Functional Simulation (as opposed to Timing Simulation) is NOT available in the student version of the MAXPLUS+II software. I think there maybe something in the tutorial notes that says to use Functional Simulation. If so, just substitute Timing Simulation.

Functional simulation models the functionality of a design without including any timing information. (So for example it would show that two signals X,Y go high after a certain clock edge, but it they would go high at the same time, even if in the real circuit one signal were much slower than the other. Timing simulation would show the time difference.) This is faster than Timing simulation, and useful for very large designs whose timing simulation is very slow. However computers nowadays are powerful enough that even for very large designs the full timing simulation is basically instantaneous.

One other possibly important consideration is that timing simulation will show glitches, whereas functional won't. (The glitches happen when there are multiple paths in a combinational circuit, with some of the paths having longer delays, so the output will glitch until it has settled into its final state.)

Robin

-- Robin Grindley (grindley@eecg.toronto.edu), January 17, 1999