Test Data Compression Using Golomb Codes

In this chapter1, we present a new test data compression method and decompression architecture based on variable-to-variable-length Golomb codes. The proposed method is especially suitable for encoding precomputed test sets for embedded cores in a system-on-a-chip (SOC). We then extend the decompression scheme to make effective use of Golomb coding and the internal scan chain(s) of the core under test. This provides significantly better results than a recent compression method that uses Golomb coding and a separate cyclical scan register (CSR). In addition, the novel interleaving decompression architecture allows multiple cores in an SOC to be tested concurrently using a single ATE I/O channel. The major advantages of Golomb coding of test data include very high compression, analytically predictable compression results, and a low-cost and scalable on-chip decoder.