Research On Test Data Compression Method Based On Cellular Automata

With the continuous development of integrated circuit design and continuous increasing of system integration scale,System-on-a-Chip(SoC)has emerged,and the complexity and integration has been raised to a new stage.At the same time,test data,test time and test power consumption are sharply increasing.Because of the limit of memory depth and bandwidth of Automatic Test Equipment(ATE),the overall cost of testing maintains a high level.If the performance of equipment is optimized by iterative upgrading,the cost of testing will be further escalated.In order to solve this testing problem,the industry and academia had launched an in-depth study,and then the compressing method of test data is proposed,which is one of the most effective ways.Test data compression techniques can greatly reduce the amount of test data,shorten test time and reduce test power consumption.In this thesis,we start from the test data compression method based on coding,detail the foundation of SoC testing and its related theories,introduce the main principles,structure and standards of testing,describe the concept and classification of testable design,introduce several different types of SoC testing,analyze several classical methods of test data compression.At last,according to the related theory of cellular automata and the characteristics of the cellular automata rules,proposes a comprehensive test data compression method.Firstly,based on the random vector array generated by the cellular automaton,and using exhaustive method to find the best transformation rule for test set processing,the original test set is split into two parts,the main component set and the residual set,where the main component set can be generated by the hardware circuit of the cellular automaton,and the residual set can be obtained by the heterogeneous operation between the original test vector set and the main component set.Subsequently,based on the advantage of the large number of long travels in the residual set,the residual set is encoded and compressed.Finally,according to experiment and analyze the generation characteristics of cellular automaton vectors,remove some low-dimensional invalid rules and the scheme is refined and simplified,further reducing the test time and improving the overall compression efficiency.Based on the Min Test test set,this thesis uses C language to write a program to perform compression experiments in ISCAS-89 standard circuits.The experimental results show that the proposed compression scheme has a higher average compression rate for circuits,and higher compression rate for the circuit with less irrelevant bits and a higher complexity.