Exploration Of Boundary Scan Application In In-Circuit Test Of Circuit Pack

This thesis discusses the realization of PCBs ICT production through a concrete example in which boundary scan technology is applied, and presents a new method to improve the test speed, based on the analysis of boundary scan circuit and means for vector creation.He applys boundary scan (BS) to boundary-scan device on the board where BS features by easy vector creation, need less knowledge of the device. Consequently it paves the way to ease the difficulty of vector creation. But BS still requires large number of vectors. So here introduces a new method-the combination of boundary scan with DeltaScan, in which DeltaScan is applied to do short and open test in ICT, so that the number of vectors used to test circuit short and open in boundary can be eliminated.All vector test, including boundary scan test, need to create test vectors. There are a lot of methods available to create test vector. The thesis addresses their characteristics of the methods and special structure of boundary scan circuit respectively and come to a conclusion of pseudo-exchausive testing the most rational method applied to this situation.The article also addresses the mechanism of vector creation for boundary scan. The majority of the test vectors are used to check the connection of the pins of the device. Those vectors for connection test can be removed from the vector base for the device under test when DeltaScan is applied together with boundary scan test. The total vectors are therefore eliminated.Test development procedure is given in the article, with test vectors and test program lists appended. It is seen from the result of the experiment that Pseudo Exhaustive Test with DeltaScan involvement is truly a simple and practical method to produce vectors for boundary scan, it is suitable for any kinds of boundary scan devices. This method presents universality and depends weakly on test system. It fits well to single output without fan-out. One thing should be kept in mind, don't just mechanistically copy this method in practice, but seize the essential.