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8 XOR
XOR XNOR AND-OR-INV (Parity) : BCD, Excess-3 Gray
: Wakerly 5.8.1, 5.8.2, 5.8.3, 5.9, 5.9.1, 2.10, 2.11, 2.15.1, 5.4.8
Mano 1.7, 3.8, 3.9, 4.8
= +
EXCLUSIVE-OR (XOR)X Y XY0 0 0 0 1 11 0 11 1 0
1 10
X
AND-OR
X
NAND
X(X+Y)+Y(X+Y) =XX++YX+Y = + =
() = +
EXCLUSIVE-NOR (XNOR)
X Y (XY)0 0 10 1 01 0 0 1 1 1
()100
X
()
AND-OR
OR & XNORX
()
AND-OR
X
()
AND/NOR
X
()
X
()
NAND/OR
XOR & XNOR
0 = 1 = X = 0 X = 1 Y = Y = ( ) Y = ( )
Y = Y X( Y) Z = (Y Z) = Y Z
XOR & XNOR
()
()
()
()
Z = Z + Z + Z + Z
XOR 3
()Z10
X
Z
AND-OR
01
010
101
00 01 11 100
1
1 10Z
Z
(Z) = Z + Z + Z + Z
XNOR 3
(()Z)10
X
(Z)
AND-OR
01
010
101
00 01 11 100
1
1 00Z
Z
AND-OR-INVAND-OR-INV:
NAND
X
Z
Z
AND-OR-INV
X
(Z)
Z
AND-OR-INV
NAND
(Parity Code)
0101
000001010011100101
PoddXYZ
01
10
110111
1010
000001010011100101
PevenXYZ
10
01
110111
, (parity bit) ,
1
Z
..P
0
Z
..
(odd parity) m : 1, 1 0, 1
m-1 R
10 1
0Z
1
W 0
1
10 1
0Z1
W 0 0 m=4
ODD ODD
(even parity) m : 1, 1 0, 1
m-2 R 1 XNOR ( )
10
1
0Z
1
W 1
1
10 1
0Z1
W 1 1 m=4
EVEN EVEN
(m ) : 0,
(. 1) 1,
(. 1) ( m-2 R 1 R). ( = 1) .
m=4
10
1
0Z
1
Podd1
1
10 1
0ZPodd
0 0
0
EVEN EVEN
10 1
0Z
1
Peven0
1
10 1
0Z0
Peven1 1
(m ) : 0,
(. 1) 1,
(. 1) ( m-1
R). ( = 1) .
m=4
ODD ODD
Podd m-1 ( m-3 R 1 XNOR),
m 0
100Z
0 Podd0
00 0
0Z0 0
1 PoddEVEN
EVEN
3 4 , 3 0.
Peven m-1 ( m-2 R)
m 0
000Z
0 Peven0
00 0
0Z0 0
0PevenODD
ODD
3 4 , 3 0.
MSI : 74x280 & 9
8
9
10
11
12
13
1
2
4
5
6EVEN
ODD
MSI : 74x280 & 9
8
9
10
11
12
13
1
2
4
5
6
5 AND-OR-INV
BUFFEREDINPUTS
2 = (A1,A0) = (1,0) = , 1 = 1, 0 = 0
F(A=B) = (A1B1)y(A0B0)= (A1B1+A1B1)y(A0B0+A0B0) = A1B1(A0B0+A0B0) + A1B1(A0B0+A0B0) = A1A0B1B0 + A1A0B1B0 + A1A0B1B0 + A1A0B1B0*
> , 1 = 1, 1 = 0 1 = 1, 0 = 1, 0 = 0 F(A>B) = A1B1 + (A1B1)yA0B0
= A1B1 + A0B1B0 + A1A0B0* ( )
< , 1 = 0, 1 = 1 1 = 1, 0 = 0, 0 = 1 F(A
4 (=)
= (A3,A2,A1,A0) = (3,2,1,0)
=, 3=3, 2=2, 1=1, 0=0 F(A=B) = (A3B3)y(A2B2)y(A1B1)y(A0B0)
4 (>)
= (A3,A2,A1,A0) = (3,2,1,0)
A>B, 3=1, 3=0 3=3, 2=1, 2=0 3=3, 2=2, 1=1,1=0 3=3, 2=2, 1=1, 0=1,0=0
F(A>B) = A3B3+(A3B3)A2B2+(A3B3)(A2B2)A1B1+(A3B3)(A2B2)(A1B1)A0B0
4
3
3
2
2
1
1
0
0 F(A=B)
F(AB)
BCD(Binary-Coded-Decimal)
2345
6000000010010001101000101
89
0110011110001001
=10 BCD
10
7
=10 BCD
15
1 1 1 1
0 1 0 1 BCD0 0 0 1
BCD 4 0 9. BCD 8-4-2-1
1 5
Excess-3
2345
6001101000101011001111000
89
1001101010111100
=10 Exc-3
10
7
=10 Exc-3
15
1 1 1 1
1 0 0 0 Excess-30 1 0 0
Excess-3 4 0 9. BCD 3.
- 9 1 0 0 1.
1 5
8.1
BCD excess-3 : =(,B,C,D) : E=(W,X,Y,Z)
A={0,1,..,8,9}E={3,4,..,11,12}
E=A+3
AND-OR, OR-AND, NAND-NAND NOR-NOR 2
8.2
1 BCD, BCD+1
: BCD = (D0,C0,B0,A0) : BCD+1mod10 = (D1,C1,B1,A1)
BCD = {0,1,..,8,9}BCD+1mod10 ={1,2,..,9,0}
AND-OR, OR-AND, NAND-NAND NOR-NOR 2
8.3
()
BCD (segment).
F BE C
G
D
GrayGrayg2 g1 g0
23456
000001011010110111101
000001010011100101110
=10
10
7 100111
=2b2 b1 b0
Gray 3 (g2,g1,g0) 3 (b2,b1,b0) :- b1=b0, g0=0, g0=1.
- b2=b1, g1=0, g1=1.
- g2=b2 Gray . Gray .
Gray
2
001 011
001 010
=10
Gray
1
ADCs, , 1.
.
000, 011
:
8.4
Gray.
Gray .( 4 )
XOR
8.5
BCD Gray. XOR,
.
8.3