The Research On Full-automation Test With Boundary Scan

With the development of the micro-electronics, it is difficult to test the complicated circuit quickly and efficaciously by traditional test method, while boundary scan technology which applies to the digital integrates circuits is an integrated and standardized solution to the test of component-functionality, board interconnection and interaction, which facilitates the debugging of system circuitry.Boundary-Scan Test (BST) attaches a Boundary-Scan Cell (BSC) to each I/O pin to accomplish the test of soldering and linking chips in PCB. This paper is designed a PC-based test platform, which use USB 2.0 realizes the high-speed data communication between PC and the boundary-scan test controller, with the characteristics of the full-automation test PCB fault diagnosis.In this paper we proposed a good test controller design from both of the hardware and software aspect to increase the speed of boundary-scan test automation after studying some important kinds of test techniques. In terms of hardware, the controller design for the four functional modules, namely the USB interface unit, control and converter unit, dual-port memory cells, TAP interface unit. While on the software hand, the most important thing is the USB-driven design, because the data communication between PC and the controller is most important, when we chose the Cypress's EZ-USB series chips, which provided the framework greatly simplifies the design of our procedures. In addition, a kind of improved algorithm for interconnect test was put forward based on the research experience of traditional vector generation algorithm. This algorithm can avoid the phenomenon of aliasing syndrome, minimized the compact index and shortened the test time which compared with other algorithms.Combined with hardware and software designed to the improved test vector generation algorithm greatly enhanced boundary-scan controller's automation.