Improvement of USB Compatibility in an Embedded System

• Main Authors: Ping-Lin Wu, 吳柄霖
• Other Authors: Jin-Tai Yan
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/56449222383069069106

碩士 === 中華大學 === 資訊工程學系碩士在職專班 === 100 === With the rapid development of the electronic technologies in information industries, the consumer-oriented products with USB interfaces can be found in the majority of computer-related electronic products. It is well known that the presence of the USB interface makes electronic products to be easy to communicate with a computer. As a USB interface is supported for most of USB devices, the compatibility issues are further considered. Recently, there are about 30 pieces of USB hosts on computing market and the compatibility of these USB hosts is actually verified. However, these are serious compatibility issues for USB hosts in embedded systems. In order to solve the compatibility issues of the USB hosts in embedded systems, a USB host program is developed to solve the compatibility issues and some common USB device such as pen drive, card readers, external hard drives, the iPod, keyboard, mouse/mice, microphone, speaker and headset microphone are tested in our experiment. In this study, the USB hosts of the mass-storage devices, the human-interface devices, the audio devices and the composite devices are considered for the compatibility issue. Firstly, the available interface and the class information must be enumerated and analyzed. After the mass-storage device is enumerated, the USB host must also identify whether the file system is supported. In the enumeration process, the identified information to the PC through the UART transmits and displays its information. As the encounter in the types and the file systems is not supported, the designed USB host will not take any action to avoid the compatibility problem. In our experiment, the experimental results show that the average success probability for the compatibility between the USB host and USB device is 96%. For the mass-storage devices, the human-interface devices, the audio devices and the composite devices, there is significant improvement for the compatibility issues in the embedded systems.