Research On The Fault Test Method Of Digital Circuit With Microprocessor

As the development of electronic technology, electronic devices turn to increasingly smart. The key of intelligent circuit is a microprocessor circuit used. It is a problem for intelligent electronic equipment producing and repairing to the test and fault diagnosis of digital circuit with microprocessor. Therefore, research on fault testing microprocessor circuit and establishment effective testing methods become very meaningful.In this paper, the important part of the equipment in the intelligent(microprocessor circuit) as the research object, starting from the characteristics and test requirements of microprocessor-based circuit, systematically studying the problems of design what are respectively testing system with microprocessor, main fault types of circuit and the test algorithm.The main work and achievements of this dissertation are as follows:(1)This thesis presents the design scheme of testing system of a digital circuit. Meanwhile, the article discussed the function of composition in this system, the main performance index, working principle and the function of each part.(2)Aiming at the characteristics of bus structure with microprocessor circuit,however, it is difficult problem for testing and positioning to using conventional instruments for testing bus circuit. Then, this paper proposed the bus test and fault diagnosis method based on JTAG circuit. And the test results show that this method has the characteristics of simple circuit and testing speed.(3)Contraposed the problem of which this microprocessor circuit has large capacity storage device, this paper mainly studies on the problem of testing and diagnosing to the memory such as ROM, RAM and so on. Researching content mainly includes the fault type of the memory, the test algorithm of read-only memory and random memory and the use of simulation technology to realize the circuit of testing ROM, RAM, and carrying on the research of the preliminary experiment.(4)Aiming at the fact which the current very large scale integrated circuit and memory are built-in self test technology, the paper studies the test principle and test method in self-built.