Implementing Logic Gates and Circuits

Discussion D5.3

Section 11-2

Implementing Logic Gates and Circuits

• Logic With Relays

• Integrated Circuit Implementation of Gates

• Transistor-Transistor Logic (TTL)

• Programmable Logic Devices (PLDs)

• Complex Programmable Logic Devices (CPLDs)

• Field Programmable Gate Arrays (FPGAs)

Relays

Normally Open Relay

A

B

CA

B

C

Normally Closed Relay

A-B closed when C = 1(current through coil)

A-B open when C = 1(current through coil)

NOT Gate5V

XY

0 1

closed

openX Y

01

10

X Y

Y

NOTX Y

Y = ~X

NOT

NOT Gate5V

X Y01

closed

open

X Y

01

10

X Y

Y

NOTX Y

Y = ~X

NOT

AND Gate

X Y Z0 0 00 1 01 0 01 1 1

X

Y

Z

5V

X

Y

Z

AND Gate

X Y Z0 0 00 1 01 0 01 1 1

X

Y

Z

5V

X

Y

Z

0

0

AND Gate

X Y Z0 0 00 1 01 0 01 1 1

X

Y

Z

0

1

X

Y

Z

5VX

Y

Z

5V

X

Y

Z

5VX

Y

Z

5V

AND Gate

X Y Z0 0 00 1 01 0 01 1 1

X

Y

Z

1

0

AND Gate

X Y Z0 0 00 1 01 0 01 1 1

X

Y

Z

1

1

X

Y

Z

5VX

Y

Z

5V

OR Gate

X Y Z0 0 00 1 11 0 11 1 1

5V

X

Y

Z

X

YZ

OR Gate

X Y Z0 0 00 1 11 0 11 1 1

5V

X

Y

Z

X

YZ

0

0

OR Gate

X Y Z0 0 00 1 11 0 11 1 1

X

YZ

0

1

5V

X

Y

Z

5V

X

Y

Z

X

Y

Z

OR Gate

X Y Z0 0 00 1 11 0 11 1 1

X

YZ

1

0

5V

X

Y

Z

5V

X

Y

Z

X

Y

Z

OR Gate

X Y Z0 0 00 1 11 0 11 1 1

X

YZ

1

1

5V

X

Y

Z

5V

X

Y

Z

X

Y

Z

Implementing Gates Using MOSFET Integrated Circuits

Relays

Normally openNormally closed

A

B

C

A

B

C

A

B

C

nMOS transistorA-B closed whenC = 1(normally open)

pMOS transistorA-B closed whenC = 0(normally closed)

NOT Gate5V

X YY = ~X

X Y

X Y

01

10

NOT Gate5V

X YY = ~X

X Y

0 1

X Y

01

10

NOT Gate5V

X YY = ~X

X Y

1 0

X Y

01

10

NAND Gate

X

Y

Z

5V

X

YZ

X Y Z0 0 10 1 11 0 11 1 0

NAND Gate

X

Y

Z

5V

X

YZ

X Y Z0 0 10 1 11 0 11 1 0

0

0

NAND Gate

X

Y

Z

5V

X

YZ

X Y Z0 0 10 1 11 0 11 1 0

0

1

NAND Gate

X

Y

Z

5V

X

YZ

X Y Z0 0 10 1 11 0 11 1 0

1

0

NAND Gate

X

Y

Z

5V

X

YZ

X Y Z0 0 10 1 11 0 11 1 0

1

1

NOR Gate

X

Y

Z

5V

XY

Z

X Y Z0 0 10 1 01 0 01 1 0

NOR Gate

X

Y

Z

5V

XY

Z

X Y Z0 0 10 1 01 0 01 1 0

0

0

NOR Gate

X

Y

Z

5V

XY

Z

X Y Z0 0 10 1 01 0 01 1 0

0

1

NOR Gate

X

Y

Z

5V

XY

Z

X Y Z0 0 10 1 01 0 01 1 0

1

0

NOR Gate

X

Y

Z

5V

XY

Z

X Y Z0 0 10 1 01 0 01 1 0

1

1

AND Gate

X

Y

5V

Z

5V

NAND-NOT

OR Gate

X

Y

5V

Z

5V

NOR-NOT

Transistor-Transistor Logic(TTL)

• Developed in mid-1960s

• Large family (74xx) of chips from basic gates to arithmetic logic units

• Becoming obsolete with the development of programmable logic devices (PLDs)

TTL Chips

1 2 3 4 5 6 7

8 9 1011121314

1 2 3 4 5 6 7

8 9 1011121314

1 2 3 4 5 6 7

8 9 1011121314

7404 Hex Inverters

7408 Quad 2-Input AND Gates

7432 Quad 2-Input OR Gates

TTL NAND, NOR, XOR

1 2 3 4 5 6 7

8 9 1011121314

1 2 3 4 5 6 7

8 9 1011121314

1 2 3 4 5 6 7

8 9 1011121314

7400 Quad 2-Input NAND Gates

7402 Quad 2-Input NOR Gates

7486 Quad 2-Input EXCLUSIVE-OR Gates

TTL Multiple-input Gates

1 2 3 4 5 6 7

8 9 1011121314

1 2 3 4 5 6 7

8 9 1011121314

7421 Dual 4-Input AND Gates

7430 8-Input NAND Gate

Small-Scale Integrated (SSI) Circuits

• 1 to 10 gates

• NAND gate has 4 transistors

Medium-Scale Integrated (MSI) Circuits

• 10-100 gates

• Adders

• Comparators

• Multiplexers

• Decoders

Large-Scale Integrated (LSI) Circuits

• 100-1000 gates

• Arithmetic Logic Units

Very-Large-Scale Integrated (VLSI) Circuits

• >1000 gates

• Microprocessors

• Programmable Logic Devices (PLDs)

• Complex Programmable Logic Devices (CPLDs)

• Field Programmable Gate Arrays (FPGAs)

Basic PLD StructureX Y

X ~X Y ~Y

A

B

1

2

Z

removablejumpers

Alternate PLD RepresentationX Y

X ~X Y ~Y

A

B

ZX X X X

X X X X

1

2

PLD Connections for XORX Y

X ~X Y ~Y

A

B

Z = X & ~Y | ~X & Y

X X

X X

1

2

1975 – Signetics invents the FPLA

1978 – MMI introduces the PAL

1983 – AMD introduces the 22V10

1984 – Lattice introduces the GAL – an electrically erasable PAL

The GAL 16V8

1

2

3

4

5

6

7

9

10 11

12

8

19

20

17

18

15

16

13

14

GND

Vcc I/CLK I I/O

I I

I

I

I

I

I

I/OE

I/O

I/O

I/O

I/O

I/O

I/O

I/O

GAL 16V8

Structure of the GAL 16V8 PLDX X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

Pin 2

Pin 3

Pin 19

X

Y

Z

GAL 16V8 Input Buffer

XX

~X

Structure of the GAL 16V8 PLDX X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

Pin 2

Pin 3

Pin 19

X

Y

Z

GAL 16V8 Polarity Control

OE

X

A

B

C

X closed B = 0 C = A open B = 1 C = ~A

Polarity

Pin

Structure of the GAL 16V8 PLDX X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

X X X X X X X X

Pin 2

Pin 3

Pin 19

X

Y

Z

XC9500 CPLDs

• 5 volt in-system programmable (ISP) CPLDs

• 5 ns pin-to-pin• 36 to 288

macrocells (6400 gates)

• Industry’s best pin-locking architecture

• 10,000 program/erase cycles

• Complete IEEE 1149.1 JTAG capability

FunctionBlock 1

JTAGController

FunctionBlock 2

I/O

FunctionBlock 4

3

Global Tri-

States 2 or 4

FunctionBlock 3

I/O

In-SystemProgramming Controller

FastCONNECTSwitch Matrix

JTAG Port

3

I/O

I/O

Global Set/Reset

Global Clocks

I/OBlocks

1

XC9500 Function Block

ToFastCONNECT

FromFastCONNECT

2 or 43 GlobalTri-State

GlobalClocks

I/O

I/O

36

Product-Term

Allocator

Macrocell 1

ANDArray

Macrocell 18

Each function block is like a 36V18 !

XC9500 Product Family

9536

Macrocells

Usable Gates

tPD (ns)

Registers

Max I/O

36 72 108 144 216

800 1600 2400 3200 4800

5 7.5 7.5 7.5 10

36 72 108 144 216

34 72 108 133 166

Packages VQ44PC44 PC44

PC84TQ100PQ100

PC84TQ100PQ100PQ160

PQ100PQ160

288

6400

10

288

192

HQ208BG352

PQ160HQ208BG352

9572 95108 95144 95216 95288

Xilinx 95108

• 6 function blocks– Each contains 18 macro cells– Each macro cell behaves like a GAL32V18

• AND-OR array for sum-of-products

• 32 inputs and 18 outputs

Architecture of the Xilinx XC95108 CPLD

PLDT-3

XilinxXC95108 CPLD

7 segment display

Switches

LEDs

Buttons

PLDT-3

• 12 macro cells connected to I/O pins

• 4 pushbuttons

• 8 toggle switches

• 8 dip switches

• 16 LEDs

• 2 7-segment displays

• On-board clock signals (4 MHz and 1 Hz)

FPGAs

Field Programmable Gate Arrays

1985 – Xilinx introduces the LCA (Logic Cell Array)

The Xilinx XC3000 CLB (configurable logic block).

CLB

CLB

CLB

CLB

SwitchMatrix

ProgrammableInterconnect I/O Blocks (IOBs)

ConfigurableLogic Blocks (CLBs)

D Q

SlewRate

Control

PassivePull-Up,

Pull-Down

Delay

Vcc

OutputBuffer

InputBuffer

Q D

Pad

D QSD

RDEC

S/RControl

D QSD

RDEC

S/RControl

1

1

F'

G'

H'

DIN

F'

G'

H'

DIN

F'

G'

H'

H'

HFunc.Gen.

GFunc.Gen.

FFunc.Gen.

G4G3G2G1

F4F3F2F1

C4C1 C2 C3

K

Y

X

H1 DIN S/R EC

1991 – Xilinx introduces the XC4000 Architecture

XC4003 contained 440,000 transistors0.7-micron process

XC4000E/X Configurable Logic Blocks

D QSD

RDEC

S/RControl

D QSD

RDEC

S/RControl

1

1

F'

G'

H'

DIN

F'

G'

H'

DIN

F'

G'

H'

H'

HFunc.Gen.

GFunc.Gen.

FFunc.Gen.

G4G3G2G1

F4F3F2F1

C4C1 C2 C3

K

YQ

Y

XQ

X

H1 DIN S/R EC

• 2 Four-input function generators (Look Up Tables)- 16x1 RAM or Logic function

• 2 Registers- Each can be configured as Flip Flop or Latch- Independent clock polarity- Synchronous and asynchronous Set/Reset

Look Up Tables

Capacity is limited by number of inputs, not complexity

Choose to use each function generator as 4 input logic (LUT) or as high speed sync.dual port RAM

• Combinatorial Logic is stored in 16x1 SRAM Look Up Tables (LUTs) in a CLB

• Example:

A B C D Z

0 0 0 0 00 0 0 1 00 0 1 0 00 0 1 1 10 1 0 0 10 1 0 1 1 . . .1 1 0 0 01 1 0 1 01 1 1 0 01 1 1 1 1

Look Up Table

Combinatorial Logic

AB

CD

Z

4-bit address

GFunc.Gen.

G4G3G2G1

WE

2(2 )4

= 64K !

What’s Really In that Chip?

CLB(Red)

Switch Matrix

Long Lines(Purple)

Direct Interconnect (Green)

Routed Wires (Blue)

Programmable Interconnect Points, PIPs (White)

1998 – Xilinx introduces the Virtex®™ FPGA family

0.25-micron process

2003 – Xilinx introduces the Spartan®™-3 family of products

Very low cost

World’s first90 nm FPGA

Block diagram of Xilinx Spartan IIE FPGA

Each Spartan IIE CLB contains two of these CLB slices

Block diagram of Xilinx Spartan-3 FPGA

Each Spartan-3 CLB contains four CLB slices

CPLDs vs. FPGAs

Moore's Law(Doubling every 2 years)

0.001

0.01

0.1

1

10

100

1000

10000

1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010

Year

Tra

nsi

sto

rs (

in m

illio

ns

)

8080

286

486 Pentium

Pentium II

Pentium 4

64K

1M

4M

16M

Memory

Microprocessor

x

Xilinx will release the world’s first one-billion transistor device this year