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:
Feb. 25, 2003
Filed:
Nov. 02, 2001
James L. McManus, Longmont, CO (US);
Eric J. Crabill, San Jose, CA (US);
James L. Burnham, Morgan Hill, CA (US);
Xilinx, Inc., San Jose, CA (US);
Abstract
A core for a register-based programmable logic device includes a register configured to provide a hidden identifier in response to a secret unlock operation. The identifier is inaccessible during normal operation of the core implementation. The unlock operation is selected to be an action or set of actions that would typically not be performed during normal use of the core implementation. The logic associated with providing the hidden identifier in response to the unlock operation is configured to not interfere with normal operation of the core implementation. Therefore, the presence of this source identification capability is transparent to regular users (and unauthorized copyists) of the core implementation. The availability of the secondary identifier can be limited in duration to minimize the chances of accidental, or even intentional, discovery.