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.

Date of Patent:
Sep. 20, 1994

Filed:

Feb. 11, 1993
Applicant:
Inventors:

Robert C Frame, Westboro, MA (US);

Fernando A Zayas, Worchester, MA (US);

Edward A Gardner, Colorado Springs, CO (US);

Assignee:

Digital Equipment Corporation, Maynard, MA (US);

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F / ; G06F / ; G06F / ; G06F / ;
U.S. Cl.
CPC ...
395800 ; 3642289 ; 364229 ; 3642292 ; 3642295 ; 3642301 ; 3642386 ; 3642389 ; 364240 ; 3642401 ; 3642405 ; 3642416 ; 3642426 ; 36424292 ; 364D / ; 364D / ;
Abstract

A method and apparatus for selecting a particular node from a plurality of nodes connected to a common bus to allow the node to use the bus. The nodes have a pre-determined priority. After initially enabling the nodes, the bus is monitored for a bus idle condition. It is then determined which of the nodes are enabled message nodes, which are enabled nodes that have a message to send on the bus. There is then arbitration between the enabled message nodes after the bus is in the bus idle condition for a first period of time, such that the enabled message node having the highest pre-determined priority among the enabled message nodes is disabled for arbitration purposes, and also at the same time selects a target and performs a transfer. This procedure is repeated until all the enabled message nodes have been disabled. Thereafter, all of the nodes on the bus are enabled when the bus is in the bus idle condition for a second period of time, which is longer than the first period of time.


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