PPT Slide
3 – Combinational Logic Implementation
ROM approach advantageous when
- (1) design time is short (no need to minimize output functions)
- (2) most input combinations are needed (e.g., code converters)
- (3) little sharing of product terms among output functions
- ROM problems: size doubles for each additional input can't exploit don't cares
PLA approach advantageous when
- (1) design tools are available for multi-output minimization
- (2) there are relatively few unique minterm combinations
- (3) many minterms are shared among the output functions
- PAL problem: constrained fan-ins on OR plane