Engr354 Chapter 1 1

Engr354: Digital Logic Circuits

Chapter 1: Design Concepts

Curtis Nelson

Design Concepts

• Digital hardware systems;• Digital hardware implementation methods;

– Standard chips;– Programmable logic devices (PLA’s);– Application Specific Integrated Circuits (ASIC’s);– Fully custom IC’s;– VHDL.

• Design process.

Engr354 Chapter 1 2

A Digital Hardware System

Printed Circuit Boards

Engr354 Chapter 1 3

A Digital Hardware System

AMD’s Barcelona Multicore Chip

http://www.techwarelabs.com/reviews/processors/barcelona/

Core 1 Core 2

Core 3 Core 4

Northbridge

512K

B L

2

512K

B L

2 51

2KB

L2

512K

B L

2

2MB

shar

ed L

3 C

ache

q Four out-of-order cores on one chip

q 1.9 GHz clock rate

q 65nm technology

q Three levels of caches (L1, L2, L3) on chip

q Integrated Northbridge

Engr354 Chapter 1 4

VLSI Design 7

Birth of Modern Electronics -- 1947AT&T Bell Laboratories -- Invention of Point Contact Transistor

William Shockley, Walter Brittain, and John BardeenWinners of the 1956 Nobel Prize in Physics

Vacuum tubes ruled in first half of 20th century Large, expensive, power-hungry, unreliable

Read Crystal Fire

by Riordan, Hoddeson

VLSI Design 8

Microelectronic Revolution -- 1958The First Integrated Circuit – Jack Kilby, Texas Instruments

1 Transistor and 4 Other Devices on 1 ChipWinner of the 2000 Nobel Prize

Engr354 Chapter 1 5

VLSI Design 9

8080

• 16-bit address bus (1974)– Used in Altair computer

• (early hobbyist PC)

• Characteristics– 6 µm process– 4500 transistors– 2 MHz– 8-bit word size– 40-pin DIP package

VLSI Design 10

First 65,536 Bit Dynamic Memory Chip --1977

IBM Corporation

Engr354 Chapter 1 6

VLSI Design 11

Pentium

• Superscalar (1993)– 2 instructions per cycle– Separate 8KB I$ & D$

• Characteristics– 0.8-0.35 µm process– 3.2M transistors– 60-300 MHz– 32-bit word size– 296-pin PGA

• Caches, datapath,FPU, control

VLSI Design 12

Pentium 4

• Deep pipeline (2001)– Very fast clock– 256-1024 KB L2$

• Characteristics– 180-90 nm process– 42-125M transistors– 1.4-3.4 GHz– 32-bit word size– 478-pin PGA

• Units start to becomeinvisible on this scale

Engr354 Chapter 1 7

VLSI Design 13

Gate Array, Semi-Custom, and Full-Custom ICs

VLSI Technology

Gate Array

Standard Cell

Full Custom

Chip Area Ratios:3:2:1

A Silicon Wafer

Engr354 Chapter 1 8

ITRS Roadmap

Standard Chips

• Realize common logic functions;• Usually less than 100 transistors;• Common ones will be found in your lab kits;• You will use them in some homework assignments;• Not used much today as they occupy too much space on

printed circuit boards (PCB’s).

Engr354 Chapter 1 9

Standard Chips

Standard Chips

Engr354 Chapter 1 10

Programmable Logic Devices (PLD’s)

• Realize much more complicated logic circuits than a standard chip;

• Often reprogrammable;• Field-programmable gate arrays (FPGA) will soon use

more than 100 million transistors;• Widely used today;• You will use one on your logic board.

Memory blockGroup of 8 logic cells

Interconnectionwires

Field Programmable Gate Array (FPGA)

Engr354 Chapter 1 11

Custom Designed Chips

• PLD’s are not very efficient so they may not meet performance or cost objectives;

• May need to design a custom or semi-custom chip (ASIC);• Advantage: optimized for a given task;• Disadvantage: more complex design and manufacturing

process, more design time;• Custom ASIC design taught in Engr434, VLSI Design.

Custom Designed Chips

Engr354 Chapter 1 12

VHDL – A Structured Programming Language

Design concept

Successful design

Initial design

Simulation

Design correct?

Redesign

No

Yes

Basic Digital Design Loop

Engr354 Chapter 1 13

Summary

• Digital hardware systems;• Digital hardware implementation methods;

– Standard chips;– Programmable logic devices (PLA’s);– Application Specific Integrated Circuits (ASIC’s);– Fully custom IC’s;– VHDL.

• Design Process.