Fundamentals of Industrial Electronics

21

Digital Design—Sequential Logic

Sin Ming Loo

Boise State University

Arlen Planting

Boise State University

21.1    Combinational and Sequential Logic

21.2    Memory Elements

21.3    Designing an Up Counter

21.4    Designing a Sequence Detector

21.5    Summary

References

21.1    Combinational and Sequential Logic

Memory is the difference between combinational and sequential logic. With combinational logic, the output is generated from inputs (after some gate propagation delays through the logic gates). Propagation delay is the length of time from when the input to a logic gate is valid, to the time when the output of that logic gate is valid. The propagation time will determine how soon a new set of inputs can be processed with the output correctly ...