多扫描链测试集的分组标准向量压缩法

Standard Vector Compression Based on Test Set Grouping for Multiple Scan Chains

针对相容压缩方法对确定位分布不平衡的测试数据集的压缩效果不佳的问题,将测试集按多扫描链结构排列后,根据向量之间相同相容关系的数目将测试集划分为若干组,分别对各组实行相容压缩;再次排列后,用标准向量差分法进行差分,并运用距离标记法对差分向量作第二次压缩.该方法对确定位分布不平衡的测试集有较高的压缩率,且向量差分时所需的循环移位寄存器数目少.

To cope with the problem that the compatible compression is inefficient for the test set with unbalanced distributed deterministic bits. This paper proposes the following method. First, the test set is formatted according to the multiple scan chains. Then it is divided into several groups by the number of same compatible relations among vectors. And each group does the compatible compression. Next, the results are rearranged and the differences vectors are gained by standard vector difference method. Finally, the differences vectors are compressed using the distance-marking method. This method performs well in compressing the unbalanced distribution of the deterministic bits, and the number of the cyclical scan registers is small.