ESE 382 Lecture Notes - Lecture 6: Sequential Logic, Ultrahle, Vhdl

• School: Stony Brook University
• Department: Electrical Engineering
• Course: ESE 382
• Professor: Kenneth Short

Document Summary

Based on their approach to performing simulation, there are three common kinds of simulators for digital systems: time driven, event driven, and cycle based. In a time-driven simulation, simulation time is advanced in predetermined uniform increments. As time is advanced, any events in the next time step are simulated. The fixed size of the time step determines the resolution with which events can be observed. For example, simulation time might be advanced in 1 ns steps. During a time-driven simulation, there are typically a very large number of time steps during which there are no events. In an event-driven simulation, time is advanced in nonuniform steps whose sizes depend on when events occur. An event-driven simulator responds to each input event by executing a sequence of simulation cycles that determine when and to what values the simulated system"s signals change.