EP0137761A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Multi-master communication bus system with parallel bus request arbitration
Assignee: Northrop Grumman Space and Mission Systems Corp
•
Filing: 1984-09-19
•
Granted: —
•
Expires: 2004-09-19
Abstract
Abstract Apparatus and a related method for regulating access to a communication bus to which multiple communication nodes are connected. Control logic at each of the nodes determines which of them has priority to access the bus, by means of a parallel arbitration sequence in which all nodes contending for bus access participate. Specifically, each contending node generates a relative priority node number and asserts it onto an arbitration bus. All of the asserted node numbers are logically combined into a composite node number on the bus, and the winning node is determined in a bit-by-bit ripple comparison circuit at each node, the composite node number being compared with the locally generated relative priority node number. Priority is determined in advance of data transmission, and synchronization and arbitration take place without any central or master control unit.
Inventors
- 👤 Kenneth Hok-Kun Szeto
- 👤 Frank Avery Hill
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 01:34
CPC Classifications
G; G06; G06F; G06F13/00; G06F13/14; G06F13/36; G06F13/368; G06F13/374
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
194 words
A multi-master communication bus system comprising: a plurality of communication nodes, each node being assigned a unique identifying number; a data bus for the transmission of information from node to node; an arbitration bus for the transmission of signals for the resolution of conflicts between multiple requests for bus access; means located at each node and responsive to a locally generated request for bus access, for determining a relative node priority number as a function of the identifying number of that node and the identifying number stored in the previous node register, and for asserting the relative node priority number onto the arbitration bus; means for generating on said arbitration bus a composite node number from all relative node priority numbers asserted onto said bus; bus request resolution means located at each node for detecting the composite node number and determining therefrom whether the request for bus access is successful; means located at each node for asserting onto said ' arbitration bus the identifying number of that node when it is granted bus access; and a previous node register for storing the identifying number of the most recent node to be granted bus access.
Claim 2
Dependent Claim
194 words
A multi-master communication bus system comprising: a plurality of communication nodes, each node being assigned a unique identifying number; a data bus for the transmission of information from node to node; an arbitration bus for the transmission of signals for the resolution of conflicts between multiple requests for bus access; means located at each node and responsive to a locally generated request for bus access, for determining a relative node priority number as a function of the identifying number of that node and the identifying number stored in the previous node register, and for asserting the relative node priority number onto the arbitration bus; means for generating on said arbitration bus a composite node number from all relative node priority numbers asserted onto said bus; bus request resolution means located at each node for detecting the composite node number and determining therefrom whether the request for bus access is successful; means located at each node for asserting onto said ' arbitration bus the identifying number of that node when it is granted bus access; and a previous node register for storing the identifying number of the most recent node to be granted bus access.
Claim 3
Dependent Claim
54 words
A multi-master communication bus system as set forth in claim 1, wherein said means for determining and asserting a relative node priority determines the relative node priority as equal to the difference between the number of the local node and the number of the node that was the last to be granted bus access.
Claim 4
Dependent Claim
46 words
A multi-master communication bus system as set forth in claim 2, wherein: the relative node priority is obtained by subtracting the number of the last node to be granted bus access from the local node number, and treating the two's complement difference as an unsigned integer.
Claim 5
Dependent Claim
130 words
A multi-master communication bus system as set forth in claim 3, wherein: said means for generating a composite node number operates as a logical OR circuit; and said bus request resolution means includes a bit-by-bit ripple comparison circuit for comparing the composite node number with the locally generated relative node priority, means associated with said comparison circuit for removing the locally generated relative node priority from assertion on said arbitration bus if said comparison circuit detects nonmatching bits, and means for generating a signal indicative of bus grant if all corresponding bits in the compared node numbers match, whereby removal of a relative node priority from assertion on said arbitration bus results in regeneration of the composite node number and removal of the local node from contention for bus access.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.