The Design Of Car MP3 Player System

With the rapid development of digital information technology and network technology, the automatization ,also the intelligentization and internetization of car are brought forward in the calendar. The car player system as a necessary part of car has to face the technical innovation. According to the design request and the characteristic of car player, a scheme of car mp3 player is brought forward. This system consists mostly of USB Host System part, mp3 files decoder and RF output part.In the design of the Embedded USB Host System, we analyze the basic characteristic of the USB System first. The USB System's architecture, data communication model, data packet format and the USB standard descriptor are analyzed especially. On the basis of analyzing the USB device Mass Storage Class specification, the logical communication model between the host and device is established. Whereafter we build the hardware and software of the USB Host System, then we test them carefully. The USB bus driver is realized, which can detect, recognize and set up the USB device, then the Bulk-Only transport driver is builded base on USB Mass Storage Class Specification. Based on Bulk-Only transporting and sending the Mass Storage SubClass Command to the devices, we build the FAT system's interface by which the USB host can read and write the files in the Flash and Portable Hard Disk.In this paper, we use mp3 decoder chip to realize the mp3 player function. Audio frequency signal exported from the chip can be sent to the RF chip, then the signal will be received by the radio at a certain controllable frequency. It is no need for us to change the electric design of the car, and we can use this system in any car. At last, in our design we use the embedded real time operating system uC/OS-II as the software project base, so we can highly improve both the efficiency and the real-time and stable characteristic of the system. Based on the processes mentioned above accomplished, we can realize the system's preconcerted play function successfully.