On the reduction of the programming cost of soft switches for reconfigurable two-dimensional arrays
T. Liu, Fabrizio Lombardi · IEE Proceedings E Computers and Digital Techniques · 1992
Methods for reducing the cost involved in the programming of nonpermanent (soft) switching elements in an augmented interconnection network for reconfigurable two-dimensional arrays are considered. The proposed approach is based on an optimised execution of the disjoint tree programming technique proposed by Boubekeur et al. Reduction in cost is analysed with respect to either the sequential or parallel execution of the programming process for the soft switches of the array. The formulation and characterization of two different figures for evaluating the cost of switch programming are given with respect to a global reduction (rather than heuristically as in previous approaches). These figures are the highest programming cost of a tree and the overall programming cost of the array (as given by the sum of the programming costs of all trees). A new cost referred to as the adjusted cost, is introduced for establishing a relationship between the programming process and the switching modes of the target array. Reduction in cost is achieved by two techniques: redundancy reduction given by the number of times a switch is programmed in a tree, and a relaxation technique referred to as compression, in which each of the two figures of cost is primarily considered for reduction. This is achieved by iteratively deleting leaf switches to a tree while adding the same switches to adjacent trees.