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:
Dec. 02, 1997
Filed:
Aug. 27, 1996
Sonali Bagchi, Allentown, PA (US);
Jalil Fadavi-Ardekani, Orefield, PA (US);
Kenneth Daniel Fitch, Allentown, PA (US);
Daisuke Takise, San Jose, CA (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
An integrated circuit counter is capable of implementing a relatively high count while being testable using a relatively low number of clock cycles. A linear-feedback shift register (LFSR) having n bit positions is used as the counter. The feedback path of the shift register includes an exclusive OR (XOR) gate that couples selected bits back to the input of the register, in order to implement a 2.sup.n -1 counter. Combinatorial logic circuitry is included to test the counter in significantly less than 2.sup.n -1 clock cycles. This allows for implementing a testable 'watchdog timer' that may be used to detect software runaway conditions in microprocessor systems, among other uses.