chapter 1b1morris/cpe100/fa17/slides/ddca... · • convert 2910 to octal • method 2 29/8 =3 r5...
TRANSCRIPT
![Page 1: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/1.jpg)
Chapter 1 <1>
Professor Brendan Morris, SEB 3216, [email protected] http://www.ee.unlv.edu/~b1morris/cpe100/
Chapter 1
CPE100: Digital Logic Design I
Section 1004: Dr. Morris
From Zero to One
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Chapter 1 <2>
Background: Digital Logic Design
• How have digital devices changed the world?
• How have digital devices changed your life?
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Chapter 1 <3>
Background
• Digital Devices have revolutionized our world • Internet, cell phones, rapid advances in medicine, etc.
• The semiconductor industry has grown from $21 billion in 1985 to over $300 billion in 2015
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Chapter 1 <4>
The Game Plan
• Purpose of course:
• Learn the principles of digital design
• Learn to systematically debug increasingly complex designs
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Chapter 1 <5>
Chapter 1: Topics
• The Art of Managing Complexity
• The Digital Abstraction
• Number Systems
• Addition
• Binary Codes
• Signed Numbers
• Logic Gates
• Logic Levels
• CMOS Transistors
• Power Consumption
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Chapter 1 <6>
The Art of Managing Complexity
• Abstraction
• Discipline
• The Three –y’s
• Hierarchy
• Modularity
• Regularity
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Chapter 1 <7>
Abstraction
• What is abstraction?
• Hiding details when they are not important
• Electronic computer abstraction
• Different levels with different building blocks
focu
s o
f th
is c
ou
rse
programs
device drivers
instructions
registers
datapaths
controllers
adders
memories
AND gates
NOT gates
amplifiers
filters
transistors
diodes
electrons
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Chapter 1 <8>
Discipline
• Intentionally restrict design choices
• Example: Digital discipline
– Discrete voltages (0 V, 5 V) instead of continuous
(0V – 5V)
– Simpler to design than analog circuits – can build
more sophisticated systems
– Digital systems replacing analog predecessors:
• i.e., digital cameras, digital television, cell phones,
CDs
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Chapter 1 <9>
The Three –y’s
• Hierarchy
• A system divided into modules and submodules
• Modularity
• Having well-defined functions and interfaces
• Regularity
• Encouraging uniformity, so modules can be easily
reused
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Chapter 1 <10>
Example: Flintlock Rifle
• Hierarchy
• Three main modules: Lock, stock, and barrel
• Submodules of lock: Hammer, flint, frizzen, etc.
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Chapter 1 <11>
Example Flintlock Rifle
• Modularity
• Function of stock: mount barrel and lock
• Interface of stock: length and location of mounting pins
• Regularity
• Interchangeable parts
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Chapter 1 <12>
The Art of Managing Complexity
• Abstraction
• Discipline
• The Three –y’s
• Hierarchy
• Modularity
• Regularity
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Chapter 1 <13>
The Digital Abstraction
• Most physical variables are continuous
• Voltage on a wire (1.33 V, 9 V, 12.2 V)
• Frequency of an oscillation (60 Hz, 33.3 Hz, 44.1 kHz)
• Position of mass (0.25 m, 3.2 m)
• Digital abstraction considers discrete subset of values
• 0 V, 5 V
• “0”, “1”
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Chapter 1 <14>
The Analytical Engine
• Designed by Charles Babbage from 1834 – 1871
• Considered to be the first digital computer
• Built from mechanical gears, where each gear represented a discrete value (0-9)
• Babbage died before it was finished
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Chapter 1 <15>
Digital Discipline: Binary Values
• Two discrete values
• 1 and 0
• 1 = TRUE = HIGH = ON
• 0 = FALSE = LOW = OFF
• How to represent 1 and 0
• Voltage levels, rotating gears, fluid levels, etc.
• Digital circuits use voltage levels to represent 1 and 0
• Bit = binary digit
• Represents the status of a digital signal (2 values)
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Chapter 1 <16>
Why Digital Systems?
• Easier to design
• Fast
• Can overcome noise
• Error detection/correction
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Chapter 1 <17>
George Boole, 1815-1864
• Born to working class parents
• Taught himself mathematics and joined the faculty of Queen’s College in Ireland
• Wrote An Investigation of the Laws of Thought (1854)
• Introduced binary variables
• Introduced the three fundamental logic operations: AND, OR, and NOT
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Chapter 1 <18>
Number Systems
• Decimal
• Base 10
• Binary
• Base 2
• Hexadecimal
• Base 16
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Chapter 1 <19>
Decimal Numbers
• Base 10 (our everyday number system)
537410 = 5 × 103 + 3 × 102 + 7 × 101 + 4 × 100
1’s C
olu
mn
1
0’s C
olu
mn
1
00
’s Co
lum
n
10
00
’s Co
lum
n
Five Thousand
Three Hundred
Seven Tens
Four Ones
Base 10
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Chapter 1 <20>
Binary Numbers
• Base 2 (computer number system)
11012 = 1 × 23 + 1 × 22 + 0 × 21 + 1 × 20
1’s C
olu
mn
2
’s Co
lum
n
4’s C
olu
mn
8
’s Co
lum
n
One Eight
One Four
Zero Two
One One
Base 2
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Chapter 1 <21>
Powers of Two
• 20 =
• 21 =
• 22 =
• 23 =
• 24 =
• 25 =
• 26 =
• 27 =
• 28 =
• 29 =
• 210 =
• 211 =
• 212 =
• 213 =
• 214 =
• 215 =
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Chapter 1 <22>
Powers of Two
• 20 = 1
• 21 = 2
• 22 = 4
• 23 = 8
• 24 = 16
• 25 = 32
• 26 = 64
• 27 = 128
• Handy to memorize up to 210
• 28 = 256
• 29 = 512
• 210 = 1024
• 211 = 2048
• 212 = 4096
• 213 = 8192
• 214 = 16384
• 215 = 32768
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Chapter 1 <23>
Bits, Bytes, Nibbles …
• Bits
• Bytes = 8 bits
• Nibble = 4 bits
• Words = 32 bits
• Hex digit to represent nibble
10010110least
significant
bit
most
significant
bit
10010110nibble
byte
CEBF9AD7least
significant
byte
most
significant
byte
![Page 24: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/24.jpg)
Chapter 1 <24>
Decimal to Binary Conversion
• Two Methods:
• Method 1: Find largest power of 2 that fits, subtract and repeat
• Method 2: Repeatedly divide by 2, remainder goes in next most significant bit
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Chapter 1 <25>
D2B: Method 1
• Find largest power of 2 that fits, subtract, repeat
5310
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Chapter 1 <26>
D2B: Method 1
• Find largest power of 2 that fits, subtract, repeat
5310 5310 32×1
53-32 = 21 16×1
21-16 = 5 4×1
5-4 = 1 1×1
5310 32×1
53-32 = 21
5310 32×1
53-32 = 21 16×1
21-16 = 5
5310 32×1
53-32 = 21 16×1
21-16 = 5 4×1
5-4 = 1
= 1101012
![Page 27: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/27.jpg)
Chapter 1 <27>
D2B: Method 2
• Repeatedly divide by 2, remainder goes in next most significant bit
5310 =
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Chapter 1 <28>
D2B: Method 2
• Repeatedly divide by 2, remainder goes in next most significant bit
5310 = 5310 = 53/2 = 26 R1
5310 = 53/2 = 26 R1
26/2 = 13 R0
5310 = 53/2 = 26 R1
26/2 = 13 R0
13/2 = 6 R1
5310 = 53/2 = 26 R1
26/2 = 13 R0
13/2 = 6 R1
6/2 = 3 R0
5310 = 53/2 = 26 R1
26/2 = 13 R0
13/2 = 6 R1
6/2 = 3 R0
3/2 = 1 R1
5310 = 53/2 = 26 R1
26/2 = 13 R0
13/2 = 6 R1
6/2 = 3 R0
3/2 = 1 R1
1/2 = 0 R1
= 1101012
LSB
MSB
![Page 29: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/29.jpg)
Chapter 1 <29>
Number Conversion
• Binary to decimal conversion
• Convert 100112 to decimal
• Decimal to binary conversion
• Convert 4710 to binary
32 × 1 + 16 × 0 + 8 × 1 + 4 × 1 + 2 × 1 + 1 × 1 = 1011112
16 × 1 + 8 × 0 + 4 × 0 + 2 × 1 + 1 × 1 = 1910
![Page 30: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/30.jpg)
Chapter 1 <30>
D2B Example
• Convert 7510 to binary
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Chapter 1 <31>
D2B Example
• Convert 7510 to binary
• Or
7510= 64 + 8 + 2 + 1 = 10010112
75/2 = 37 R1
37/2 = 18 R1
18/2 = 9 R0
9/2 = 4 R1
4/2 = 2 R0
2/2 = 1 R0
1/2 = 0 R1
![Page 32: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/32.jpg)
Chapter 1 <32>
Binary Values and Range
• N-digit decimal number
• How many values?
• Range?
• Example: 3-digit decimal number
• Possible values
• Range
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Chapter 1 <33>
Binary Values and Range
• N-digit decimal number
• How many values? • 10𝑁
• Range? • [0, 10𝑁 − 1]
• Example: 3-digit decimal number
• Possible values • 103 = 1000
• Range • [0, 999]
![Page 34: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/34.jpg)
Chapter 1 <34>
Binary Values and Range
• N-bit binary number
• How many values?
• Range?
• Example: 3-bit binary number
• Possible values
• Range
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Chapter 1 <35>
Binary Values and Range
• N-bit binary number
• How many values? • 2𝑁
• Range? • [0, 2𝑁 − 1]
• Example: 3-bit binary number
• Possible values • 23 = 8
• Range • 0, 7 = [0002, 1112]
![Page 36: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/36.jpg)
Chapter 1 <36>
Binary Values and Range
• N-digit decimal number
• How many values?
• 10𝑁
• Range?
• [0, 10𝑁 − 1]
• Example: 3-digit decimal number
• Possible values
• 103 = 1000
• Range
• [0, 999]
• N-bit binary number
• How many values?
• 2𝑁
• Range?
• [0, 2𝑁 − 1]
• Example: 3-bit binary number
• Possible values
• 23 = 8
• Range
• 0, 7 = [0002, 1112]
![Page 37: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/37.jpg)
Chapter 1 <37>
Hexadecimal Numbers
• Base 16 number system
• Shorthand for binary
• Four binary digits (4-bit binary number) is a single hex digit
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Chapter 1 <38>
Hexadecimal Numbers
Hex Digit Decimal Equivalent Binary Equivalent
0 0
1 1
2 2
3 3
4 4
5 5
6 6
7 7
8 8
9 9
A 10
B 11
C 12
D 13
E 14
F 15
![Page 39: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/39.jpg)
Chapter 1 <39>
Hexadecimal Numbers
Hex Digit Decimal Equivalent Binary Equivalent
0 0 0000
1 1 0001
2 2 0010
3 3 0011
4 4 0100
5 5 0101
6 6 0110
7 7 0111
8 8 1000
9 9 1001
A 10 1010
B 11 1011
C 12 1100
D 13 1101
E 14 1110
F 15 1111
![Page 40: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/40.jpg)
Chapter 1 <40>
Hexadecimal to Binary Conversion
• Hexadecimal to binary conversion:
• Convert 4AF16 (also written 0x4AF) to binary
• Hexadecimal to decimal conversion:
• Convert 0x4AF to decimal
![Page 41: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/41.jpg)
Chapter 1 <41>
Hexadecimal to Binary Conversion
• Hexadecimal to binary conversion:
• Convert 4AF16 (also written 0x4AF) to binary
• 0x4AF = 0100 1010 11112
• Hexadecimal to decimal conversion:
• Convert 0x4AF to decimal
• 4 × 162 + 10 × 161 + 15 × 160 = 119910
![Page 42: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/42.jpg)
Chapter 1 <42>
Number Systems
• Popular
• Decima l Base 10
• Binary Base 2
• Hexadecimal Base 16
• Others
• Octal Base 8
• Any other base
![Page 43: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/43.jpg)
Chapter 1 <43>
Octal Numbers
• Same as hex with one less binary digit
Octal Digit Decimal Equivalent Binary Equivalent
0 0 000
1 1 001
2 2 010
3 3 011
4 4 100
5 5 101
6 6 110
7 7 111
![Page 44: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/44.jpg)
Chapter 1 <44>
Number Systems
• In general, an N-digit number {𝑎𝑁−1𝑎𝑁−2 … 𝑎1𝑎0} of base 𝑅 in decimal equals
• 𝑎𝑁−1𝑅𝑁−1 + 𝑎𝑁−2𝑅𝑁−2 + ⋯ + 𝑎1𝑅1 + 𝑎0𝑅0
• Example: 4-digit {5173} of base 8 (octal)
![Page 45: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/45.jpg)
Chapter 1 <45>
Number Systems
• In general, an N-digit number {𝑎𝑁−1𝑎𝑁−2 … 𝑎1𝑎0} of base 𝑅 in decimal equals
• 𝑎𝑁−1𝑅𝑁−1 + 𝑎𝑁−2𝑅𝑁−2 + ⋯ + 𝑎1𝑅1 + 𝑎0𝑅0
• Example: 4-digit {5173} of base 8 (octal)
• 5 × 83 + 1 × 82 + 7 × 81 + 3 × 80 = 268310
![Page 46: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/46.jpg)
Chapter 1 <46>
Decimal to Octal Conversion
• Remember two methods for D2B conversion
• 1: remove largest multiple; 2: repeated divide
• Convert 2910 to octal
![Page 47: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/47.jpg)
Chapter 1 <47>
Decimal to Octal Conversion
• Remember two methods for D2B conversion
• 1: remove largest multiple; 2: repeated divide
• Convert 2910 to octal
• Method 2
29/8 =3 R5 lsb 3/8 =0 R3 msb
2910 = 358
![Page 48: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/48.jpg)
Chapter 1 <48>
Decimal to Octal Conversion
• Remember two methods for D2B conversion
• 1: remove largest multiple; 2: repeated divide
• Convert 2910 to octal
• Method 1
• Or (better scalability)
29 8×3=24 29-24=5 2910 = 24 + 5 = 3 × 81 + 5 × 80 = 358
2910 = 16 + 8 + 4 + 1 = 111012 = 358
![Page 49: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/49.jpg)
Chapter 1 <49>
Octal to Decimal Conversion
• Convert 1638 to decimal
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Chapter 1 <50>
Octal to Decimal Conversion
• Convert 1638 to decimal
• 1638 = 1 × 82 + 6 × 81 + 3
• 1638 = 64 + 48 + 3
• 1638 = 11510
![Page 51: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/51.jpg)
Chapter 1 <51>
Recap: Binary and Hex Numbers
• Example 1: Convert 8310 to hex
• Example 2: Convert 011010112 to hex and decimal
• Example 3: Convert 0xCA3 to binary and decimal
![Page 52: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/52.jpg)
Chapter 1 <52>
Recap: Binary and Hex Numbers
• Example 1: Convert 8310 to hex
• 8310 = 64 + 16 + 2 + 1 = 10100112
• 10100112 = 101 00112 = 5316
• Example 2: Convert 011010112 to hex and decimal
• 011010112 = 0110 10112 = 6𝐵16
• 0x6B = 6 × 161 + 11 × 160 = 96 + 11 = 107
• Example 3: Convert 0xCA3 to binary and decimal
• 0xCA3 = 1100 1010 00112
• 0xCA3 = 12 × 162 + 10 × 161 + 3 × 160 = 323510
![Page 53: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/53.jpg)
Chapter 1 <53>
Large Powers of Two
• 210 = 1 kilo ≈ 1000 (1024)
• 220 = 1 mega ≈ 1 million (1,048,576)
• 230 = 1 giga ≈ 1 billion (1,073,741,824)
• 240 = 1 tera ≈ 1 trillion (1,099,511,627,776)
![Page 54: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/54.jpg)
Chapter 1 <54>
Large Powers of Two: Abbreviations
• 210 = 1 kilo ≈ 1000 (1024)
for example: 1 kB = 1024 Bytes
1 kb = 1024 bits
• 220 = 1 mega ≈ 1 million (1,048,576)
for example: 1 MiB, 1 Mib (1 megabit)
• 230 = 1 giga ≈ 1 billion (1,073,741,824)
for example: 1 GiB, 1 Gib
![Page 55: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/55.jpg)
Chapter 1 <55>
Estimating Powers of Two
• What is the value of 224?
• How many values can a 32-bit variable represent?
![Page 56: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/56.jpg)
Chapter 1 <56>
Estimating Powers of Two
• What is the value of 224?
• 24 × 220 ≈ 16 million
• How many values can a 32-bit variable represent?
• 22 × 230 ≈ 4 billion
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Chapter 1 <57>
Binary Codes
Another way of representing decimal numbers
Example binary codes:
• Weighted codes • Binary Coded Decimal (BCD) (8-4-2-1 code)
• 6-3-1-1 code
• 8-4-2-1 code (simple binary)
• Gray codes
• Excess-3 code
• 2-out-of-5 code
![Page 58: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/58.jpg)
Chapter 1 <58>
Binary Codes
Decimal # 8-4-2-1 (BCD)
6-3-1-1 Excess-3 2-out-of-5 Gray
0 0000 0000 0011 00011 0000
1 0001 0001 0100 00101 0001
2 0010 0011 0101 00110 0011
3 0011 0100 0110 01001 0010
4 0100 0101 0111 01010 0110
5 0101 0111 1000 01100 1110
6 0110 1000 1001 10001 1010
7 0111 1001 1010 10010 1011
8 1000 1011 1011 10100 1001
9 1001 1100 1100 11000 1000
Each code combination represents a single decimal digit.
![Page 59: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/59.jpg)
Chapter 1 <59>
Weighted Codes
• Weighted codes: each bit position has a given weight
• Binary Coded Decimal (BCD) (8-4-2-1 code)
• Example: 72610 = 0111 0010 0110BCD
• 6-3-1-1 code
• Example: 1001 (6-3-1-1 code) = 1×6 + 0×3 + 0×1 + 1×1
• Example: 72610 = 1001 0011 10006311
• BCD numbers are used to represent fractional numbers exactly (vs. floating point numbers – which can’t - see Chapter 5)
![Page 60: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/60.jpg)
Chapter 1 <60>
Weighted Codes
• BCD Example:
72610 = 0111 0010 0110BCD
• 6-3-1-1 code Example:
72610 = 1001 0011 10006311
Decimal # 8-4-2-1 (BCD)
6-3-1-1
0 0000 0000
1 0001 0001
2 0010 0011
3 0011 0100
4 0100 0101
5 0101 0111
6 0110 1000
7 0111 1001
8 1000 1011
9 1001 1100
![Page 61: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/61.jpg)
Chapter 1 <61>
Excess-3 Code
• Add 3 to number, then represent in binary • Example: 510 = 5+3 = 8 =
10002
• Also called a biased number
• Excess-3 codes (also called XS-3) were used in the 1970’s to ease arithmetic
• Excess-3 Example:
72610 = 1010 0101 1001xs3
Decimal # Excess-3
0 0011
1 0100
2 0101
3 0110
4 0111
5 1000
6 1001
7 1010
8 1011
9 1100
![Page 62: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/62.jpg)
Chapter 1 <62>
2-out-of-5 Code
• 2 out of the 5 bits are 1
• Used for error detection:
• If more or less than 2 of 5 bits are 1, error
Decimal # 2-out-of-5
0 00011
1 00101
2 00110
3 01001
4 01010
5 01100
6 10001
7 10010
8 10100
9 11000
![Page 63: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/63.jpg)
Chapter 1 <63>
Gray Codes
• Next number differs in only one bit position
• Example: 000, 001, 011, 010, 110, 111, 101, 100
• Example use: Analog-to-Digital (A/D) converters. Changing 2 bits at a time (i.e., 011 →100) could cause large inaccuracies.
Decimal # Gray
0 0000
1 0001
2 0011
3 0010
4 0110
5 1110
6 1010
7 1011
8 1001
9 1000
![Page 64: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/64.jpg)
Chapter 1 <64>
Addition
• Decimal
• Binary
37345168+
10110011+
![Page 65: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/65.jpg)
Chapter 1 <65>
• Decimal
• Binary
37345168+
8902
carries 11
10110011+
Addition
![Page 66: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/66.jpg)
Chapter 1 <66>
• Decimal
• Binary
37345168+
8902
carries 11
10110011+
1110
11 carries
Addition
![Page 67: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/67.jpg)
Chapter 1 <67>
Binary Addition Examples
• Add the following 4-bit
binary numbers
• Add the following 4-bit
binary numbers
10010101+
10110110+
![Page 68: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/68.jpg)
Chapter 1 <68>
Binary Addition Examples
• Add the following 4-bit
binary numbers
• Add the following 4-bit
binary numbers
10010101+
1110
1
10110110+
![Page 69: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/69.jpg)
Chapter 1 <69>
Binary Addition Examples
• Add the following 4-bit
binary numbers
• Add the following 4-bit
binary numbers
10010101+
1110
1
10110110+
10001
111
Overflow!
![Page 70: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/70.jpg)
Chapter 1 <70>
Overflow
• Digital systems operate on a fixed number of
bits
• Overflow: when result is too big to fit in the
available number of bits
• See previous example of 11 + 6
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Chapter 1 <71>
Signed Binary Numbers
• Sign/Magnitude Numbers
• Two’s Complement Numbers
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Chapter 1 <72>
Sign/Magnitude
• 1 sign bit, N-1 magnitude bits
• Sign bit is the most significant (left-most) bit
– Positive number: sign bit = 0
– Negative number: sign bit = 1
• Example, 4-bit sign/magnitude representations of ± 6:
• +6 =
• -6 =
• Range of an N-bit sign/magnitude number:
•
1
1 2 2 1 0
2
0
: , , , ,
( 1) 2n
N N
na i
i
i
A a a a a a
A a
![Page 73: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/73.jpg)
Chapter 1 <73>
Sign/Magnitude
• 1 sign bit, N-1 magnitude bits
• Sign bit is the most significant (left-most) bit
– Positive number: sign bit = 0
– Negative number: sign bit = 1
• Example, 4-bit sign/magnitude representations of ± 6:
• +6 = 0110
• -6 = 1110
• Range of an N-bit sign/magnitude number:
• [-(2N-1-1), 2N-1-1]
1
1 2 2 1 0
2
0
: , , , ,
( 1) 2n
N N
na i
i
i
A a a a a a
A a
![Page 74: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/74.jpg)
Chapter 1 <74>
Sign/Magnitude Numbers
• Problems:
• Addition doesn’t work, for example -6 + 6:
1110
+ 0110
• Two representations of 0 (± 0):
• +0 =
• −0 =
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Chapter 1 <75>
Sign/Magnitude Numbers
• Problems:
• Addition doesn’t work, for example -6 + 6:
1110
+ 0110
10100 (wrong!)
• Two representations of 0 (± 0):
• +0 = 0000
• −0 = 1000
![Page 76: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/76.jpg)
Chapter 1 <76>
Two’s Complement Numbers
• Don’t have same problems as sign/magnitude numbers:
• Addition works
• Single representation for 0
• Range of representable numbers not symmetric
• One extra negative number
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Chapter 1 <77>
Two’s Complement Numbers
• msb has value of −2𝑁−1
• The most significant bit still indicates the sign
(1 = negative, 0 = positive)
• Range of an N-bit two’s comp number?
• Most positive 4-bit number?
• Most negative 4-bit number?
2
1
1
0
2 2n
n i
n i
i
A a a
![Page 78: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/78.jpg)
Chapter 1 <78>
Two’s Complement Numbers
• msb has value of −2𝑁−1
• The most significant bit still indicates the sign
(1 = negative, 0 = positive)
• Range of an N-bit two’s comp number?
• [− 2𝑁−1 , 2N−1 − 1]
• Most positive 4-bit number?
• Most negative 4-bit number?
2
1
1
0
2 2n
n i
n i
i
A a a
0111
1000
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Chapter 1 <79>
“Taking the Two’s Complement”
• Flips the sign of a two’s complement
number
• Method: 1. Invert the bits
2. Add 1
• Example: Flip the sign of 310 = 00112
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Chapter 1 <80>
“Taking the Two’s Complement”
• Flips the sign of a two’s complement
number
• Method: 1. Invert the bits
2. Add 1
• Example: Flip the sign of 310 = 00112
1. 1100
2. + 1
1101 = -310
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Chapter 1 <81>
Two’s Complement Examples
• Take the two’s complement of 610 = 01102
• What is the decimal value of the two’s
complement number 10012?
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Chapter 1 <82>
Two’s Complement Examples
• Take the two’s complement of 610 = 01102
1. 1001
2. + 1
10102 = -610
• What is the decimal value of the two’s
complement number 10012? 1. 0110
2. + 1
01112 = 710, so 10012 = -710
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Chapter 1 <83>
Two’s Complement Addition
• Add 6 + (-6) using two’s complement
numbers
• Add -2 + 3 using two’s complement numbers
+11100011
+01101010
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Chapter 1 <84>
Two’s Complement Addition
• Add 6 + (-6) using two’s complement
numbers
• Add -2 + 3 using two’s complement numbers
+01101010
10000
111
+11100011
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Chapter 1 <85>
Two’s Complement Addition
• Add 6 + (-6) using two’s complement
numbers
• Add -2 + 3 using two’s complement numbers
+11100011
10001
111
+01101010
10000
111
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Chapter 1 <86>
Increasing Bit Width
• Extend number from N to M bits (M > N) :
• Sign-extension
• Zero-extension
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Chapter 1 <87>
Sign-Extension
• Sign bit copied to msb’s
• Number value is same
• Example 1
• 4-bit representation of 3 = 0011
• 8-bit sign-extended value:
• Example 2
• 4-bit representation of -7 = 1001
• 8-bit sign-extended value:
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Chapter 1 <88>
Sign-Extension
• Sign bit copied to msb’s
• Number value is same
• Example 1
• 4-bit representation of 3 = 0011
• 8-bit sign-extended value: 00000011
• Example 2
• 4-bit representation of -7 = 1001
• 8-bit sign-extended value: 11111001
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Chapter 1 <89>
Zero-Extension
• Zeros copied to msb’s
• Value changes for negative numbers
• Example 1
• 4-bit value = 00112 • 8-bit zero-extended value:
• Example 2
• 4-bit value = 1001 • 8-bit zero-extended value:
![Page 90: Chapter 1b1morris/cpe100/fa17/slides/DDCA... · • Convert 2910 to octal • Method 2 29/8 =3 R5 lsb 3/8 =0 R3 msb 2910=358. Chapter 1 Decimal to Octal Conversion](https://reader030.vdocuments.net/reader030/viewer/2022040514/5e6c27ec08fa3e72a23f5f74/html5/thumbnails/90.jpg)
Chapter 1 <90>
Zero-Extension
• Zeros copied to msb’s
• Value changes for negative numbers
• Example 1
• 4-bit value = 00112 • 8-bit zero-extended value: 00000011
• Example 2
• 4-bit value = 1001 • 8-bit zero-extended value: 00001001
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Chapter 1 <91>
Zero-Extension
• Zeros copied to msb’s
• Value changes for negative numbers
• Example 1
• 4-bit value = 00112 = 310
• 8-bit zero-extended value: 00000011 = 310
• Example 2
• 4-bit value = 1001 = -710
• 8-bit zero-extended value: 00001001 = 910
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Chapter 1 <92>
Number System Comparison
-8
1000 1001
-7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
1010 1011 1100 1101 1110 1111 0000 0001 0010 0011 0100 0101 0110 0111 Two's Complement
10001001101010111100110111101111
00000001 0010 0011 0100 0101 0110 0111
1000 1001 1010 1011 1100 1101 1110 11110000 0001 0010 0011 0100 0101 0110 0111
Sign/Magnitude
Unsigned
Number System Range
Unsigned [0, 2N-1]
Sign/Magnitude [-(2N-1-1), 2N-1-1]
Two’s Complement [-2N-1, 2N-1-1]
For example, 4-bit representation:
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Chapter 1 <93>
Logic Gates
• Perform logic functions:
• inversion (NOT), AND, OR, NAND, NOR, etc.
• Single-input:
• NOT gate, buffer
• Two-input:
• AND, OR, XOR, NAND, NOR, XNOR
• Multiple-input
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Chapter 1 <94>
Single-Input Logic Gates
NOT
Y = A
A Y0
1
A Y
BUF
Y = A
A Y0
1
A Y
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Chapter 1 <95>
Single-Input Logic Gates
• Bubble on wire indicates inversion
• Note: bar over variable indicates complement (invert value)
NOT
Y = A
A Y0 1
1 0
A Y
BUF
Y = A
A Y0 0
1 1
A Y
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Chapter 1 <96>
Two-Input Logic Gates
AND
Y = AB
A B Y0 0
0 1
1 0
1 1
AB
Y
OR
Y = A + B
A B Y0 0
0 1
1 0
1 1
AB
Y
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Chapter 1 <97>
Two-Input Logic Gates
AND
Y = AB
A B Y0 0 0
0 1 0
1 0 0
1 1 1
AB
Y
OR
Y = A + B
A B Y0 0 0
0 1 1
1 0 1
1 1 1
AB
Y
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Chapter 1 <98>
More Two-Input Logic Gates
XNOR
Y = A + B
A B Y0 0
0 1
1 0
1 1
AB
Y
XOR NAND NOR
Y = A + B Y = AB Y = A + B
A B Y0 0
0 1
1 0
1 1
A B Y0 0
0 1
1 0
1 1
A B Y0 0
0 1
1 0
1 1
AB
YAB
YAB
Y
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Chapter 1 <99>
More Two-Input Logic Gates
XNOR
Y = A + B
A B Y0 0
0 1
1 0
1 1
AB
Y
XOR NAND NOR
Y = A + B Y = AB Y = A + B
A B Y0 0 0
0 1 1
1 0 1
1 1 0
A B Y0 0 1
0 1 1
1 0 1
1 1 0
A B Y0 0 1
0 1 0
1 0 0
1 1 0
AB
YAB
YAB
Y
1
0
0
1
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Chapter 1 <100>
Multiple-Input Logic Gates
NOR3
Y = A+B+C
B C Y0 0
0 1
1 0
1 1
AB YC
A0
0
0
0
0 0
0 1
1 0
1 1
1
1
1
1
AND3
Y = ABC
AB YC
B C Y0 0
0 1
1 0
1 1
A0
0
0
0
0 0
0 1
1 0
1 1
1
1
1
1
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Chapter 1 <101>
Multiple-Input Logic Gates
• Multi-input XOR = Odd parity (one for odd input=1)
AND3
Y = ABC
AB YC
B C Y0 0
0 1
1 0
1 1
A0
0
0
0
0 0
0 1
1 0
1 1
1
1
1
1
0
0
0
0
0
0
0
1
NOR3
Y = A+B+C
B C Y0 0
0 1
1 0
1 1
AB YC
A0
0
0
0
0 0
0 1
1 0
1 1
1
1
1
1
1
0
0
0
0
0
0
0
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Chapter 1 <102>
Logic Levels
• Discrete voltages represent 1 and 0
• For example:
• 0 = ground (GND) or 0 volts
• 1 = VDD or 5 volts
• What about 4.99 volts? Is that a 0 or a 1?
• What about 3.2 volts?
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Chapter 1 <103>
Logic Levels
• Must have range of voltages for 1 and 0
• Different ranges for inputs and outputs to allow for noise
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Chapter 1 <104>
What is Noise?
• Anything that degrades the signal
• E.g., resistance, power supply noise, coupling to neighboring wires, etc.
• Example: a gate (driver) outputs 5 V but, because of resistance in a long wire, receiver gets 4.5 V
Driver ReceiverNoise
5 V 4.5 V
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Chapter 1 <105>
The Static Discipline
• With logically valid inputs, every circuit element must produce logically valid outputs
• Use limited ranges of voltages to represent discrete values
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Chapter 1 <106>
Real Logic Levels
• Want driver to output “clean” high/low and receiver to handle noisy high/low
Driver Receiver
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Chapter 1 <107>
Real Logic Levels
• Want driver to output “clean” high/low and receiver to handle noisy high/low
Driver Receiver
Forbidden
Zone
NML
NMH
Input CharacteristicsOutput Characteristics
VO H
VDD
VO L
GND
VIH
VIL
Logic High
Input Range
Logic Low
Input Range
Logic High
Output Range
Logic Low
Output Range
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Chapter 1 <108>
Real Logic Levels
Forbidden
Zone
NML
NMH
Input CharacteristicsOutput Characteristics
VO H
VDD
VO L
GND
VIH
VIL
Logic High
Input Range
Logic Low
Input Range
Logic High
Output Range
Logic Low
Output Range
Driver Receiver
NMH = VOH – VIH
NML = VIL – VOL
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Chapter 1 <109>
VDD Scaling
• In 1970’s and 1980’s, VDD = 5 V
• VDD has dropped • 3.3 V, 2.5 V, 1.8 V, 1.5 V, 1.2 V, 1.0 V, …
• Avoid frying tiny transistors
• Save power
• Be careful connecting chips with different supply voltages • Easy to fry if not careful
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Chapter 1 <110>
Logic Family Examples
Logic Family VDD VIL VIH VOL VOH
TTL 5 (4.75 - 5.25) 0.8 2.0 0.4 2.4
CMOS 5 (4.5 - 6) 1.35 3.15 0.33 3.84
LVTTL 3.3 (3 - 3.6) 0.8 2.0 0.4 2.4
LVCMOS 3.3 (3 - 3.6) 0.9 1.8 0.36 2.7
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Chapter 1 <111>
Transistors
• Logic gates built from transistors
• Simple model: 3-ported voltage-controlled switch
• 2 ports connected depending on voltage of 3rd
• d and s are connected (ON) when g is 1
g
s
d
g = 0
s
d
g = 1
s
d
OFF ON
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Chapter 1 <112>
Robert Noyce, 1927-1990
• Nicknamed “Mayor of
Silicon Valley”
• Cofounded Fairchild
Semiconductor in 1957
• Cofounded Intel in
1968
• Co-invented the
integrated circuit
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Chapter 1 <113>
Silicon
• Transistors built from silicon, a semiconductor
• Pure silicon is a poor conductor (no free charges)
• Doped silicon is a good conductor (free charges) • n-type (free negative charges, electrons)
• p-type (free positive charges, holes)
Silicon Lattice
Si SiSi
Si SiSi
Si SiSi
As SiSi
Si SiSi
Si SiSi
B SiSi
Si SiSi
Si SiSi
-
+
+
-
Free electron Free hole
n-Type p-Type
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Chapter 1 <114>
MOS Transistors
• Metal oxide silicon (MOS) transistors:
• Polysilicon (used to be metal) gate
• Oxide (silicon dioxide) insulator
• Doped silicon
n
p
gatesource drain
substrate
SiO2
nMOS
Polysilicon
n
gate
source drain
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Chapter 1 <115>
nMOS Transistors
• Gate = 0
• OFF (no connection between source and drain)
• Gate = 1
• ON (channel between source and drain)
n
p
gate
source drain
substrate
n n
p
gatesource drain
substrate
n
GND
GND
VDD
GND
+++++++
- - - - - - -
channel
Diode connection from p to n doped area current cannot travel from np
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Chapter 1 <116>
pMOS Transistors
• pMOS transistor is opposite of nMOS
• ON when Gate = 0
• OFF when Gate = 1
SiO2
n
gatesource drain
Polysilicon
p p
gate
source drain
substrate
Note bubble on gate to indicate on when low
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Chapter 1 <117>
Transistor Function
• Voltage controlled switch
g
s
d
g = 0
s
d
g = 1
s
d
g
d
s
d
s
d
s
nMOS
pMOS
OFFON
ONOFF
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Chapter 1 <118>
Transistor Composition
• nMOS: pass good 0’s
• Connect source to GND
• “Pull down” transistor
• pMOS: pass good 1’s
• Connect source to VDD
• “Pull up” transistor
• Build logic gates from composition
• CMOS = complementary MOS
pMOS
pull-up
network
output
inputs
nMOS
pull-down
network
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Chapter 1 <119>
CMOS Gate Structure
• Pull-up pMOS network connects to 𝑉𝐷𝐷
• Pull-down nMOS network connects to 𝐺𝑁𝐷
• Use series and parallel connections to implement gate logic
pMOS
pull-up
network
output
inputs
nMOS
pull-down
network
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Chapter 1 <120>
CMOS Gates: NOT Gate
V
DD
A Y
GND
N1
P1
NOT
Y = A
A Y0 1
1 0
A Y
A P1 N1 Y
0
1
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Chapter 1 <121>
CMOS Gates: NOT Gate
V
DD
A Y
GND
N1
P1
NOT
Y = A
A Y0 1
1 0
A Y
A P1 N1 Y
0 ON OFF 1
1 OFF ON 0
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Chapter 1 <122>
CMOS Gates: NAND Gate
A
B
Y
N2
N1
P2 P1
NAND
Y = AB
A B Y0 0 1
0 1 1
1 0 1
1 1 0
AB
Y
A B P1 P2 N1 N2 Y
0 0
0 1
1 0
1 1
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Chapter 1 <123>
CMOS Gates: NAND Gate
A
B
Y
N2
N1
P2 P1
NAND
Y = AB
A B Y0 0 1
0 1 1
1 0 1
1 1 0
AB
Y
A B P1 P2 N1 N2 Y
0 0 ON ON OFF OFF 1
0 1 ON OFF OFF ON 1
1 0 OFF ON ON OFF 1
1 1 OFF OFF ON ON 0
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Chapter 1 <124>
CMOS Gates: NOR Gate
• How can you build three input 𝐴, 𝐵, 𝐶 NOR gate?
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Chapter 1 <125>
CMOS Gates: NOR Gate
• How can you build three input 𝐴, 𝐵, 𝐶 NOR gate?
B
CY
A Only high output when all three pMOS in series are “on” and create a path from output to 𝑉𝐷𝐷
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Chapter 1 <126>
CMOS Gates: AND Gate
• How can you build 2 input AND gate?
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Chapter 1 <127>
CMOS Gates: AND Gate
• How can you build 2 input AND gate?
AB
Y
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Chapter 1 <128>
CMOS Gates: AND Gate
• How can you build 2 input AND gate?
AB
Y
A
B
Y
N2
N1
P2 P1
VDD
A Y
GND
N1
P1
Note: AND requires 2 more gates than NAND. Inverted logic is more efficient implementation.
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Chapter 1 <129>
Transmission Gates
• nMOS pass 1’s poorly, pMOS pass 0’s poorly
• Transmission gate is for passing signal
• Pass both 0 and 1 well
• When EN = 1, the switch is ON:
• 𝐸𝑁 = 0 and A is connected to B
• When EN = 0, the switch is OFF:
• A is not connected to B
A B
EN
EN
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Chapter 1 <130>
Psuedo-nMOS
• Replace pull-up network with weak pMOS transistor that is always on • pMOS gate tied to ground
• pMOS transistor: pulls output HIGH only when nMOS network not pulling it LOW
Y
inputsnMOS
pull-down
network
weak
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Chapter 1 <131>
Psuedo-nMOS Example: NOR4
• How many transistors needed?
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Chapter 1 <132>
Psuedo-nMOS Example: NOR4
• How many transistors needed?
• Only 5 since a single pMOS is used
A B
Y
weak
C D
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Chapter 1 <133>
Gordon Moore, 1929-
• Cofounded Intel in 1968 with Robert Noyce.
• Moore’s Law: number of transistors on a computer chip doubles every year (observed in 1965)
• Since 1975, transistor counts have doubled every two years.
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Chapter 1 <134>
Moore’s Law
• Transistor count doubles every 2 years
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Chapter 1 <135>
Moore’s Law Trends
GPUs
• “If the automobile had followed the same development cycle as the computer, a Rolls-Royce would today cost $100, get one million miles to the gallon, and explode once a year . . .”
– Robert Cringley
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Chapter 1 <136>
Power Consumption
• Power = Energy consumed per unit time
• Two types of power
• Dynamic power consumption
• Static power consumption
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Chapter 1 <137>
Dynamic Power Consumption
• Power to charge transistor gate capacitances
• Energy required to charge a capacitance, 𝐶, to 𝑉𝐷𝐷 is 𝐶𝑉𝐷𝐷
2
• Circuit running at frequency 𝑓: transistors switch (from 1 to 0 or vice versa) at that frequency
• Capacitor is charged 𝑓/2 times per second (discharging from 1 to 0 is free)
• Dynamic power consumption
𝑃𝑑𝑦𝑛𝑎𝑚𝑖𝑐 =
1
2𝐶𝑉𝐷𝐷
2 𝑓
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Chapter 1 <138>
Static Power Consumption
• Power consumed when no gates are switching
• Caused by the quiescent supply current, 𝐼𝐷𝐷 (also called the leakage current)
• Static power consumption
𝑃𝑠𝑡𝑎𝑡𝑖𝑐 = 𝐼𝐷𝐷𝑉𝐷𝐷
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Chapter 1 <139>
Power Consumption Example
• Estimate the power consumption of a wireless handheld computer
• 𝑉_𝐷𝐷 = 1.2 V
• 𝐶 = 20 nF
• 𝑓 = 1 GHz
• 𝐼𝐷𝐷 = 20 mA
• Total power is sum of dynamic and static
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Chapter 1 <140>
Power Consumption Example
• Estimate the power consumption of a wireless handheld computer
• 𝑉_𝐷𝐷 = 1.2 V
• 𝐶 = 20 nF
• 𝑓 = 1 GHz
• 𝐼𝐷𝐷 = 20 mA
• Total power is sum of dynamic and static
𝑃 =1
2𝐶𝑉𝐷𝐷
2 𝑓 + 𝐼𝐷𝐷𝑉𝐷𝐷
=1
220 n 1.2 2 1 G
+ 20 m 1.2 = 14.4 + 0.024 W = 14.4 W