32位ARM嵌入式系统扩展USB接口设计

基于 ARM 处理器的32 位嵌入系统具有极高速和大容量的数据处理能力，如何设计ARM 与主机设备或系统的通信接口、提升数据通信能力，成为嵌入式系统设计的一大问题。文章给出了一种USB 接口方案，对比RS-232 串行口，大大提高了嵌入式系统的数据吞吐能力，与以太网接口相比有即插即用特性、有块和同步等多种数据传输模式，更适合音视频码流传送。文章具体阐述了方案的硬件、软件设计，并应用于音频PCM 码流传送，实验结果显示音效流畅，方案有较高参考价值。
关键词：ARM ；嵌入式系统；USB；音频PCM 码流；
Abstract：The processing speed and capability of 32bit embeded system based on ARM
procesor is very high and powerful, how to design the communication interface between ARM processor and host or other system, and how to enhance the capacity of communication,becomes a question of embeded system design. This article brings out a design of USB interface for ARM embeded system, compared with the RS-232 serial port, USB port increases the data thruput of ARM embeded system greatly, compared with the ethernet port, USB port has PnP characteristic , and has bulk transfers , isochronous transfers and other data flow types, it is more suitable for audio and vedio data flow transferring. This article discuss the hardware and software implementation detailly, and applies USB port to audio PCM stream transferring, the result show that the voice is very mellifluent, so this design is worthful to refer.
Key words：ARM, Embeded System, USB, Audio PCM stream.