Flip-Flops and Related Devices
387
(a)
J
Q
Q
K
Clk
CLEAR
PRESET
Q
K
J
Clk
FF
Pr
Cl
(b)
PR
0
1
0
1
1
1
1
1
CL
1
0
0
1
1
1
1
1
CLK
X
X
X
1
1
1
1
0
J
X
X
X
0
1
0
1
X
K
X
X
X
0
0
1
1
X
Q n+1
1
0
--Q n
1
0
Q n
Q n+1
0
1
--0
1
Q n
Q n
Toggle
(c)
Q
—
Figure 10.29 J -K flip-flop with PRESET and CLEAR inputs.