera capture and display, CAN interface electronic simulated meter. This paper designed a system had not only ability of multimedia file playback but CANOpen protocol device support. CANOpen services were running in the background in embedded linux as a user-defined service named MiniCAN, which could connect a CANOpen minimal capacity slave device. Such device was described by CiA(CAN in Automation) means testing capacity and compatibility of CANOpen master. Additionally, the system provided adequate application interface for further develop. By using the open-source linux, the opening and configurable of software system was the most advantage of this in-vehicle multimedia system.