Title :
Deviation-Based LFSR Reseeding for Test-Data Compression
Author :
Wang, Zhanglei ; Fang, Hongxia ; Chakrabarty, Krishnendu ; Bienek, Michael
Author_Institution :
Cisco Syst. Inc., San Jose, CA
Abstract :
Linear feedback shift register (LFSR) reseeding forms the basis for many test-compression solutions. A seed can be computed for each test cube by solving a system of linear equations based on the feedback polynomial of the LFSR. Despite the availability of numerous LFSR-reseeding-based compression methods in the literature, relatively little is known about the effectiveness of these seeds for unmodeled defects, particularly since there are often several candidate seeds for a test cube. We use the recently proposed output deviation measure of the resulting patterns as a metric to select appropriate LFSR seeds. Experimental results are reported using test patterns for stuck-at and transition faults derived from selected seeds for the ISCAS-89 and the IWLS-05 benchmark circuits. These patterns achieve higher coverage for transition and stuck-open faults than patterns obtained using other seed-generation methods for LFSR reseeding. Given a pattern pair (p 1, p 2) for transition faults, we also examine the transition-fault coverage for launch on capture by using p 1 and p 2 to separately compute output deviations. Results show that p 1 tends to be better when there is a high proportion of do-not-care bits in the test cubes, while p 2 is a more appropriate choice when the transition-fault coverage is high.
Keywords :
data compression; shift registers; ISCAS-89 benchmark circuit; IWLS-05 benchmark circuit; deviation-based LFSR reseeding; feedback polynomial; linear feedback shift register; test-compression solutions; test-data compression; transition faults; transition-fault coverage; Defect coverage; linear feedback shift register (LFSR) reseeding; output deviation; seed selection; test compression;
Journal_Title :
Computer-Aided Design of Integrated Circuits and Systems, IEEE Transactions on
DOI :
10.1109/TCAD.2008.2009166