SYNTHESIS OF MULTILEVEL MULTIPLEXER CIRCUITS FOR INCOMPLETELY SPECIFIED MULTIOUTPUT BOOLEAN FUNCTIONS WITH MAPPING TO MULTIPLEXER BASED FPGAS

The introduction of the multiplexer-based Actel FPGA series ACT(TM) re sulted in an increased interest in multiplexer circuits. This paper in troduces a level-by-level top-down minimization algorithm for them. Th e concept of a local transform is applied for the generalization of th e ratio parameter method for M(1) multiplexer synthesis having one dat a select input and a spectral method for M(2) multiplexer synthesis to determine redundant multiplexer inputs for M(k) multiplexer circuits. The algorithm developed for multilevel synthesis of M(k) multiplexer circuits for incompletely specified multioutput Boolean functions take s advantage of the combination of spectral and Boolean methods. The ob tained multiplexer circuit can be directly realized with FPGA's like t he Actel ACT series or the CLi 6000 series from Concurrent Logic. A si mple heuristic is applied to map an M(1) multiplexer circuit to the Ac tel ACT1 family.