Abstraction & Digital Logic: From Transistors to Gates
Problem Transformation – levels of abstraction
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The desired behavior: the application
Natural Language Algorithm Program Machine Architecture Micro-architecture Logic Circuits Devices
The building blocks: electronic devices
The Program Level
Most computers run a management program called the operating system (OS).
Application programs interface to the machine architecture via the OS.
This lecture Data An example:
Program (Software)
Application Program
Operating System
Application Program Operating System
PowerPoint
Windows 10
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Course Outline – What is Next?
The building blocks of computers: logic gates How to represent information
The basic algorithm: the von Neumann model MIPS structure
Programming the machine: assembly language
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How do computers communicate?
All creatures communicate in a particular language.
A sentence in a language may be a specific arrangement of symbols
“chirp squak”
“ooh ooh aah aah”
A digital computer, at its most basic level, speaks the binary language
The binary language has only 2 symbols: 1 (ON), 0 (OFF)
A certain string of 1s and 0s can be used to convey information in the binary language!
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The Transistor: building block of computers
Microprocessors contain many transistors
15-Core Xeon Ivy Bridge-EX (2014): 4310 million 10-Core Xeon Westmere-EX (2011): 2600 million Six-Core Core i7(2010): 1170 million
AMD 6-core Opteron (2009): 904 million
Intel Core i7 Quad (2008): 731 million
Intel Core 2 Duo (2006): 291 million
IBM/Apple PowerPC G5 (2003): 58 million
Intel Pentium 4 (2000): 42 million
IBM PowerPC 750FX (2002): 38 million
Intel 4004 (1971): 2300
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What Is a Transistor?
A switch, which can close between the source and the drain
Changing the voltage of the gate lets you change the current flow between the source and drain (closing or opening the switch)
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What is a transistor?
Logically, each transistor is used as a switch Combined to implement logic functions
AND, OR, NOT
Combined to build higher-level structures
Adder, multiplexer, decoder, register, … Combined to build a processor
ARM, Core 2 Duo, i7 9700k, etc
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Simple switch circuit
ECE 101
Switch open:
No current through
circuit Light is off Vout is +2.9V
Switch closed: Short circuit across
switch Current flows Light is on Vout is 0V
Switch-based circuits can
easily represent two states: on/off, open/closed, voltage/no voltage.
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1. CMOS Logic Operation
At its heart, a digital computer can understand only 1s (ON) and 0s (OFF). The computer is made up of CMOS switches which convey this information from one module to another
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Tas
k – Problem Statement
Algorithm
NMOS
PMOS
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Pro
Inst
Log
gram
ruction Set Architecture
Microarchitecture
ic Gates
Devices
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NMOS
PMOS
Logic 1/0
Logic 1/0
Out
GND
Out
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1
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0
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Out= Vdd
Complementary MOS (CMOS)
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NOT gate (Inverter )
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Vdd V (Logic 1) 0 V (Logic 0)
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