Test Data Coding Scheme Based On Binary Algorithm

With the improvement of the level of integrated circuit manufacturing technology,the integrated circuit has entered the nanometer size.According to Moore's Law,the integrated number of transistors on a single chip will still increase exponentially in the future.Such a sharp development speed will inevitably increase the difficulty of testing.It is accompanied by the cost of the cost.Faced with the huge amount of test data,higher requirements are placed on the hardware performance and feasibility of expensive automatic test equipment(ATE),and the time,power consumption and complexity problems faced by the test are essentially Cost loss.Therefore,in order to solve the fundamental problem of this test,the research of the subject has key and practical significance.At present,most researches at home and abroad start from the test data compression,and can solve the cost problem to a certain extent.The technical summary is two kinds: Built-in Self-Test(BIST)and external self-test(Built-Out Self-Test,BOST).The main idea of BIST is to propose a method of integrating test generation,data loading,response analysis and test control structure into a circuit,so that the circuit can test itself,thereby reducing the cost of testing.The external self-test is mainly to store the test data of the compressed IP core in the test device,then transfer the vector to the chip,and finally realize the data restoration by designing an external decompression circuit.This technology can reduce the amount of test data and the time required for the entire test,and has a wider range of uses.This thesis is based on the test data compression method of the external self-test technology.The research work is carried out from the preprocessing of the original data,the encoding method of the run-length division combined with the advantages of the binary algorithm.The main work of this paper is as follows:(1)By statistically analyzing the unrelated bits X contained in the original data,the irrelevant bit X is relatively high while taking into account that it does not have any influence on the test data results after filling,and the adaptive filling method is used for the unrelated bits X.Filling in "0" or "1" can make it more in line with the coding law,which has certain effects on improving coding efficiency and reducing the amount of test data.(2)The traditional double-running coding needs to mark the current code as "0" or "1" run length coding.Considering the loss of coded bits in the coding process,it is proposed to use untagged under a certain decimal.The method of double-running alternate coding can solve the problem of the number of bits of the mark bit loss,effectively reduce the number of run bits and improve the test compression rate.(3)Considering the advantages of coding compression and binary algorithm,in the integer binary part,the run-length integer is used,and the case of integer two-point is recorded,and a certain compression effect can be obtained in different decimals;The encoded run is treated as a fractional number.The binary search algorithm is used to record the regularity of the search process.At the same time,the corresponding decoding circuit is designed to realize the lossless reduction of the test data.Therefore,the coding method of this paper provides an effective method for reducing the length of code words and reducing hardware overhead,and reducing the original test data and reducing the cost of testing.