Regular structures for two-level logic
ROM: Full AND plane, general OR plane
- Simple to design
- Medium speed
- Can implement any function of n inputs
PLA: Programmable AND and OR planes
- Complex to design
- Slow (two programmable planes)
- Can implement any function up to # of product terms
PAL: Programmable AND plane, fixed OR plane
- Moderate to design
- Fast (one programmable plane that is smaller than ROM decoder)
- Can implement any function limited by # of AND or OR terms