文中提出了一种新颖的基于确定位个数相等切分的LFSR(线性反馈移位寄存器)重新播种方法。针对确定性测试集中不同的测试向量所包含确定位的位数差异较大的特点,将所有测试向量串成一条数据流,按照确定位个数相等的策略对该数据流进行切分,然后对得到的新测试向量集进行LFSR编码,达到提高测试数据压缩率的目的。本方案解压结构仅需单个LFSR和一个简单的控制电路,且由于等长度的种子解压时测试数据传输协议简单。与目前国内外同类方法相比,具有测试数据压缩率高、解压结构简单及硬件开销较小等特点。
A novel scheme of LFSR(linear feedback shift register) reseeding method based on dividing test cubes by equal number of specified bits is presented in this paper. As the number of specified bits of different test patterns varies widely in a deterministic test cube, all test patterns are concatenated to a data flow. The data flow is divided by equal number of specified bits into new test patterns, and then these new test patterns are encoded by LFSR. Thus the proposed scheme reaches the target of increasing the encoding efficiency. The decompression structure of the proposed scheme only contains a LFSR and a simple control circuit. Its transmission protocol of decompression for transmitting test data is also simple because of the seeds with the same length. Compared with the previous schemes, the proposed scheme can increase the encoding efficiency with simple decompression structure and less area overhead.