Realization of multiple-output functions by reconfigurable cascades

A realization of multiple-output logic functions using a RAM and a sequencer is presented. First, a multiple-output function is represented by an encoded characteristic function for non-zeros (ECFN). Then, it is represented by a cascade of look-up tables (LUTs). Finally, the cascade is simulated by a RAM and a sequencer. Multiple-output functions for benchmark functions are realized by cascades of LUTs, and the number of LUTs and levels of cascades are shown. A partition method of outputs for parallel evaluation is also presented. A prototype has been developed by using RAM and FPGA. This realization uses time domain multiplexing, and is useful for the case where the number of output pins is limited.