The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Feb. 03, 2009

Filed:

Aug. 26, 2003
Applicants:

Yoshitaka Kayukawa, Kanagawa, JP;

Tetsuya Aoki, Tokyo, JP;

Takahiro Hamaguchi, Kanagawa, JP;

Noriyuki Oshima, Kanagawa, JP;

Inventors:

Yoshitaka Kayukawa, Kanagawa, JP;

Tetsuya Aoki, Tokyo, JP;

Takahiro Hamaguchi, Kanagawa, JP;

Noriyuki Oshima, Kanagawa, JP;

Assignee:

Sony Corporation, Tokyo, JP;

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01R 31/3177 (2006.01); G01R 31/40 (2006.01);
U.S. Cl.
CPC ...
Abstract

An LSI which makes scan testing possible without compromising security is provided. Flip-flops that constitute a scan chain are reset when scan testing is initiated or terminated by the edges of a mode signal for switching between normal operations and scan testing. In addition, during scan testing, internal memory means is made inaccessible. Further, a dummy flip-flop that operates only during scan testing is connected to the scan chain, and shifting out by the scan chain during normal operations is made impossible.


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