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. 10, 1989
Filed:
Oct. 15, 1987
Applicant:
Inventors:
Assignee:
Northern Telecom Limited, Montreal, CA;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11C / ; G11C / ;
U.S. Cl.
CPC ...
36518907 ; 365221 ; 36523002 ; 365236 ;
Abstract
A FIFO (first in first out) control circuit for providing address information to a FIFO memory uses two up counters--one to provide the write address and one to provide the read address. A multiplexer selects which addresses (read or write) are used. Two storage registers are used to temporarily 'hold' the output from the counters. This enables the counters to be re-loaded with their original 'count' to enable either a re-reading or a re-writing of a message stored in the FIFO memory. Comparators and logic circuitry are used to provide two status output signals, namely full (or not) and empty (or not).