文档介绍：嵌入式终端中MP3功能
的研究与实现
摘要
随着现代通信技术的发展,数字声音作为一种存储、处理和传输高保真声音的方法,在消费电子、通讯等众多领域已得到广泛应用,与之相关的数字音频压缩技术也得到了充分的发展,在数字音频压缩技术中MP3(Moving Picture Experts Group,Audio Layer 3)以其优异的性能而得到广泛的应用。与此同时,以手机、PDA为代表的嵌入式终端类产品的普及率也越来越高,本文的主要目标是研究如何在此类产品中实现MP3,以丰富产品的功能。
在嵌入式终端中实现MP3主要有两种方法:软件解码方式和硬件解码方式,软件解码方式要求处理器的处理能力较强,一般应用于高档产品中,硬件解码方式对处理器要求不高,但需要专门的硬件解码芯片的支持。本文主要研究在以Motorola公司的MC68VZ328为核心处理器的嵌入式终端中实现MP3功能,在深入研究了各种嵌入式终端中MP3的实现方法,并比较其优缺点和实用范围后,选择了使用硬件解码方式在目标系统中实现MP3功能。硬件解码芯片采用Atmel公司的基于51内核的SOC芯片AT89C51SND1C,在此芯片的基础上构成一MP3模块,MP3模块采用MMC卡来存储MP3文件,并通过USB和桌面PC机进行文件的同步。目标系统通过UART串口来控制MP3模块的运行,并通过Xmodem协议实现两部分间的文件传输。
系统的实现包括两个部分:硬件电路和软件系统,重点在软件系统部分,主要包括调试环境的建立、MP3解码的实现、MMC卡存储系统和USB系统。
关键词:MP3,嵌入式终端,AT89C51SND1C,MC68VZ328
Abstract
Along with the development of munication technology, digital audio is used as a method to store, process and transmit high fidelity sound, which is widely used in many fields like public electronic products, munication etc. and the associated digital pression technologies are also highly developed. MP3 is the most popular one in various digital pression technologies according it’s excellent nature. At the same time, embedded terminal products like mobile phone, PDA are wildly spread in public, the main ideal in this master’s thesis is to study how to implement MP3 feature in embedded terminal products.
There are mainly two methods to implement MP3 feature in embedded terminal: software decoding and hardware decoding, software decoding method mainly used in top grade product, because it’s need a powerful processor, hardware decoding do not care the processing capacity of main processor, but it’s need a dedicated chip to process audio pression. This paper mainly do research in implementation MP3 feature in target system ,which is based on Motorola MC68VZ328 processor, after studying paring different methods of implementation MP3 feature in embedded terminal, we choose hardware decoding method to implement MP3 feature in target system, the hardware decoding c