| Because WiFi is a free band without need of any telecom operator license around the world, so WLAN wireless devices provide a worldwide wireless air interface whose cost is extremely low and data bandwidth is very high. WiFi users can quickly browse the web within the coverage area and answer the call anytime. And other WLAN-based broadband data applications, such as streaming media, online games and other functions are subject to the industry's attention. With functions of WiFi, users can make long-distance call, browse the Web, send and receive e-mail, download music, transmit digital photos and so on with no worries about the slow pace and high cost problems. Under such a background, WiFi applications are being used in increasing numbers on handheld devices, while the smart phone is one of them. Different from the Bluetooth technology which was used on the phone earlier, WiFi has greater coverage and higher transmission rates, so WiFi mobile phone has become the current fashion trend in telecom industry.In this paper, on the basis of the research and development of the embedded handheld device, we integrate the WiFi functions to the terminal, so that the terminal not only has basic function such as phone call, audio and video, but also can access wireless network. The hardware platform is built on SH7343,which is produced by Renesas from Japan and we chose 88W8686 as WiFi module, these two chips can meet our requirement. T-Kernel OS is applied to our handheld device. It is open source, free and widely use in the Japanese market.Main thesis is divided into four parts, the first is a brief introduction of WiFi technology and embedded systems, the technical characteristics of WiFi and several popular embedded operating systems in the market currently are introduced and compared.In the second part,It mainly discuss the system's overall hardware design as well as the WiFi function module circuit design based on SH7343.The third section details steps to set up the software development platform and cross-compiling environment. It also describes how to design WiFi driver based on the software development platform just mentioned.The last part describes the whole process of functional test of the WiFi module,given the analysis of test results.The results show that the realization of the WiFi function of the handheld device can satisfy our requirements, hardware and WiFi function works stable and reliable. In addition, the strength and power of the wireless signal can meet the requirements of the radio waves act. The successful implementation of the WiFi function brings more features to the handheld device and makes it easier for users to access the mobile Internet and share data. |
