TABLE OF CONTENTS By modifying the inputs of a particular type of a flip flop, we can be converted it to another type. The following example illustrates the procedure.
Construct a clocked JK flip flop which is triggered at the positive edge of the clock pulse from a:
clocked SR flip flop consisting of NOR gates
clocked T flip flop
clocked D flip flop
Solution:
We must determine how the inputs of the given flip flop must be modified so that it will behave as a JK flip flop. We begin with the construction of the transition tables shown in Table 8.6 where X denotes a don't care condition.
| Flip Flop Type | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| SR | JK | D | T | ||||||||||
| Q n | Q n+1 | S | R | Q n | Q n+1 | J | K | Q n | Q n+1 | D | Q n | Q n+1 | T |
| 0 | 0 | 0 | X | 0 | 0 | 0 | X | 0 | 0 | 0 | 0 | 0 | 0 |
| 0 | 1 | 1 | 0 | 0 | 1 | 1 | X | 0 | 1 | 1 | 0 | 1 | 1 |
| 1 | 0 | 0 | 1 | 1 | 0 | X | 1 | 1 | 0 | 0 | 1 | 0 | 1 |
| 1 | 1 | X | 0 | 1 | 1 | X | 0 | 1 | 1 | 1 | 1 | 1 | 0 |
From the transition table of Table 8.6 we add Columns (1), (2), and (3) to the characteristic table of the JK flip flop as shown in Table 8.7.
