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:
May. 30, 1989
Filed:
Jul. 21, 1986
Hanz W Herrig, Aurora, IL (US);
David N Horn, Rumson, NJ (US);
Daniel V Peters, Warrenville, IL (US);
Randy D Pfeifer, Warrenville, IL (US);
Wayne R Wilcox, Naperville, IL (US);
American Telephone and Telegraph Company, AT&T Bell Laboratories, Murray Hill, NJ (US);
AT&T-Information Systems, Holmdel, NJ (US);
Abstract
An electronic circuit board electrically connected to other circuits of a data processing system by means of a bus, may be removed and re-inserted in the system without the necessity of disabling other circuits connected to the bus. A latch actuated switch provides a control signal in anticipation of circuit board removal. The control signal activates a finite state machine which seizes control of the bus after completion of any current bus communications and stops the generation of clock pulses normally required in bus communications. When contact is physically broken between the board and its corresponding connector, the finite state machine restores the bus clock pulses and relinquishes control of the bus. When a board is to be inserted in an open connector, contact between the board and the connector is sensed by the finite state machine which causes the bus to be seized and the bus clock pulses to be temporarily inhibited. When the board is fully inserted, the finite state machine restores the bus clock pulses and relinquishes control of the bus.