Partial bus-invert coding for power optimization of application-specific systems

This paper presents two bus coding schemes for power optimization of application-specific systems: Partial Bus-Invert coding and its extension to Multiway Partial Bus-Invert coding. In the first scheme, only a selected subgroup of bus lines is encoded to avoid unnecessary inversion of relatively inactive and/or uncorrelated bus lines which are not included in the subgroup. In the extended scheme, we partition a bus into multiple subbuses by clustering highly correlated bus lines and then encode each subbus independently. We describe a heuristic algorithm of partitioning a bus into subbuses for each encoding scheme. Experimental results for various examples indicate that both encoding schemes are highly efficient for application-specific systems.