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.
Patent No.:
Date of Patent:
Aug. 19, 2008
Filed:
Oct. 21, 2003
Mitsuhiro Watanabe, Tokyo, JP;
Mitsuhiro Watanabe, Tokyo, JP;
Oki Electric Industry Co., Ltd., Tokyo, JP;
Abstract
When a test mode signal is rendered active by a signal given from an external terminal, a CPU reads and runs various self-testing programs stored in a ROM. When any of the test programs comes to a process of testing a security circuit, a security test signal is rendered active and when a predetermined address is accessed then, a selector is switched to a register side by the output signal of an AND circuit of a test circuit. An illegitimate instruction, for example, is set in the register and is given to the CPU. Whether the security circuit has failure is determined by checking if an illegitimate access detection signal is output when the CPU executes the illegitimate instruction.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile