DigitalElectronicsU1L3AtoDconverterDigital

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Problem

Since we learned how the digital electronics of the Board Game Counter worked by analyzing its sequential and combinational logic sections separately, we will construct and simulate the device the same way. We will begin with the combinational logic section.

Using Multisim, enter the combinational logic section of the Board Game Counter shown below. For testing purposes connect three switches for the inputs A, B, and C.

Combinational Logic Section – Board Game Counter

a) Start the simulation.

b) Toggle the switches and complete the truth table shown below.

A	B	C	L1	L2	L3	L4	L5	L6	L7
0	0	0
0	0	1
0	1	0
0	1	1
1	0	0
1	0	1
1	1	0
1	1	1

c) Did the outputs for the inputs 001 thru 110 display what was expected? If they didn’t, check your circuit to make sure that it was built correctly. Make any necessary corrections and repeat steps (a) and (b).

d) Did the outputs for the inputs 000 and 111 make sense? Does it matter?

Note: Do this assignment on paper, you won’t be able to enter in all of the data into the given space on this problem.

Now that the combinational logic section is working (problem 1), let’s construct and simulate it the sequential logic section. Using Multisim, enter the sequential logic section of the Board Game Counter shown below. For the initial analysis, we will use a switch to generate the signal CLOCK.

Sequential Logic Section – Board Game Counter

a) Start the simulation.

b) Cycle the input CLOCK several times and record the value of the outputs A, B, and C in the table shown below.

*CLOCK*	A	B	C
Initial Values	0	0	1
1^st Toggle
2^nd Toggle
3^rd Toggle
4^th Toggle
5^th Toggle
6^st Toggle
7^th Toggle

c) Is the counter counting as expected (see below)? If not, check your circuit to make sure that it was built correctly. Make any necessary corrections and repeat steps (a) and (b).

d) Modify the circuit by replacing the input switch with a CLOCK_VOLTAGE set to 5 volts, 50% duty cycle @ 50 Hz (see below). The CLOCK_VOLTAGE will continuously toggle the input, causing the output to repeatedly cycle through the count 001 to 110.

Sequential Logic Section – Board Game Counter

a) Start the simulation.
b) Observe the outputs A, B, and C. They should be cycling through the following pattern:

c) Is the counter counting as expected? If not, check your circuit to make sure that it was built correctly. Make any necessary corrections and repeat steps (e) and (f).
Note: Do this assignment on paper, you won’t be able to enter in all of the data into the given space on this problem.

Finally, let’s connect the combinational and sequential logic sections together to complete the Board Game Counter.

a) Using the combinational logic and sequential logic sections created in problems 1 and 2, enter the circuit shown below into Multisim.

Combinational & Sequential Logic Section – Board Game Counter

b) Start the simulation.
c) Observe the outputs L1, L2, L3, L4, L5, L6, and L7. They should be cycling through the following pattern:

d) Are the outputs working as expected? If they are not, check your circuit to make sure that it was built correctly. Make any necessary corrections and repeat steps (b) and (c).