The Research And Design Of A CarPC Based On The USB Communication Bus

With more and more functions demanded for the electronics devices in private car, it is becoming a promising tendency that move the multimedia entertainment systems into the car, which integrates both the automotive industry and electronics industry, and could allow us not only to enjoy the convenience of a car as a transport tools, but also can have a comfortable driving, traveling environment. The current mainstream approach is using the specially structure of embedded system. Embedded system has many advantages such as low requirements for the embedded microprocessor, strong real-time function and high reliability. But the weakness is obvious also that the user can only enjoys the dedicate functions provided by system, usually very few, and with a lot of restricts if the user wants to add or modify the application of hardware and software capability according to their own needs as the general-purpose computer system.As an improvement of the carPC, this system is consisted of a general computer with general operating system (usually windows systems), and the corresponding peripherals. Because using a general-purpose computer system, much more relatively convenient if add peripherals, applications of software or hardware modifications, and the more importance is that the system has more features that the embedded systems don't meet, such as documentation and information processing, Internet and mobile communications and so on. There have been some products currently in the market. Which is usually reconstructed form a general computer motherboard, with large volume and high power consumption. While the others developed form the embedded system always with the disadvantages that weak processor and small display screen and so on.Based on the above analysis, this paper mainly focuses on the researching the CarPC design. Firstly, the concept of generous CarPC and the background of the CarPC and research significance are introduced. Next, present the basis theoretical for USB communication bus, focusing on USB bus topology, communication model, communication flow and transmission modes. Then present the new CarPC design which is based on the USB communication bus in contrast with the embedded system CarPC computer design, give the hardware designs and the hardware chips selection. At last not only provide the USB bus and USB device driver but also the micro-controller-side software designs and the usage of the development platform.