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. 25, 1998
Filed:
Jul. 13, 1995
Gobi R Padmanabhan, Sunnyvale, CA (US);
Joseph M Zelayeta, Saratoga, CA (US);
Visvamohan Yegnashankaran, Redwood City, CA (US);
James W Hively, Sunnyvale, CA (US);
John P Daane, Saratoga, CA (US);
LSI Logic Corporation, Milpitas, CA (US);
Abstract
A code mechanism is provided in an integrated circuit for identifying the integrated circuit such as by serial number or for use in enabling the circuit and equipment housing the circuit. Fuses, antifuses, and programmable field effect transistors are used in an array for establishing a code. The code can be established by loading a register through the array and then reading the register. Alternatively,the contents of the register can be compared with a code provided by a user to enable the circuit. In another embodiment, a ROM is loaded with a table of encryption keys, and a user addresses the ROM by loading an address in a register or in a RAM.