文档介绍：Flip-flops
Chapter4
Transformation between different flip-flops
Add the certain combinational logic circuit to the input of the original flip-flop
Original flip-flop
Converting circuit
Q’
Q
New flip-flop
New excitation input
Simultaneous characteristic equation
Original flip-flop
Converting circuit
Q’
Q
converted flip-flop
X, Q
Y
Yi=Fi(X,Q)
X be the input variable set of the new flip-flop
Y be the input variable set of the original flip-flop
Q be the present-state of the original flip-flop
Original flip-flop
Converting circuit
Q’
Q
converted flip-flop
X, Q
Y
Convert JK to D, T, RS
JK >> D
J=f1(D,Q), K=f2(D,Q)
Qn+1=D=DQ’+DQ
Qn+1=JQ’+K’Q
J=D, K=D’
JK >> T
J=f1(T,Q), K=f2(T,Q)
Qn+1=TQ’+T’Q
Qn+1=JQ’+K’Q
J=T, K=T
J
K
Q’
Q
C
D
J
K
Q’
Q
C
T
Convert JK to D, T, RS
JK >> RS
J=f1(R,S,Q), K=f2(R,S,Q)
Qn+1=S+R’Q (RS=0)
=S(Q’+Q)+R’Q
=SQ’+R’Q+SQ(R+R’)
=SQ’+R’Q+SR’Q
=SQ’+R’Q
J=S, K=Q
J
K
Q’
Q
C
R
S
Convert D to JK, T, RS
D >> JK
D=f1(J,K,Q)
Qn+1=JQ’+K’Q
Qn+1=D
D=JQ’+K’Q
D >> RS
D=f1(R,S,Q)
Qn+1=S+R’Q
Qn+1=D
D=S+R’Q
D
Q’
Q
C
K
J
D
Q’
Q
C
S
R
Simultaneous excitation table
0
0
1
1
d
1
0
0
0
0
1
d
Qn+1 Qn R S J K T D
0
1
0
1
0
d
1
d
d
1
d
0
0
0
1
1
0
1
1
0
T >> RS
0
0
1
1
d
1
0
0
0
0
1
d
Qn+1 Qn R S J K T D
0
1
0
1
0
d
1
d
d
1
d
0
0
0
1
1
0
1
1
0
00
01
11
10
0
1
0
1
2
3
6
7
4
5
RS
Q
1
1
d
d
T=SQ’+RQ
T =f(Q,R,S)
T >>D
0
1
0
1
0
1
2
3
D
Q
1
1
T=DQ’+D’Q
T =f(Q,D)
0
0
1
1
d
1
0
0
0
0
1
d
Qn+1 Qn R S J K D T
0
1
0
1
0
d
1
d
d
1
d
0
0
0
1
1
0
1
1
0