The Coding Scheme Of Relative Run Length Based On Adjacent Bit Logic Operation

With the rapid development of the integrated circuit industry,the data to be carried by the integrated circuit becomes a huger,and more and more intellectual property cores are integrated on silica gel wafers,but the chip tends to be miniaturized and intelligently developed.It is necessary to enhance the performance of the chip,and the complexity of the chip means that the faults encountered in the performance test of the chip are more complex.At present,there are several problems to be solved: shorten test time,reduce test energy consumption,lessen test data volume and so on.Test data compression is one of the most commonly used methods.This paper introduces the research background and current situation of data compression technology,the related knowledge of the system chip and the challenges it faces,summarizes several common data compression methods,and makes a comparison and improvement measures to these methods.As far as the automatic test equipment is concerned,the traditional coding method is mainly by encoding the continuous 1 run and the continuous 0 run in the test data.The analysis of the test set shows that there are not only the continuous 0 run and the continuous 1 run,but also the continuous 0 run and the continuous 0 run in the test data.There are also a large number of alternating 10 runs and alternating 01 runs.When the traditional coding method encodes this alternating run,the length of the code word has no advantage over the original length,or even longer than the original length.This does not achieve the effect of data compression.In this paper,a coding scheme of relative run length based on adjacent bit logic operation is proposed.Using adjacent bit logic operation,the average length of run length of test data can be increased by reducing the number of run lines of test data under the condition of invariant total data.All the alternating 10 runs and the alternating 01 runs are converted into continuous runs,and the encoded data is reduced by encoding the relative run length.This experiment is programmed in JAVA language.Experiments on ISCAS 89 parts of standard circuits show that the proposed coding method has very good compression efficiency.