基于响应分块相容的测试数据编码压缩方案

The Blocks' Compatibleness Test Data Compression Using Internal Scan Chains

提出一种测试数据压缩方案,利用测试向量与扫描链中响应数据的分块相容来增加被编码测试向量中的无关位,降低了线性反馈移位寄存器(LFSR)编码种子的度数,且不必增加额外的测试向量,最终达到压缩测试数据的目的.该方案的硬件解压结构仅需一个LFSR和简单的控制电路.实验结果表明,与其他压缩方法,如基于部分向量切分的LFSR重新播种方法、混合码方案和FDR码方案等相比,该方案在压缩效率和硬件开销上都有明显优势.

A test data compression scheme, based on blocks＇ compatibility between responses and test vectors, is presented. In the scheme, don＇t care bits in test vectors can be increased by using the blocks＇ compatibility between responses and te^t vectors. The length of encoding LFSR is reduced without any additional test vectors, and therefore the test set can be compressed. The decompression structure needs only an LFSR and a simple control circuit. Experimental results indicate that the proposed scheme provides a higher ratio of test data compression than the other test data compression strategies such as the syncopation method, the hybrid coding strategy, and the FDR coding, with little hardware overhead.