Enhanced bus arbiter utilizing variable priority and fairness

摘要

A bus arbiter for a computer system having a bus for connection to a plurality of bus devices where each bus device requests control of bus by use of a bus request signal. The bus arbiter contains logic which incorporates a fairness scheme for controlling and prioritizing the bus request signals based on a predetermined priority of each bus device and each bus device's prior access within a fairness cycle. Each device's prior access is tracked by bits in a data register and is determined by whether or not the device actually received or sent information over the bus, and not by a simple granting of access which could result in a retry signal.