摘要 |
In a digital data processing system having a resource which is shared between a plurality of users, an arbitration system comprises a plurality of resource requestors (14 to 16) each associated with a respective user, and a resource grantor (10) to which the requestors are connected in parallel via a set of common lines (11 to 13). Each resource requester is adapted to apply a request signal on a predetermined first one (11) of the lines when the associated user requests the resource, and the resource grantor is responsive to the presence of a request signal on the first line to subsequently apply a grant signal on a predetermined second one (12) of the lines to grant the resource. Each resource requestor requesting the resource is responsive to the grant signal to apply an accept signal on a predetermined third one (13) of the lines after a delay which is different for each resource requestor and which determines the priority of the user associated with the resource requestor. The first accept signal so applied gives the resource to the associated user and prevents any other resource requestor from applying an accept signal on the third line until the resource is relinquished by the current user. |