Patent ID: 7433989
Filing Date: 2008-10-07
Classification: G06F

Abstract:
1. An arbitration method of a bus bridge that interfaces a primary-side bus with a plurality of secondary side buses, the primary-side bus being a local bus in a system and the secondary side buses being external buses connected to the system, the bus bridge supporting a plurality of kinds of operations one of which is a serial bus operation in accordance with IEEE 1394, one of the second-side buses being a serial bus in accordance with IEEE 1394 and the rest of the secondary-side buses are card buses, the bus bridge having a first arbiter and a second arbiter, the first arbiter performing an arbitration granting equal access to each of the plurality of buses, the second arbiter performing an arbitration between the card buses and providing an input to the first arbiter, the arbitration method comprising the steps of: when accessing the primary-side bus, and if access requests made by three bus masters including more than two kinds are issued through the secondary-side buses, performing an arbitration by said first arbiter granting equal access to each of the plurality of buses; and performing the same kind of arbitration by said second arbiter and inputting to the first arbiter an output of the second arbiter, thereby giving an access right equally to each of the secondary side buses.