Sequential Circuits & Flip-Flops
RS flip-flop
|
S |
R |
Q(t+1) |
Comments |
|
0 |
0 |
Q(t) |
no change |
|
0 |
1 |
0 |
clear |
|
1 |
0 |
1 |
set |
|
1 |
1 |
? |
not allowed |
RS Characteristic Table
D or data flip-flop is a modification of the RS flip-flop
(inverter is inserted between S and R and send in D to the S input)
|
D |
Q(t+1) |
Comments |
|
0 |
0 |
Clear |
|
1 |
1 |
Set |
D Characteristic table
JK flip-flop is a refinement of the RS flip-flop
in that the indeterminate condition of the RS flip-flop is defined in the JK type
|
J |
K |
Q(t+1) |
Comments |
|
0 |
0 |
Q(t) |
no change |
|
0 |
1 |
0 |
clear |
|
1 |
0 |
1 |
set |
|
1 |
1 |
Q’(t) |
complement |
JK Characteristic Table
T flip-flop is a refinement of the JK flip-flop
in that the inputs J and K are tied together.
|
T |
Q(t+1) |
Comments |
|
0 |
Q(t) |
Clear |
|
1 |
Q’(t) |
Set |
T Characteristic table
Excitation Tables for the Four types of Flip-Flops
RS flip-flop
|
Q(t) |
Q(t+1) |
S |
R |
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JK flip-flop
|
Q(t) |
Q(t+1) |
J |
K |
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D flip-flop
|
Q(t) |
Q(t+1) |
D |
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T flip-flop
|
Q(t) |
Q(t+1) |
T |
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Excitation Tables for the Four
types of Flip-Flops
RS flip-flop
|
Q(t) |
Q(t+1) |
S |
R |
|
0 |
0 |
0 0 0 |
0 1 X |
|
0 |
1 |
1 |
0 |
|
1 |
0 |
0 |
1 |
|
1 |
1 |
1 0 X |
0 0 0 |
JK flip-flop
|
Q(t) |
Q(t+1) |
J |
K |
|
0 |
0 |
0 0 0 |
0 1 X |
|
0 |
1 |
1 1 1 |
0 1 X |
|
1 |
0 |
0 1 X |
1 1 1 |
|
1 |
1 |
0 1 X |
0 0 0 |
D flip-flop
|
Q(t) |
Q(t+1) |
D |
|
0 |
0 |
0 |
|
0 |
1 |
1 |
|
1 |
0 |
0 |
|
1 |
1 |
1 |
T flip-flop
|
Q(t) |
Q(t+1) |
T |
|
0 |
0 |
0 |
|
0 |
1 |
1 |
|
1 |
0 |
1 |
|
1 |
1 |
0 |
The rest of the material was on handouts.