A new test data compression/decompression scheme to reduce SOC test time

A new test data compression/decompression scheme based on Huffman coding is proposed in this paper for reducing the amount of test data transferring between ATE and CUT so as to shorten the test time of IP core-based SOC designs. The compression algorithm accomplishes in two steps - first, don't cared bits in the original test data are specified by a dedicated algorithm; then a Huffman-coding-like procedure would be applied to the fully-assigned test data. Instead of splitting test data into fix-length blocks, as it is in traditional Huffman coding, in our approach, the test data are partitioned into blocks of two lengths, namely shortWord and longWord. Both theoretical analysis and experimental results show that our scheme results in high compression ratio as well as small decompression overhead.