Priority arbiters

Abstract

The paper presents asynchronous design solutions to the problem of Priority Arbitration which is defined in the following form. A system consists of multiple, physically concurrent, processes with a shared resource. The discipline of resource allocation is a function of parameters of the active requests, which are assigned to the requests either statically or dynamically. This function can be defined in an (arbitrary) combinatorial way (contrary to conventional, 'topological', mappings, such as that used in a daisy-chain arbiter). The proposed designs are quasi-speed-independent. Furthermore, the priority logic, in the dynamic case, has the following architectural feature: it is a tree structure in which the control flow is maximally decoupled from the data-path by means of an early propagation of the 'valid'-'invalid' signals, concurrently, with processing the priority data. This lends to significant reduction in the overall arbitration delay when the number of active requests is low.