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Ενότητα 8 Η ΠΥΛΗ XOR ΚΑΙ ΟΙ ΕΦΑΡΜΟΓΕΣ ΤΗΣ ΚΩΔΙΚΟΠΟΙΗΣΗ

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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 (
  • 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