## Objectives of this lab:

```
To investigate flip-flop characteristics.
To verify sequential design procedures by building a simple counter.

```

## Preparation

```
Read lab lecture notes which contains the Sequential Design Procedure.

```

## Lab Assignments

1. Implement the following circuit to test the characteristics of a D flip flop.
• Note:
• Using a clock input to operate the flip-flop is rather quickly.
• You may wish to select the slow motion of the clock OR
to use a simple binary switch instead of a clock input device.
• Verify the flip flop state table.

• Questions:
• Is a D flip-flop positive or negative edge triggered?________
• What happens when the Set switch is set to zero?__________
• What happens when the Reset switch is set to zero?_________
• Does it matter what the D input is when either Set or Reset is zero?_________

2. Experimentally verify the JK flip-flop state table with the following circuit.
Is the JK flip-flop positive or negative edge triggered?________
Verify the excitation table.

Reference

```
Characteristic Table                    Excitation Table
==========================            ===================
J  K  Q(t+1)  Operation               Q(t)  Q(t+1)  J  K
==========================            ===================
0  0  Q(t)    No Change               0     0       0  x
--------------------------            -------------------
0  1  0       Reset                   0     1       1  x
--------------------------            -------------------
1  0  1       Set                     1     0       x  1
--------------------------            -------------------
1  1  Q'(t)   Complement              1     1       x  0
==========================            ===================

```
3. Design a 3 bit counter which follows the sequence 0 -> 2 -> 3 -> 4 -> 7 -> 0.
Note: The following are required for the lab Assignment:
• Follow the sequential design procedure which is presented in the lab lecture notes.
• To make marking easier, route all the unused states to state 7.
• Use JK flip-flops in your counter circuits.
Hand in:
• Show your design steps and the resulting circuits in LogicWorks 5.