CSC270   HW #4

Problem #1

Problem 4-9. For this problem provide the Boolean expressions for all the outputs, but draw the logic or circuit diagram for only 2 or 3 of the outputs (drawing all of them would take many pages!)

Problem #2

Problem 4-34

Problem #3

Design a traffic-light sequencer based on D-flip-flops that has three output lights, Green, Yellow, and Red, and that works off a power-supply that has a reset signal (active low).

Your sequencer should energize the lights in the following order: Green first, then Yellow, then Red, followed by Green again. The green light will stay on for 3 seconds, the yellow for 2 seconds, and the red light for 2 seconds as well.

You have available a circuit that generates a clock signal with a frequency of 1 Hz.

Your answer should have the following information:

• A state diagram
• The assignment of outputs to states
• A state table showing the Q outputs, the D inputs, and the Light signals.
• A diagram with the flip-flops, the combinational circuits used to generate the D-inputs, and the combinational circuits used to generate the light signals.

Problem #4

Assume now that we want the same behavior of the traffic lights circuit of Problem 1 (3 seconds green, 2 seconds yellow, 2 seconds red), but this time the clock signal available has a frequency of 4 Hz.

Can you somehow find a way to keep much of your previous design?

Show your new diagram, and highlight the parts in it that are taken directly from your answer to the first problem.

Problem #5

Problem 5-8

Problem #6

Problem 5-18