Design And Implementation Of An Electronic Dictionary

With the advent of the information age and the rapid development of moderntechnology, PDA(Personal Digital Assistant), as a kind of consumer electronics, makespeople's life easier than before. As one of the PDA products, electronic dictionary promisesto help students with learning English and manage personal information effectively. It hasspacious foreground in applications and commercialvalue. This dissertation addresses someimportant problems of developing an electronic dictionary including software and hardwaredesign. After analyzing several algorithms of data compression, which is the key technologyused in the electronic dictionary, a new-improved algorithm is proposed. Firstly, the scheme of hardware design is presented after analyzing functionrequirements of the electronic dictionary. The hardware design includes the choice ofmicroprocessor, interrupt control and LCD driver control. The TOSHIBA'S T6B31 ischosen as the microprocessor. It is an 8-bit microprocessor of low power consumption andhigh performance that has been developed using CMOS silicon gate technology. T6B31 has8 types of interrupt sources. Processing interrupts have four special types, which are coldboot, time interrupt, key interrupt and ONKEY interrupt. The dissertation shows how todesign the LCD driver control circuit and the communications between the LCD driver andmicroprocessor. Secondly, the software design scheme of the electronic dictionary is proposed and thesoftware structure design is completed. According to the functions of the software system,the whole software system of the electronic dictionary is divided into many modules. Everymodule's function is pointed out and the relationship between them is discussed. Asimulation platform of the software environment is designed to make the programtransplantation easier. A method of establishing words warehouse is developed to meet theprophase objective. At the same time, the contents of the application layer are presented asan emphasis, and one special module is illustrated in detail. Finally, a new-improved algorithm is proposed after analyzing several algorithms oflossless compression, which are commonly used at the present. The repetition finder iscombined with the dynamic Huffman coding algorithm to yield a simple and efficientcompression method. It can find duplicate occurrences of strings without storing and parsingthe past sequence. The algorithm is proved to be accurate and effective by the results.