A Novel Post-Silicon Debug Mechanism Based on Suspect Window

Jianliang GAO  Yinhe HAN  Xiaowei LI  

Publication
IEICE TRANSACTIONS on Information and Systems   Vol.E93-D   No.5   pp.1175-1185
Publication Date: 2010/05/01
Online ISSN: 1745-1361
DOI: 10.1587/transinf.E93.D.1175
Print ISSN: 0916-8532
Type of Manuscript: PAPER
Category: Information Network
Keyword: 
debug,  scan dump,  real-time trace,  suspect window,  

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Summary: 
Bugs are becoming unavoidable in complex integrated circuit design. It is imperative to identify the bugs as soon as possible through post-silicon debug. For post-silicon debug, observability is one of the biggest challenges. Scan-based debug mechanism provides high observability by reusing scan chains. However, it is not feasible to scan dump cycle-by-cycle during program execution due to the excessive time required. In fact, it is not necessary to scan out the error-free states. In this paper, we introduce Suspect Window to cover the clock cycle in which the bug is triggered. Then, we present an efficient approach to determine the suspect window. Based on Suspect Window, we propose a novel debug mechanism to locate the bug both temporally and spatially. Since scan dumps are only taken in the suspect window with the proposed mechanism, the time required for locating the bug is greatly reduced. The approaches are evaluated using ISCAS'89 and ITC'99 benchmark circuits. The experimental results show that the proposed mechanism can significantly reduce the overall debug time compared to scan-based debug mechanism while keeping high observability.