Data processing system having units competing for access to shared resources and arbitration unit responsive to the status of the shared resources

摘要

In a data processing system where a plurality of requesting units (7,12,10,40) or "masters" compete for access to shared resources (8,9,10) through a communication bus (11) by means of access request signals sent to an arbitration unit (13) and indicating a resource as requested to perform an operation, the arbitration unit grants access to the one of the requesting units having higher priority, taking in account the status of the requested resource which must be available to perform the requested operation.;Status of the resource may be provided by the resource to the arbitration unit or may be established by the arbitration unit, based on previously granted accesses.