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:
Mar. 05, 1996
Filed:
Jul. 15, 1994
Applicant:
Inventor:
Hartmut Schrenk, Haar, DE;
Assignee:
Siemens Aktiengesellschaft, Munich, DE;
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
G06F / ;
U.S. Cl.
CPC ...
39518801 ; 365201 ;
Abstract
In a method and circuit for protecting circuit configurations having an electrically programmable non-volatile memory used as a non-volatile counter, an access check is provided in the circuit configuration by comparison of a check code to be fed in with a secret code. Each counter bit is evaluated immediately after programming the counter bit. A protected function is disabled in dependence on the recognition of the counter bit as written. The reading level is set during the evaluation of a particular counter bit to be more-critical than in all of the later reading operations of the counter bit.