Memory and three-state Inference
· Alows the use of sequential logic in designs
· Keep designs technology-independent.
· A register is a simple, 1-bit memory device, either a latch or a flip-flop.
· A latch is a level-sensitive memory device.
· A flip-flop is an edge-triggered memory device.
· For best results
Restrict each process to a single type of memory-element :
· latch with asynchronous set or reset
· flip-flop with asynchronous reset
· flip-flop with synchronous reset.