ESE370:
Circuit-Level
Modeling, Design, and Optimization
for Digital Systems
Day 1: September 5, 2012
Introduction and Overview
1
Penn ESE370 Fall2012 -- DeHon
Questions
• How fast can my computer run?
– What limits this speed?
– What can I do to make it run faster?
• How can I extend the battery life on my
gadget?
– How much energy must my computation take?
• How small can I make a memory?
– Why does DRAM need to be refreshed?
2
Penn ESE370 Fall2012 -- DeHon
Questions
• How many bits/second can I send over
a link?
– What limits this?
– How do I maximize?
• How does technology scaling change
these answers?
• What can I rely on technology to deliver?
3
Penn ESE370 Fall2012 -- DeHon
Sample Problems
4
Penn ESE370 Fall2012 -- DeHon
What does this circuit do?
How fast does it operate?
5
Penn ESE370 Fall2012 -- DeHon
What’s wrong here?
How fix?
6
Penn ESE370 Fall2012 -- DeHon
Limits?
•
•
•
•
Consider a 45nm technology
Typical gate with W=3, 2-input NOR
Use chip in cell phone
What prevents us from running 1 billion
transistor chip at 10GHz?
7
Penn ESE370 Fall2012 -- DeHon
Impact of Voltage?
• If have a chip running at 1GHz with a
1V power supply dissipating 1W.
• What happens if we cut the power
supply to 500mV?
– Speed?
– Power?
8
Penn ESE370 Fall2012 -- DeHon
Outline
•
•
•
•
•
•
•
Motivating Questions
What this course is about
Objectives
What you need to know
Structure
Policies
Content
9
Penn ESE370 Fall2012 -- DeHon
Deconstruction
• Circuit-Level
Modeling,
Design, and
Optimization
for Digital Systems
Look below the gates
…transistors, resistance,
capacitance, inductance…
Abstract and predict
Create
Make efficient
(fast,low energy,small)
Compute, store, transmit
binary values (0s, 1s)
10
Penn ESE370 Fall2012 -- DeHon
What course about
• What Computer Engineers need to
know about the physical properties in
order to design efficient digital circuits
• Physical Properties
– Delay, Energy (Power), Area, Reliability
• Efficient
– Fast, Low Energy, Small, Won’t Fail (very often)
• Digital Circuits
– Computation, Storage, Communication
Penn ESE370 Fall2012 -- DeHon
11
What course is about
• Modeling and abstraction
– Predict circuit behavior
– Well enough to know our design will work
– …with specific properties
• Speed, energy, ….
– Well enough to reason about design and
optimization
• What knob can I turn to make faster?
• How much faster can I expect to make it?
12
Penn ESE370 Fall2012 -- DeHon
What course is about
• Modeling and abstraction
– Back-of-the-envelope
• Simple enough to reason about
– …without a calculator…
– Sensitive to phenomenology
• Able to think through the details
– With computer assistance
• …understanding even that is a simplified
approximation
13
Penn ESE370 Fall2012 -- DeHon
CIS120
CIS380
CIS240
CIS371,
ESE534
ESE170 (ESE200)
You are here.
ESE205/215, ESE319
ESE218
Penn ESE370 Fall2012 -- DeHon
Phys151
14
Objectives
15
Penn ESE370 Fall2012 -- DeHon
You will learn
• disciplines for robust digital logic and
signaling
– (e.g., restoration, clocking)
• where delay, energy, area, and noise arises
in gates, memory, and interconnect
• how to model these physical effects
– back-of-the-envelope design
• (e.g. RC and Elmore delay)
– detailed simulation (e.g. SPICE)
16
Penn ESE370 Fall2012 -- DeHon
You will learn
• the nature of tradeoffs in optimization
– Among delay, energy, area, noise
• how to design and optimize
– logic, memory, and interconnect structures
– at the gate, transistor, and wire level
• how technology scales
– and its impact on digital circuits and
computer systems
17
Penn ESE370 Fall2012 -- DeHon
What you Need to Know
coming in to this course
18
Penn ESE370 Fall2012 -- DeHon
What you need to know
• See pages linked from course page
• CIS170
– Gates, Boolean logic, DeMorgan’s,
optimization
• CIS215
– RLC circuit analysis
– Diagnostic Quiz next time – end of class
19
Penn ESE370 Fall2012 -- DeHon
Review Session Poll
Tonight in Ketterer
Will work?
• 5pm
• 6pm
• 7pm
• 8pm
Also poll TA hour M & W during rest of term.
20
Penn ESE370 Fall2012 -- DeHon
Structure
21
Penn ESE370 Fall2012 -- DeHon
Structure
• MWF Lecture
• Reading from text
• 4 lecture periods  Lab
– 3 Detkin
• See phenomena first hand before simulate
– 1 Ketterer  SPICE Intro
22
Penn ESE370 Fall2012 -- DeHon
SPICE
• Simulation Program with Integrated
Circuit Emphasis
– Industry standard analog circuit simulator
– Non-linear, differential equation solver
specialized for circuits
• Integrated circuits – simply impractical
to build to debug
– Must simulate to optimize/validate design
23
Penn ESE370 Fall2012 -- DeHon
Structures
• Homeworks – week long (7 total)
• Projects – two weeks long (2 total)
– Design oriented
– On two main topics
• Computation
• Storage
• Two midterms
• Final
24
Penn ESE370 Fall2012 -- DeHon
Admin
• Won’t bring printouts to class
• Use course calendar
– Lectures online before class
• (most of the time)
– Homeworks linked
• Homework 1 out now (tied to first lab visit)
– Reading specified
25
Penn ESE370 Fall2012 -- DeHon
Policies
26
Penn ESE370 Fall2012 -- DeHon
Policies
See web page for details
• Turnin homework on blackboard
– No handwritten homework
– Use CAD Tools for circuit drawings
• Late homework penalty
• Individual work (HW & Project)
– CAD drawings, simulations, analysis, writeups
– May discuss strategies, but must acknowledge
27
Penn ESE370 Fall2012 -- DeHon
Content
28
Penn ESE370 Fall2012 -- DeHon
Content
• Logic (Computation)
[7 weeks]
– Combinational
– Sequential
• Storage
• Communication
[2 weeks]
[3 weeks]
29
Penn ESE370 Fall2012 -- DeHon
Content
• Logic
– Transistors  Gates
– In Lab: build gate, measure delay, restore
– Restoration
– Delay
– Area (no layout  ESE570)
– Energy
– Synchronous (flip-flops, clocking, dynamic)
– Project: fast ripple-carry adder
30
Penn ESE370 Fall2012 -- DeHon
Content
• Memory
– No Lab component
– RAM Organization
– Driving Large Capacitances
– Signal amplification/restoration
– Project: design a SRAM Register File
31
Penn ESE370 Fall2012 -- DeHon
Content
• Communication
– In Lab
• Measure inductive ground bounce, crosstalk
• Experiment with transmissions lines, termination
– Noise
• Crosstalk
• Inductive
• Ionizing particles, shot
– Transmission Lines
32
Penn ESE370 Fall2012 -- DeHon
Advice
• Course is hard (but valuable)
• Must read text
• Learning is spread over all components
– Lecture, reading, homeworks, projects,
exams
• Must be able to get quantitative
answers to get an A (maybe even for B)
33
Penn ESE370 Fall2012 -- DeHon
Wrapup
• Admin
– Find web, get text, assigned reading…
– http://www.seas.upenn.edu/~ese370
– Piazza
https://piazza.com/upenn/fall2012/ese370/
home
• Big Ideas / takeaway
– Model to enable design
• Diagnostic Quiz next time
– Review as needed
• Remaining Questions?
Penn ESE370 Fall2012 -- DeHon
34