Penn ESE370 Fall DeHon 1 ESE370: Circuit-Level Modeling, Design, and Optimization for Digital Systems Day 1: September 5, 2012 Introduction and Overview

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? Penn ESE370 Fall DeHon 2

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? Penn ESE370 Fall DeHon 3

Sample Problems Penn ESE370 Fall DeHon 4

What does this circuit do? How fast does it operate? Penn ESE370 Fall DeHon 5

What’s wrong here? How fix? Penn ESE370 Fall DeHon 6

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? Penn ESE370 Fall DeHon 7

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? Penn ESE370 Fall DeHon 8

Outline Motivating Questions What this course is about Objectives What you need to know Structure Policies Content Penn ESE370 Fall DeHon 9

Deconstruction Circuit-Level Modeling, Design, and Optimization for Digital Systems Penn ESE370 Fall DeHon 10 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)

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 Fall 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? Penn ESE370 Fall DeHon 12

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 Penn ESE370 Fall DeHon 13

Penn ESE370 Fall DeHon 14 You are here. ESE205/215, ESE319 ESE218 Phys151 ESE170 (ESE200) CIS240 CIS371, ESE534 CIS380 CIS120

Objectives Penn ESE370 Fall DeHon 15

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) Penn ESE370 Fall DeHon 16

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 Penn ESE370 Fall DeHon 17

What you Need to Know coming in to this course Penn ESE370 Fall DeHon 18

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 Penn ESE370 Fall DeHon 19

Review Session Poll Tonight in Ketterer Will work? 5pm 6pm 7pm 8pm Also poll TA hour M & W during rest of term. Penn ESE370 Fall DeHon 20

Structure Penn ESE370 Fall DeHon 21

Structure MWF Lecture Reading from text 4 lecture periods  Lab –3 Detkin See phenomena first hand before simulate –1 Ketterer  SPICE Intro Penn ESE370 Fall DeHon 22

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 Penn ESE370 Fall DeHon 23

Structures Homeworks – week long (7 total) Projects – two weeks long (2 total) –Design oriented –On two main topics Computation Storage Two midterms Final Penn ESE370 Fall DeHon 24

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 Penn ESE370 Fall DeHon 25

Policies Penn ESE370 Fall DeHon 26

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 Penn ESE370 Fall DeHon 27

Content Penn ESE370 Fall DeHon 28

Content Logic (Computation) [7 weeks] –Combinational –Sequential Storage [2 weeks] Communication [3 weeks] Penn ESE370 Fall DeHon 29

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 Penn ESE370 Fall DeHon 30

Content Memory –No Lab component –RAM Organization –Driving Large Capacitances –Signal amplification/restoration –Project: design a SRAM Register File Penn ESE370 Fall DeHon 31

Content Communication –In Lab Measure inductive ground bounce, crosstalk Experiment with transmissions lines, termination –Noise Crosstalk Inductive Ionizing particles, shot –Transmission Lines Penn ESE370 Fall DeHon 32

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) Penn ESE370 Fall DeHon 33

Wrapup Admin –Find web, get text, assigned reading… – –Piazza home Big Ideas / takeaway –Model to enable design Diagnostic Quiz next time –Review as needed Remaining Questions? Penn ESE370 Fall DeHon 34