A Research And Construction Of Handheld Devices Based On Arm And Linux Dedicated Embedded

As the rapid progress of computing technology and communication technology in recent years, many embedded products especially consumer electronics have achieved great success in marketplace. From the standpoint of application, this paper tries to discuss the following issues:optimization of system platform, development of application software, development of utility software. It starts with studying the problems needed to be solved in the process of designing a dedicated embedded handheld device, which we take the "Portable Drug Addiction Rapid Pupil Detector" as a study case. If these problems are solved properly, the performance of the embedded device could be improved, and the applications could be broadened.This paper chooses Linux to be the operating system of the dedicated embedded handheld device. As the core of an operating system, Linux supports a variety of CPUs with different architectures. It is robust and reliable, and highly configurable and reducible. But optimization to Linux is always necessary on a dedicated embedded handheld device. This paper tries to optimize a Linux system to improve its boot up time. It introduces a technique to measure the kernel boot up time, and with a use case to study why a standard kernel boots slowly. Then some efforts are made to improve boot loader, Linux kernel, and file system to speed up boot up time of the system. The boot up time is reduced significantly on an optimized system.Development of embedded GUI software in embedded systems becomes a trend, due to the increasing in complexity and functionality of embedded systems. While the special hardware environment of the embedded system determents that embedded GUI applications is different from desktop GUI applications. This paper introduces several popular GUI systems in Linux. Then it compares two system software architectures in Linux. And it takes the design of the GUI software of "Portable Drug Addiction Rapid Pupil Detector" for example, to show how to design a GUI application to use with touch screen. The paper describes the design of an embedded Chinese pinyin input method which uses a software keypad as an input device. The input method is based on Qt/Embedded on embedded devices running Linux.