Bus bridge with distribution of a common cycle clock to all bridge portals to provide synchronization of local buses, and method of operation thereof
First Claim
1. A bus bridge for interconnecting a plurality of buses, comprising:
- a plurality of bridge portals, each bridge portal being coupled to a respective one of the buses;
a plurality of switching subsystems, each coupled to a respective one of the bridge portals and which collectively form a switching system which interconnects the plurality of bridge portals; and
a plurality of cycle clock subsystems, each operatively associated with a respective one of the bridge portals and the respective switching subsystem coupled to the associated bridge portal;
wherein each cycle clock subsystem comprises;
a cycle clock generator for generating a cycle clock; and
a cycle counter which receives the cycle clock at a reset input thereof, and which produces a cycle count output which constitutes a common timing reference for the respective switching subsystem and the respective bridge portal;
and further wherein the cycle count output generated in one of said subsystems is distributed to the cycle counters of all other of said subsystems to provide a common timing reference for the bridge portals of all of said buses, the bridge portal associated with said one subsystem being a cycle monster portal.
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Abstract
A bus bridge for interconnecting a plurality of buses, which bridge includes a plurality of bridge portals, each portal being coupled to a respective one of the buses, and further includes a plurality of switching subsystems, each of which is coupled to a respective one of the bridge portals. The plurality of switching subsystems collectively constitute a switching system which interconnects the plurality of bridge portals. The bus bridge further includes a plurality of cycle clock subsystems, each of which is operatively associated with a respective bridge portal and the respective switching subsystem coupled thereto. Each cycle clock subsystem includes a cycle clock generator which generates a cycle clock, and a cycle counter which receives the cycle clock at a reset input thereof and produces a cycle count output which constitutes a common timing reference for the respective switching subsystem and the respective bridge portal. The bus bridge is preferably an IEEE 1394 serial bus bridge. Various specific implementations of the switching subsystems and bridge portals are disclosed.
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Citations
27 Claims
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1. A bus bridge for interconnecting a plurality of buses, comprising:
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a plurality of bridge portals, each bridge portal being coupled to a respective one of the buses; a plurality of switching subsystems, each coupled to a respective one of the bridge portals and which collectively form a switching system which interconnects the plurality of bridge portals; and a plurality of cycle clock subsystems, each operatively associated with a respective one of the bridge portals and the respective switching subsystem coupled to the associated bridge portal; wherein each cycle clock subsystem comprises; a cycle clock generator for generating a cycle clock; and a cycle counter which receives the cycle clock at a reset input thereof, and which produces a cycle count output which constitutes a common timing reference for the respective switching subsystem and the respective bridge portal; and further wherein the cycle count output generated in one of said subsystems is distributed to the cycle counters of all other of said subsystems to provide a common timing reference for the bridge portals of all of said buses, the bridge portal associated with said one subsystem being a cycle monster portal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method for distributing a cycle clock in a bus bridge which includes a plurality of buses and bridge portals, each bridge portal being coupled to a respective one of the buses, and which further includes a plurality of switching subsystems respectively coupled to respective ones of the bridge portals, the plurality of switching subsystems collectively forming a switching system which interconnects the plurality of bridge portals;
- said method comprising the steps of;
at each bridge portal, generating a cycle clock; at each bridge portal, using a cycle counter to produce a cycle count output; and using the cycle count output to produce a common timing reference for both the bridge portal and the respective switching subsystem coupled thereto. - View Dependent Claims (27)
- said method comprising the steps of;
Specification