Research And Implement Of Embedded Audio System Based On ARM+Linux

Today, the design of embedded system has occupied a great field and been a great tendency of modern electronic design. As the important element to implement miniaturization, intelligence and knowledge innovation, embedded system has been widely used and plays an important role in national defense, traffic, energy sources, industry, communication and daily life. Many embedded audio systems have been applied into the CD, mobile phone, digital video and so on. But at present the embedded audio systems have not been deeply studied in China.This dissertation puts emphasis on researching and developing an embedded audio system which is based on AT91RM9200 microprocessor and embedded Linux operating system, and proposes an optimizing solution after deeply studied the design method of software and hardware of the whole system. In the aspect of the designing the hardware platform for audio system, firstly, the paper describes the structure and characteristics of the processor AT91RM9200, and then detailedly discusses the chips selection of hardware modules and designation of interface circuit. For implementing software platform, for one thing, the thesis presents the principle of the system start-up code, and detailedly describes the porting methed of the Bootlorder program U-Boot for AT91RM9200 platform after analyzes the U-Boot in detail. For another, based on the porting of Linux operating system and the designation of the JFFS2 root file system, the audio device driver with highly efficient buffer management algorithm has been implemented. The whole test of the audio system proves that the system is highly reliable and the function expected-recording processing and playing audio data- has been completed.Because the code to construct software platform and audio device driver has been developed in the way of modularization, the system can be easily ported to later similar audio products. The developing system discussed in this dissertation is more efficient than that without operating system. Because of the technique advantage based on the embedded system frame that I adopted, the audio system could be extended functions easily, and has a bright future.