Research On LCD Testing System Based On Embedded ARM9

The original testing instruments can not satisfy new product's requirement because new LCD is big size,colour,multi-testing-parameter and lattice array. The testing instrument of new generation must be developed because the old testing equipment can only test either electronic or optic parameter, and its speed is slow and precision is rough,even some paraments can be not tested.The rapid development of the semiconductor technology is providing hardware condition for LCD testing system being developed. New 32-bit embedded CPU has controlled main markets with its high performance, low power and cost, and it has taked possession of application space occupied by 8-bit MCU with its price being falling and its development environment being mature since it has come forth.The new testing instrument with ARM technology not only has a lot of advantage like low cost,fast development speed and real-time tracking testing, but solves much bottle-neck questions as well, such as lower speed.The project is discussed, which placees emphasis on the selection of CPU, the design of total structure, and hardware and software system. This thesis focuses on building up a testing platform with open architecture on hardware and software. Its purpose is to provide an environment for application software and a reliable testing tool for testing LCD/LCM.Through analyzing the requirememt of LCD testing instrument, the total structure model and every function of LCD testing system are determined, the hardware parts are in detail designed, including MPU and its peripheral circuit, the circuit of LCD/LCM testing signal is produced, and the circuit of LCD/LCM optic signal is sampled. It is important and difficulty for small current of LCD/LCM to test. The precision of small current rises greatly by adding denoising circuit in dealing with small current circuit. According to testing feature of electronic and optic parameters, sampling optic part is separated from main equipment and connected to main CPU by USB interface. The method is not only flexible, but also convenient, and it solves incorporate question about testing electronic and optic parameters. The testing instrument tests not only electronic but optic parameter as well. The denoising circuit and method are designed by analyzing source of noise, which improves the system performance of testing equipment.In the design of operating system,we analyze the mechanism of RT-Linux and the program model and real-time character of embedded LCD testing system. Besides, the multitask dividing model as well as rational scheduling strategy of LCD testing system is presented, and the basic structure of real-time application framework is constructed.