Image Number 7 for United States Patent #4980854.
A system and method for nodes to obtain access to a bus. In this arbitration method, a central arbiter selects a particular node and issues a conditional grant. The conditional grant is transmitted before it is determined whether access to the bus will actually transfer to another node. Each node contains distributed logic that examines an extend bus cycle signal to determine whether it can become a transmitter to transfer messages on the bus. When a node becomes a transmitter, it generates an extend bus cycle signal to maintain access to the bus when executing a multi-cycle transfer, even though other nodes, perhaps with higher priorities, require access to the bus.