Notes 4

Question 1

Decimal

Answer 1

0-9 have numeric meaning
base 10
327 = 3x10^2 + 2x10^1 + 7x10^0

Question 2

Binary

Answer 2

only 0s and 1s have numeric meaning

base 2 system

Question 3

5 in binary

Answer 3

0101

Question 4

nibble

Answer 4

four bits

Question 5

byte

Answer 5

8 bits

Question 6

hexadecimal

Answer 6

0-F have numeric meaning
0-9 followed by A-F

Question 7

conversion from binary to decimal and vice versa

Answer 7

1 hex digit = 4 binary digits

Question 8

what is 01001100 in hexadecimal and decimal

Answer 8

hexadecimal:
0100 = 4
1100 = C
so 01001100 = 4C

decimal:
4+8+64 = 76

Question 9

half adder

Answer 9

adds two single bits
has a sum and a c out

Question 10

truth table of a half adder

Answer 10

A B | Cout Sum
0 0 0 0
0 1 0 1
1 0 0 1
1 1 1 0

Cout = AB
Sum - A xor B

Question 11

Block Diagrams

Answer 11

top and left are inputs
right is output
bottom can be either but never both

practice drawing some

Question 12

full adder

Answer 12

adds three bits
takes a A B and a C in and outputs a Cout and Sim

Question 13

full adder truth table

Answer 13

A B Cin | cout sum
0 0 0 0 0
0 0 1 0 1
0 1 0 0 1
0 1 1 1 0
1 0 0 0 1
1 0 1 1 0
1 1 0 1 0
1 1 1 1 1

sum = A xor B xor C
cout = AC + BC + AB

Question 14

practice drawing a full adder from two half adders and the block diagram for a full adder

Question 15

how to make an adder for two fout -bit number

Answer 15

4 bit ripple carry adder
Cin 0
Practice drawing it and the block diagram

Question 16

Bus notation

Answer 16

4
A ————–/—————

represents four bits from A

Question 17

how do you know if a number is negative as a signed number

Answer 17

begins with a 1

Question 18

how to make a number negative

Answer 18

flips the bits and add a 1

Question 19

subtracting is adding a ________ number

Answer 19

negative

Question 20

adder -subtracter block diagram

Answer 20

practice drawing