Reaserch And Implementation Of Embemed Audio System Based On S3C2440

In recent years,the embedded system develops with the peple's requirement.the intelligence equipment taking that soft hardware is composed of as notable characteristic,taking that the consumption electron produet as leading faetor reaehes hitherto,development with the speed that extra people imagines. The embedded system is a specific computer system that focuses on the application on the base of computer technology including both software and hardware,and is qualified with the rigid requirement of application system about function,reliability,cost,size and power consumption.With the development of network technologies,the performance of IP networks gets great improvement.At the same time,compression technologies make the data size of multimedia much smaller.As a result,real time transmissions of audio multimedia over networks can be realized.As more and more traditional radio stations use computer networks as media of broadcasting,the device that can receive audio media from radio stations over networks as the traditional radio receiver does is needed.With the development of embedded technologies,embedded systems that can receive media information from remote radio stations over networks become possible.Compared with the streaming server based on PC,the embedded streaming server has the advantagesof small volume,portability,high funational speeialization,low-cost,steady-going and real-time.So it is becoming more and more popular with development manufacturers and consumers .In such background,this paper studies the realization principle of streaming media teehnology,upon which a streaming server based on an Embeded platform based on ARM processor. According to performance and characteristic of the Internet Radio,the hardware and software designing case are brought out,including the realizing principle.Based on the characteristics of S3C2440,a system for MP3palyer and ethenet radio is received ,by using ARM processor and some outer module as hardware platform, and using embedded Linux as operationsystem, and using Mplayer as ethernet broadcast software. In order to support a smooth process of data ,we added the madlib and live protocols to source software–Mplayer.In this article,we analyze this embedded multimedia system from three levels: Hardware,system software,application software.Firstly,a comprehensive desecription about the significance of the reseach work is givne.The current research stuats of multimediaplayer embedded system,embedded Linux and stream media teehnology are also deseribed.Secondly, the hardware system design is discussed. The system takes the SamsungS3C2440 Proeessor which based on ARM architecture as the main control unit,takes Philips UDA1341 as the audio coder–deeoder processing unit .Being added external memory and keyboard,the system realizes to transmit control signal and audio data by IIS bus.Thirdly, The study of this paper places emphasis on the available software of syetem and the dissertation design of a real time transmission client of audio multimedia based on embedded Linux operating system. The system software part includes bootloader vivi porting of Linux kemel,Yaffs root file system and Linux deviee drivers .In the software development part,we discuss Linux application program。In order to play as Embeded system Radio,the Mplayer is ported on development board. A new audio decoding algorithm in which the traditional float- point algorithm is replaced by the fix- point algorithm for the MP3 format is used in the embedded system.Aimed at the limitation of ARM resources , this dissertation discussed an optimized designed of MP3 decoding.At last,the dissertation also presents further work in funture. With drivers ported in Linux kernel and application programe loaded into filesystem sueeessfully,the whole design is fnished.Following the testing: bit rate upto 128Kbps,delay time less than 15s,the performance of this syetem is good. It will have wide foreground of market apply.