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:
Oct. 12, 2010
Filed:
Jul. 12, 2005
Stuart A. Nisbet, Edinburgh, GB;
Gareth D. Edwards, Edinburgh, GB;
Stuart A. Nisbet, Edinburgh, GB;
Gareth D. Edwards, Edinburgh, GB;
Xilinx, Inc., San Jose, CA (US);
Abstract
A method and apparatus for improving enforcement of the time-limited operation of a programmable device. Two random number generators, e.g., linear feedback shift register (LFSR) circuits, are utilized in which a first LFSR provides free-running capability, while a second LFSR provides time-sensitive capability. The states of the two LFSR circuits are compared by various portions of the programmable device at each state transition in order to obtain authorization to continue operation. Authorized operation continues as long as the states of both LFSRs are equivalent, or at least equivalent, within a given phase offset. Once a terminal count of the time-sensitive LFSR is reached, then authorization for continued operation ends and at least a portion of the programmable device is disabled.