BUS CONTENTION CIRCUIT

A bus contention circuit, is employed for each unit of a system capable of seizing use of a bus, wherein the units are arranged in a priority order. Priority resolution is accomplished by registering a request to seize use of the bus from any unit where either (1) no other requests are so registered or (2) the requesting unit is of lower priority than a unit whose request is already registered. When the bus becomes available for use, use is allocated to the unit with highest priority whose request is already registered.