Run-Length-Based Test Data Compression Techniques: How Far from Entropy and Power Bounds?—A Survey

[摘要] The run length based coding schemes have been very effective forthe test data compression in case of current generation SoCs witha large number of IP cores. The first part of paper presents asurvey of the run length based codes. The data compression of anypartially specified test data depends upon how the unspecifiedbits are filled with 1s and 0s. In the second part of the paper,the five different approaches for “don't care” bitfilling based on nature of runs are proposed to predict themaximum compression based on entropy. Here the various run lengthbased schemes are compared with maximum data compression limitbased on entropy bounds. The actual compressions claimed by theauthors are also compared. For various ISCAS circuits, it has beenshown that when the X filling is done considering runs of zerosfollowed by one as well as runs of ones followed by zero (i.e.,Extended FDR), it provides the maximum data compression. In thirdpart, it has been shown that the average test power and peak poweris minimum when the don't care bits are filled to make thelong runs of 0s as well as 1s.

[学科分类] 电子、光学、磁材料