Hardware Design For Circuit Fault Diagnosis System Based On JTAG Interface

The present era is called "Information Age", the rapid development of informationscience and technology has become an important content of the modern society,information science and technology is penetrating into all aspects of social life andplaying an increasing important role. As one major component of the informationtechnology, Test&Measurement involves all aspects of information technology.With the rapid development of microelectronics technology and widely use of theelectronic components packaged by high-density pin surface mount, the traditionaltesting methods not only increase the test cost (including the test expense and test time)but also become more and more difficult in using to the various test scenario. Thanks tothe boundary-scan tests standard IEEE1149.1protocol, this problem can be greatlyrelieved. The core idea of the boundary scan is that the virtual probes are established forthe additional circuit chip pin, via these virtual probes, integrated digit circuits can thenbe tested automatically due to the support of the components such as CPLD, FPGA andDSP on the board under test. This paper proposes and develops a digit circuit testing&fault diagnosis system based on the boundary-scan test technology, thus provides a veryconvenient and effective development tool for testing of digital circuit.This thesis consists of a software portion about PC computer and a hardware partabout JTAG test controller. After studying of the theory of testability, fault diagnosisalgorithm, IEEE1149.1protocol contents and the BSDL file, the author designs asystem which function is to achieve functional test, pin states acquiring, andinterconnection test, test result displaying and locate fault through the PC software. Themain work of this thesis is the development of the boundary-scan test controller, whichprovides test clock, gets the test data from the host computer, analyzes and process thedata, determines the type of test, finishes the storage and processing of data. The testcontroller connects upper computer through the USB cable, and achieves USBtransmission with the interface chip provided by CYPRESS Company. This testcontroller greatly improves the speed of data transmission, and has function of onlineupgrade, which is easy to use, and strong commonality. Taking the multi-board electronic test circuit board as an object, this paperprovides an actual testing experiment by the boundary scan test system mentionedabove. Experiments results show that the hardware system is with stable operation,accurate test, high precision, and has practical value.