一种基于折叠计数器重新播种的确定自测试方案

A DETERMINISTIC BIST SCHEME BASED ON RESEEDING OF FOLDING COUNTERS

提出了一种基于扫描自测试的确定与混合模式新方案 ,这种方案依赖于一个新型的模式生成器 ,它主要配备一个可编程的约翰逊计数器 ,称之为折叠计数器 .这种新技术首先使用一个小的线性反馈移位寄存器(L FSR) ,生成伪随机测试模式测试容易测试的故障 ,并且获得一个硬故障测试立方集 T;其次采用经典的输入精简技术 ,集合 T的测试立方宽度可以被压缩 ;最终为了能够找出合理的小数目折叠计数器种子 ,来生成这个确定的测试立方集 T,给出了其理论背景和实用算法 .试验结果表明 ,这个所建议的方案与先前所公布的基于线性反馈移位寄存器和约翰逊计数器的重新播种方法相比 ,具有非常出色的结果 .因此它提供了一种有效的。

A new scheme for deterministic and mixed mode scan based BIST is presented in this paper. It relies on a new type of test pattern generator which resembles a programmable Johnson counter and is called folding counter. Firstly, this new technique uses a small LFSR to generate pseudo random patterns to eliminate the easy to detect faults and obtain a set T of hard fault test cubes. Secondly, the test cube width of the set T may be compressed with classical technique—input reduction. Finally, both the theoretical background and practical algorithms are presented to characterize the set T of deterministic test cubes by a reasonably small number of seeds for a folding counter. Experimental results show that the proposed scheme outperforms previously published approaches based on the reseeding of LFSRs or Johnson counters. It therefore provides an efficient and flexible solution for scan based BIST.