Monday, February 26

- ASCII and UNICODE (page 141)

- quick conversion: binary <==> octal <==> hexadecimal

dec.  bin.   hex.
-----------------
0     0000    0
1     0001    1
2     0010    2
3     0011    3
4     0100    4
5     0101    5
6     0110    6
7     0111    7
8     1000    8
9     1001    9
10    1010    A
11    1011    B
12    1100    C
13    1101    D
14    1110    E
15    1111    F

convert 742 decimal to binary, hex, and octal
   742 = 1011100110 binary  (repeated division algorithm)
       = 10 1110 0110       (group into 4's)
       = 2E6 hex            (using table above)
       = 1 011 100 110      (regroup into 3's)
       = 1346 octal         (using table)

convert 2BAD hex to binary and octal
   2BAD = 10101110101101 binary  (using table)
        = 10 101 110 101 101     (group into 3's)
        = 35656 octal            (using table)

convert A70F hex to binary and octal
  A70F = 1010 0111 0000 1111 binary  (using table)
       = 1 010 011 100 001 111       (regroup into 3's)
       = 123417 octal                (using table)

convert 765 octal to binary and hex
  765 = 111 110 101 binary  (using table)
      = 1 1111 0101         (regroup into 4's)
      = 1F5 hex             (using table)

------------------------------------------------------------
draw circuits for the following expressions:

 NOT ((NOT a) OR (NOT b))

 (a OR b) AND ((NOT c) OR (NOT d))

------------------------------------------------------------
circuit construction algorithm:

  - XOR truth table

  - Output-2 column of truth table on page 166

  - 1-bit addition circuit: sum and carryOut

------------------------------------------------------------
constructing a 4-bit addition circuit from 4 full-adders

truth table for full-adder (FA) circuit:

Cin  In1  In2      Sum    Cout
0    0    0        0      0
0    0    1        1      0
0    1    0        1      0
0    1    1        0      1
1    0    0        1      0
1    0    1        0      1
1    1    0        0      1
1    1    1        1      1

  a3 a2 a3 a0
+ b3 b2 b1 b0
-------------
C s3 s2 s1 s0  (C is final carry-out)

                  +----------+
              0 --|Cin    Sum|------- s0 (least significant bit)
                  |    FA    |
        a0 -------|In1       |
        b0 -------|In2   Cout|---+
                  +----------+   |
                                 |
              +------------------+
              |
              |   +----------+
              +---|Cin    Sum|------- s1
                  |    FA    |
        a1 -------|In1       |
        b1 -------|In2   Cout|---+
                  +----------+   |
                                 |
              +------------------+
              |
              |   +----------+
              +---|Cin    Sum|------- s2
                  |    FA    |
        a2 -------|In1       |
        b2 -------|In2   Cout|---+
                  +----------+   |
                                 |
              +------------------+
              |
              |   +----------+
              +---|Cin    Sum|------- s3
                  |    FA    |
        a3 -------|In1       |
        b3 -------|In2   Cout|------- carry-out
                  +----------+