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:
Jun. 27, 2000

Filed:

Jan. 29, 1998
Applicant:
Inventor:

Yasuo Yamada, Chiba, JP;

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C06F / ;
U.S. Cl.
CPC ...
714 30 ;
Abstract

When testing internal state of one chip micro-computer having a CPU and a ROM installed in a single package, data D read from the ROM is subjected to non-degenerate conversion using data DT from the outside and is executed as a command code by the CPU in a test mode. To input the data DT which can serve as a correct command code from the outside, it is necessary that the data D is known. A third party is incapable of conducting a test for testing the internal state and wrongfully reading the written data.


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