Lecture A: Logic Design and Gates - 1680x1050.com · Lecture A: Logic Design and Gates ... Lab...

50
Lecture A: Logic Design and Gates Syllabus My office hours 9.15-10.35am T,Th or [email protected] 333G WERC Text: Brown and Vranesic “Fundamentals of Digital Logic,” » Buy it.. Or borrow it » Other book: Katz – I have one copy Grading » Three Hour exams: H1-20%, H2-20%, H3-25% » Lab 20%, Homework 10%, Pop quizzes 5% No Cheating » Cheaters will not be tolerated Class STARTS AT 8am I will NOT repeat lectures or material covered during lecture Help Desk Hours/Sessions will be announced Reading Announcements Get hold of the Reading List Stay ahead Pull together some questions Review what you’ve read after the lecture Lab Starts NEXT WEEK

Transcript of Lecture A: Logic Design and Gates - 1680x1050.com · Lecture A: Logic Design and Gates ... Lab...

Lectu

re A

: L

og

ic D

esig

n a

nd

Gate

s

•S

yll

ab

us

–M

y o

ffic

e h

ou

rs 9

.15-1

0.3

5am

T,T

ho

r g

ch

oi@

ece.t

am

u.e

du

333G

WE

RC

–T

ext:

Bro

wn

an

d V

ran

esic

“F

un

dam

en

tals

of

Dig

ital L

og

ic,”

»B

uy i

t.. O

r b

orr

ow

it

»O

ther

bo

ok:

Katz

–I h

ave o

ne c

op

y–

Gra

din

Th

ree H

ou

r exam

s:

H1-2

0%

, H

2-2

0%

, H

3-2

5%

»L

ab

20

%,

Ho

mew

ork

10

%,

Po

p q

uiz

zes 5

%–

No

Ch

eati

ng

»C

heate

rs w

ill n

ot

be t

ole

rate

d

•C

lass S

TA

RT

S A

T 8

am

–I w

ill N

OT

rep

eat

lectu

res o

r m

ate

rial co

vere

d d

uri

ng

lectu

re

•H

elp

Desk H

ou

rs/S

essio

ns w

ill b

e a

nn

ou

nced

Read

ing

An

no

un

cem

en

ts–

Get

ho

ld o

f th

e R

ead

ing

Lis

t–

Sta

y a

head

–P

ull t

og

eth

er

so

me q

uesti

on

s–

Revie

w w

hat

yo

u’v

e r

ead

aft

er

the lectu

re

•L

ab

Sta

rts N

EX

T W

EE

K

Co

urs

e O

utl

ine 2

007

•W

eek 1

Lo

gic

Ga

tes

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--•

Week 2

TT

L 2

Bo

ole

an A

lge

bra

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--•

Week 3

Syste

m

K-M

ap

s

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--

•W

eek 4

Bou

nce

Mu

lti-

level C

ircu

its

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--

•W

eek 5

Add

ers

M

ulti-

leve

l C

ircu

its

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--

•W

eek 6

Shift-

Add

A

dd

ers

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--

•F

IRS

T E

XA

M,

Fe

bru

ary

22

in

cla

ss

•W

eek 7

Boa

rd C

lock 5

Mu

ltip

liers

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--•

Week 8

Mu

ltip

lier

6 M

ultip

lexe

rs,

Deco

de

rs, e

tc.

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--

•W

eek 9

8 P

rio

rity

En

co

de

r 8

Syn

ch

rono

us S

equ

ential C

kts

•S

EC

ON

D E

XA

M,

Ma

rch

23

, in

cla

ss

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--•

Week 1

0 T

-Bir

d 8

Syn

ch

rono

us S

equ

ential C

kts

.

•T

ail

Lig

hts

•W

eek 1

1 S

ynch

ron

ous S

eq

uen

tial C

kts

.•

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

•W

eek 1

2 L

ED

7 F

lip-f

lop

s

Pin

g-p

ong

•W

eek 1

3 C

ou

nte

rs

•W

eek 1

4 N

MO

S a

nd

CM

OS

Lo

gic

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--•

--T

HIR

D E

XA

M,

Ap

ril

26

•--

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

--

Read

ing

Lis

t•

Chap

ter

1 R

ead

on

lyH

igh

-le

ve

l in

trodu

ction

•C

hap

ter

2

•2

.1 –

2.7

Rea

d a

nd

Stu

dy

Fu

nd

am

en

tals

of

Co

mb

ina

tio

na

l L

og

ic D

es

ign

•2

.8 –

2.9

Read

on

lyC

AD

To

ols

and

VH

DL

•C

hap

ter

4

•4

.1 –

4.8

Rea

d a

nd

Stu

dy

Ka

rna

ug

hM

ap

s a

nd

Mu

lti-

leve

l lo

gic

cir

cu

its

•4

.9 –

4.1

2 R

ead

on

lyC

ub

es a

nd

CA

D to

ols

•C

hap

ter

5

•5

.1 –

5.4

Rea

d a

nd

Stu

dy

Lo

gic

cir

cu

its

fo

r a

dd

itio

n

•5

.5 R

ead

on

lyC

AD

Too

ls

•5

.6 –

5.8

Rea

d a

nd

Stu

dy

Mu

ltip

lic

ati

on

an

d o

the

r d

ata

re

pre

se

nta

tio

ns

•C

hap

ter

6

•6

.1 –

6.5

Rea

d a

nd

Stu

dy

MS

I le

ve

l lo

gic

pri

mit

ive

s•

6.6

Read

on

lyV

HD

L lang

uage

•C

hap

ter

8

•8

.1 –

8.3

Rea

d a

nd

Stu

dy

Ba

sic

Syn

ch

ron

ou

s S

eq

ue

nti

al

Cir

cu

it D

es

ign

•8

.4 R

ead

on

lyC

AD

tools

•8

.5.1

–8

.5.2

Re

ad

an

d S

tud

yM

ea

ly a

nd

Mo

ore

Seri

al

Ad

de

rs

•8

.5.3

–8

.6 R

ead

on

lyV

HD

L a

nd

sta

te m

inim

iza

tio

n

•8

.7 –

8.9

Rea

d a

nd

Stu

dy

De

sig

n E

xam

ple

s a

nd

An

aly

sis

Me

tho

ds

•8

.10

–8

.11

Rea

d o

nly

Alg

orith

mic

Sta

te M

ach

ine

s

•C

hap

ter

7

•7

.1 –

7.1

1 R

ea

d a

nd

Stu

dy

La

tch

es

, F

lip

-flo

ps

, R

eg

iste

rs,

an

d C

ou

nte

rs

•7

.12

–7

.14

Rea

d o

nly

CA

D t

oo

ls a

nd

VH

DL

•C

hap

ter

3

•3

.1 –

3.3

Rea

d a

nd

Stu

dy

NM

OS

an

d C

MO

S t

ran

sis

tor

sw

itc

hes

•3

.4 –

3.8

Read

on

lyIm

ple

me

nta

tion

de

tails

•3

.9 R

ea

d a

nd

Stu

dy

Tra

ns

mis

sio

n g

ate

s

•3

.10

Read

on

lyIm

ple

me

nta

tion

de

tails

Befo

re W

e B

eg

in..

•N

um

ber

Sys

tem

an

d L

og

ic–

Recall w

hen

yo

u w

ere

a k

id (

were

yo

u?

)

»L

earn

ing

ho

w t

o c

ou

nt

»T

ree

»T

ree R

easo

nin

g

»T

hin

kin

g lo

gic

all

y <

om

it u

ncert

ain

titi

es>

•L

og

ic D

esig

n–

As

str

aig

ht

forw

ard

as i

t g

ets

–F

or

sim

ple

min

ds

–W

hen

do

ne w

ith

th

is c

lass,

yo

u’l

l m

as

ter

90

% d

esig

n m

eth

od

olo

gie

s

•A

dvan

ced

Desig

n Issu

es

–C

AD

–S

pecif

ica

tio

n

–V

eri

fica

tio

n

–T

esti

ng

–F

ab

rica

tio

n

–M

ark

eti

ng

We w

ill le

arn

in

EL

EN

248 …

Lo

gic

Ga

tes

an

d B

oo

lea

n A

lge

bra

Co

mb

ina

tio

na

l L

og

ic

Ari

thm

eti

c C

irc

uit

s a

nd

Co

mm

on

MS

I L

og

ic

Cir

cu

its

Syn

ch

ron

ou

s S

eq

ue

nti

al

Cir

cu

it D

es

ign

La

tch

es

, F

lip

-flo

ps

, R

eg

iste

rs,

an

d C

ou

nte

rs

NM

OS

an

d C

MO

S-B

as

ed

Lo

gic

Ga

tes

Co

mp

ute

r O

rga

niz

ati

on

Wh

at

is lo

gic

desig

n?

•D

esig

n issu

es

–G

iven

a s

pecif

icati

on

, d

eri

ve

a s

olu

tio

n u

sin

g a

vail

ab

le c

om

po

nen

ts

–W

hil

e m

eeti

ng

cri

teri

a f

or

siz

e,

co

st,

po

wer,

beau

ty,

ele

gan

ce,

etc

.

•W

hat

is lo

gic

desig

n?

–C

ho

ose d

igit

al

log

ic c

om

po

nen

ts t

o p

erf

orm

sp

ecif

ied

co

ntr

ol, d

ata

m

an

ipu

lati

on

, o

r co

mm

un

icati

on

fu

ncti

on

an

d t

heir

in

terc

on

necti

on

–W

hic

h lo

gic

co

mp

on

en

ts t

o c

ho

ose?

Man

y i

mp

lem

en

tati

on

tech

no

log

ies (

fixed

-fu

ncti

on

co

mp

on

en

ts,

pro

gra

mm

ab

le d

evic

es,

ind

ivid

ual

tran

sis

tors

on

a c

hip

, etc

.)

–D

esig

n o

pti

miz

ed

/tra

nsfo

rmed

to

meet

desig

n c

on

str

ain

ts

close switch (if A is “1” or asserted)

and turn on light bulb (Z)

AZ

open switch (if A is “0” or unasserted)

and turn off light bulb (Z)

Sw

itch

es:

basic

ele

men

t o

f p

hysic

al

log

ic im

ple

men

tati

on

s

•Im

ple

men

tin

g a

sim

ple

cir

cu

it (

arr

ow

sh

ow

s a

cti

on

if

wir

e c

han

ges t

o “

1”):

Z

≡A

AZ

AND

OR

Z ≡

A andB

Z ≡

A orB

AB

A

B

Co

mp

uti

ng

wit

h S

wit

ch

es

•C

om

po

se s

wit

ch

es in

to m

ore

co

mp

lex (B

oo

lean

) fu

ncti

on

s:

Tw

o f

un

dam

en

tal

str

uctu

res:

seri

es (

AN

D)

an

d p

ara

llel

(OR

)

inputs

outputs

system

Co

mb

inati

on

al

vs. seq

uen

tial d

igit

al

cir

cu

its

•S

imp

le m

od

el

of

a d

igit

al

syste

m i

s a

un

it w

ith

in

pu

ts a

nd

ou

tpu

ts:

•C

om

bin

ati

on

al

mean

s "

mem

ory

-les

s"

–d

igit

al cir

cu

it is c

om

bin

ati

on

al

if i

ts o

utp

ut

valu

es

on

ly d

ep

en

d o

n i

ts in

pu

ts

easy to implement

with CMOS transistors

(the switches we have

available and use most)

Co

mb

inati

on

al lo

gic

sym

bo

ls

•C

om

mo

n c

om

bin

ati

on

al lo

gic

syste

ms h

ave

sta

nd

ard

sym

bo

ls c

alled

lo

gic

gate

s

–B

uff

er,

NO

T

–A

ND

, N

AN

D

–O

R,

NO

RZ

A BZ Z

A A B

Seq

uen

tial lo

gic

•S

eq

uen

tial s

yste

ms

–E

xh

ibit

beh

avio

rs (

ou

tpu

t va

lues)

that

dep

en

d

on

cu

rren

t as w

ell

as

pre

vio

us i

np

uts

•A

ll r

eal

cir

cu

its a

re s

eq

uen

tial

–O

utp

uts

do

no

t ch

an

ge in

sta

nta

neo

usly

aft

er

an

in

pu

t ch

an

ge

–W

hy n

ot,

an

d w

hy i

s i

t th

en

seq

uen

tial?

•F

un

dam

en

tal

ab

str

acti

on

of

dig

ital d

esig

n is t

o r

easo

n

(mo

stl

y)

ab

ou

t ste

ad

y-s

tate

beh

avio

rs–

Exam

ine o

utp

uts

on

ly a

fter

su

ffic

ien

t ti

me h

as e

lap

sed

fo

r th

e

syste

m t

o m

ake i

ts r

eq

uir

ed

ch

an

ges a

nd

sett

le d

ow

n

Syn

ch

ron

ou

s s

eq

uen

tial d

igit

al

syste

ms

•C

om

bin

ati

on

al

cir

cu

it o

utp

uts

dep

en

d o

nly

on

cu

rren

t in

pu

ts–

Aft

er

su

ffic

ien

t ti

me h

as e

lap

sed

•S

eq

uen

tial cir

cu

its h

ave m

em

ory

–E

ven

aft

er

wait

ing

fo

r tr

an

sie

nt

acti

vit

y t

o f

inis

h

•S

tead

y-s

tate

ab

str

acti

on

: m

ost

desig

ners

use i

t w

hen

co

nstr

ucti

ng

seq

uen

tial cir

cu

its:

–M

em

ory

of

syste

m i

s i

ts s

tate

–C

han

ges i

n s

yste

m s

tate

on

ly a

llo

wed

at

sp

ecif

ic t

imes

co

ntr

oll

ed

by a

n e

xte

rnal

peri

od

ic s

ign

al

(th

e c

lock)

–C

lock p

eri

od

is e

lap

sed

tim

e b

etw

een

sta

te c

han

ges

su

ffic

ien

tly l

on

g s

o t

hat

sys

tem

rea

ch

es s

tead

y-s

tate

befo

re

next

sta

te c

ha

ng

e a

t en

d o

f p

eri

od

Wh

at

makes D

igit

al S

yste

ms t

ick?

Co

mb

ina

tio

nal

Lo

gic

tim

e

clk

Le

t’s

go

ba

ck

an

d R

em

em

be

r th

e n

um

be

r s

ys

tem

s..

•B

inary

vari

ab

les ju

st

like o

ther

vari

ab

les w

e k

no

w

of…

uh

.. It’

s t

he s

am

e!

–B

inary

vari

ab

les a

re a

“cla

ss” o

f g

en

era

l va

riab

les

–E

xam

ple

: A

po

inte

r o

r co

nta

iner

of

field

•O

pera

tio

ns?

E

xp

ressio

ns o

f o

pera

tio

ns?

–A

rith

meti

c o

pera

tio

ns

»X

= y

+ 1

y =

1x =

10

etc

–L

og

ical/

Bin

ary

/Bo

ole

an

op

era

tio

ns

X =

Y +

1+

..is

“O

R”

x..is

“A

ND

Y =

1X

= Y

1 =

1 +

..u

h

XY

Z0

00

01

01

00

11

1

XY

01

10

XY

Z0

00

01

11

01

11

1

XY

X XY Y

Z Z

Bo

ole

an

ex

pre

ss

ion

s a

nd

lo

gic

ga

tes

•N

OT

X'

X~

X S

ym

bo

l T

ruth

Tab

le

•A

ND

X •

YX

YX

+Y

•O

RX

+ Y

X +

Y

X YZ

XY

Z0

01

01

11

01

11

0

XY

Z0

01

01

01

00

11

0

ZX Y X Y

Z

XY

Z0

01

01

01

00

11

1

XY

Z0

00

01

11

01

11

0

ZX Y

X xorY = X Y' + X' Y

X or Y but not both

("inequality", "difference")

X xnorY = X Y + X' Y'

X and Y are the same

("equality", "coincidence")

Bo

ole

an

exp

ressio

ns a

nd

lo

gic

gate

s

•N

AN

D

•N

OR

•X

OR

X ⊕

Y

•X

NO

RX

= Y

T1T2

use of 3-input gate

A B C DT2

T1

ZA B C D

Z

Bo

ole

an

exp

ressio

ns a

nd

lo

gic

gate

s

•M

ore

th

an

on

e w

ay t

o m

ap

exp

ressio

ns t

o g

ate

s

–e.g

., Z

= A

' •

B' •

(C +

D)

= (

A' •

(B' •

(C +

D))

)

Desig

n R

ep

resen

tati

on

Tru

th T

able

Bo

ole

anE

xpre

ssio

n

gat

ere

pre

sen

tati

on

(sc

hem

atic

)

??

uniq

ue

not

uniq

ue

not

uniq

ue

[conven

ient fo

r m

anip

ula

tion]

[clo

se to

imple

men

tato

n]

Fo

r a g

ive

n f

un

cti

on

, th

ere

is O

NE

un

iqu

e t

ruth

tab

le. H

ow

ever,

th

ere

m

ay b

e m

ore

th

an

on

e b

oo

lean

exp

ressio

n o

r th

e g

ate

desig

n

XY

X nandY

00

1

11

0

XY

X nor Y

00

1

11

0

X n

and

Y≡

not

( (

not

X)

nor

(not

Y)

)

X n

or

Y≡

not

( (n

ot

X)

na

nd

(not

Y)

)

Min

imal set

of

fun

cti

on

s

•Im

ple

men

t an

y l

og

ic f

un

cti

on

s f

rom

NO

T, N

OR

, an

d

NA

ND

?

–F

or

exam

ple

, im

ple

men

tin

g

X

an

dY

is t

he s

am

e a

s i

mp

lem

en

tin

g

no

t(X

nan

dY

)

•D

o i

t w

ith

on

ly N

OR

or

on

ly N

AN

D

–N

OT

is ju

st

a N

AN

D o

r a N

OR

wit

h b

oth

in

pu

ts t

ied

to

geth

er

–an

d N

AN

D a

nd

NO

R a

re "

du

als

", i.e

., e

asy t

o i

mp

lem

en

t o

ne u

sin

g

the o

ther

•B

ased

on

th

e m

ath

em

ati

cal fo

un

dati

on

s o

f lo

gic

: B

oo

lean

Alg

eb

ra

An

alg

eb

raic

str

uctu

re

•A

n a

lge

bra

ic s

tru

ctu

re c

on

sis

ts o

f–

a s

et

of

ele

men

ts B

–b

inary

op

era

tio

ns {

+ , •

}

–an

d a

un

ary

op

era

tio

n {

' }

–su

ch

th

at

the f

ollo

win

g a

xio

ms h

old

:

1. set

B c

on

tain

s a

t le

ast

two

ele

men

ts, a, b

, su

ch

th

at

a ≠ ≠≠≠

b2. clo

su

re:

a +

b is in

Ba •

b is in

B3. co

mm

uta

tivit

y:

a +

b =

b +

aa •

b =

b •

a4. asso

cia

tivit

y:

a +

(b

+ c

) =

(a +

b)

+ c

a •

(b

• c

) =

(a •

b)

• c

5. id

en

tity

:a +

0 =

aa •

1 =

a6. d

istr

ibu

tivit

y:

a +

(b

• c

) =

(a +

b)

• (a

+ c

) a •

(b

+ c

) =

(a •

b)

+ (

a •

c)

7. co

mp

lem

en

tari

ty:

a +

a' =

1a •

a' =

0

Bo

ole

an

alg

eb

ra

•B

oo

lean

alg

eb

ra–

B =

{0,

1}

–+

is lo

gic

al

OR

, •

is lo

gic

al A

ND

–' is

lo

gic

al

NO

T

•A

ll a

lgeb

raic

axio

ms h

old

X, Y are Boolean algebra variables

XY

X •Y

00

00

10

10

01

11

XY

X'

Y'

X •Y

X' •Y'( X •Y ) + ( X' •Y' )

00

11

01

10

11

00

00

10

01

00

01

10

01

01

( X •Y ) + ( X' •Y' ) ≡

X =Y

XY

X'

X' • Y

00

10

01

11

10

00

11

00

Boolean expression that is

true when the variables X

and Y have the same value

and false, otherwise

Lo

gic

fu

nc

tio

ns

an

d B

oo

lea

n a

lge

bra

•A

ny l

og

ic f

un

cti

on

th

at

can

be e

xp

ress

ed

as a

tr

uth

tab

le c

an

be w

ritt

en

as a

n e

xp

ressio

n in

B

oo

lean

alg

eb

ra u

sin

g t

he o

pera

tors

: ', +

, an

d •

XY

16 possible functions (F0–F15)

00

00

00

00

00

11

11

11

11

01

00

00

11

11

00

00

11

11

10

00

11

00

11

00

11

00

11

11

01

01

01

01

01

01

01

01

X YF

XY

X norY

not(X orY)

X nandY

not(X andY)

10

notX

X andY

X orY

notY

X xorY

X =

Y

Po

ssib

le lo

gic

fu

ncti

on

s o

f tw

o v

ari

ab

les

•16 p

ossib

le f

un

cti

on

s o

f 2 in

pu

t vari

ab

les:

–2**

(2**

n)

fun

cti

on

s o

f n

in

pu

ts

Axio

ms &

th

eo

rem

s o

f B

oo

lean

alg

eb

ra

•Id

en

tity

1. X

+ 0

= X

1D

. X

• 1

= X

•N

ull 2. X

+ 1

= 1

2D

. X

• 0

= 0

•Id

em

po

ten

cy:

3. X

+ X

= X

3D

. X

• X

= X

•In

vo

luti

on

:4. (X

')' =

X

•C

om

ple

me

nta

rity

:5. X

+ X

' =

15D

. X

• X

' =

0

•C

om

mu

tati

vit

y:

6. X

+ Y

= Y

+ X

6D

. X

• Y

= Y

• X

•A

sso

cia

tivit

y:

7. (X

+ Y

) +

Z =

X +

(Y

+ Z

)7D

. (X

• Y

) •

Z =

X •

(Y

• Z

)

Axio

ms a

nd

th

eo

rem

s o

f B

oo

lean

alg

eb

ra

(co

nt’

d)

•D

istr

ibu

tivit

y:

8. X

• (

Y +

Z)

= (

X •

Y)

+ (

X •

Z)

8D

. X

+ (

Y •

Z)

= (

X +

Y)

• (X

+ Z

)

•U

nit

ing

:9. X

• Y

+ X

• Y

' =

X9D

. (X

+ Y

) •

(X +

Y')

= X

•A

bso

rpti

on

:10. X

+ X

• Y

= X

10D

. X

• (

X +

Y)

= X

11. (X

+ Y

') •

Y =

X •

Y11D

. (

X •

Y')

+ Y

= X

+ Y

•F

acto

rin

g:

12. (X

+ Y

) •

(X' +

Z)

=12D

. X

• Y

+ X

' •

Z =

X

• Z

+ X

' •

Y(X

+ Z

) •

(X' +

Y)

•C

on

cen

su

s:

13. (X

• Y

) +

(Y

• Z

) +

(X

' •

Z)

=

13D

. (X

+ Y

) •

(Y +

Z)

• (X

' +

Z)

=X

• Y

+ X

' •

Z(X

+ Y

) •

(X' +

Z)

Axio

ms a

nd

th

eo

rem

s o

f B

oo

lean

alg

eb

ra

(co

nt’

)

•d

e M

org

an

's:

14. (X

+ Y

+ ...)'

= X

' •

Y' •

...

14D

. (X

• Y

• ...)'

= X

' +

Y'

+ ...

•g

en

era

lized

de M

org

an

's:

15. f'

(X1,X

2,...,X

n,0

,1,+

,•)

= f(

X1',X

2',...,X

n',1,0

,•,+

)

•esta

bli

sh

es r

ela

tio

nsh

ip b

etw

een

• a

nd

+

Axio

ms &

th

eo

rem

s o

f B

oo

l. A

lg. -

Du

ality

•D

uali

ty–

Du

al

of

a B

oo

lean

exp

res

sio

n i

s d

eri

ved

by r

ep

lacin

g •

by +

, +

by •

, 0 b

y 1

, an

d 1

by 0

, an

d l

ea

vin

g v

ari

ab

les u

nch

an

ged

–A

ny t

heo

rem

th

at

can

be p

roven

is t

hu

s a

lso

pro

ven

fo

r it

s d

ual!

–M

eta

-th

eo

rem

(a t

heo

rem

ab

ou

t th

eo

rem

s)

•d

uality

:16. X

+ Y

+ ... ⇔ ⇔⇔⇔

X •

Y •

...

•g

en

era

lized

du

ality

:17. f

(X1,X

2,...,X

n,0

,1,+

,•)

⇔ ⇔⇔⇔f(

X1,X

2,...,X

n,1

,0,•

,+)

•D

iffe

ren

t th

an

deM

org

an

’sL

aw

–th

is i

s a

sta

tem

en

t ab

ou

t th

eo

rem

s

–th

is i

s n

ot

a w

ay t

o m

an

ipu

late

(re

-wri

te)

exp

res

sio

ns

Pro

vin

g t

heo

rem

s (

rew

riti

ng

)

•U

sin

g t

he a

xio

ms o

f B

oo

lean

alg

eb

ra:

–e.g

., p

rove t

he

th

eo

rem

: X

• Y

+ X

• Y

' =

X

–e.g

., p

rove t

he

th

eo

rem

: X

+ X

• Y

=

X

distributivity(8)

X •Y + X •Y'

= X • (Y + Y')

complementarity(5)

X • (Y + Y')

= X •(1)

identity (1D)

X •(1)

= X �

identity (1D)

X + X • Y

= X • 1 + X • Y

distributivity(8)

X • 1 + X • Y

= X • (1 + Y)

identity (2)

X • (1 + Y)

= X •(1)

identity (1D)

X • (1)

= X �

(X + Y)' = X' • Y'

NOR is equivalent to AND

with inputs complemented

(X • Y)' = X' + Y'

NAND is equivalent to OR

with inputs complemented

XY

X'Y'

(X + Y)'

X' • Y'

00

11

01

10

10

01

11

00

XY

X'Y'

(X • Y)'

X' + Y'

00

11

01

10

10

01

11

00

Pro

vin

g t

heo

rem

s (

perf

ect

ind

ucti

on

)•

De M

org

an

’s L

aw

–co

mp

lete

tru

th t

ab

le,

exh

au

sti

ve p

roo

f

1 0 0 0 1 1 1 0

1 0 0 0 1 1 1 0

=

=

Pu

sh

in

v.

bu

bb

le f

rom

ou

tpu

t to

in

pu

t an

d c

han

ge s

ym

bo

l

A s

imp

le e

xam

ple

•1-b

it b

inary

ad

der

–in

pu

ts:

A,

B,

Carr

y-i

n

–o

utp

uts

: S

um

, C

arr

y-o

ut

A B

Cin

Cout

S

AB

CinS

Cout

00

00

01

01

00

11

10

01

01

11

01

11

0 1 1 0 1 0 0 1

0 0 0 1 0 1 1 1

Cout= A' B Cin+ A B' Cin+ A B Cin' + A B Cin

S = A' B' Cin+ A' B Cin' + A B' Cin' + A B Cin

Ap

ply

th

e t

heo

rem

s t

o s

imp

lify

exp

ressio

ns

•T

he t

heo

rem

s o

f B

oo

lean

alg

eb

ra c

an

sim

plify

B

oo

lean

exp

res

sio

ns

–e.g

., f

ull a

dd

er'

s c

arr

y-o

ut

fun

cti

on

(sam

e r

ule

s a

pp

ly t

o a

ny

fun

cti

on

)

Cout

= A' B Cin+ A B' Cin+ A B Cin' + A B Cin

= A' B Cin+ A B' Cin+ A B Cin' + A B Cin

+ A B Cin

= A' B Cin+ A B Cin

+ A B' Cin+ A B Cin' + A B Cin

= (A' + A) B Cin

+ A B' Cin+ A B Cin' + A B Cin

= (1)B Cin

+ A B' Cin+ A B Cin' + A B Cin

= B Cin

+ A B' Cin+ A B Cin' + A B Cin+ A B Cin

= B Cin+ A B' Cin+ A B Cin+ A B Cin' + A B Cin

= B Cin+ A (B' + B) Cin

+ A B Cin' + A B Cin

= B Cin+ A (1) Cin

+ A B Cin' + A B Cin

= B Cin+ A Cin+ A B (Cin' + Cin)

= B Cin+ A Cin+ A B (1)

= B Cin+ A Cin+ A B

time

change in Y takes time to "propagate" through gates

Wavefo

rm v

iew

of

log

ic f

un

cti

on

s

•Ju

st

a s

idew

ays t

ruth

tab

le–

bu

t n

ote

ho

w e

dg

es d

on

't lin

e u

p e

xactl

y

–it

takes t

ime f

or

a g

ate

to

sw

itch

its

ou

tpu

t!

AB

CZ

00

00

00

11

01

00

01

11

10

00

10

11

11

01

11

10

Ch

oo

sin

g d

iffe

ren

t re

alizati

on

s o

f a

fun

cti

on

two-level realization

(we don't count NOT gates)

XOR gate (easier to draw

but costlier to build)

multi-level realization

(gates with fewer inputs)

Wh

ich

realizati

on

is b

est?

•R

ed

uc

e n

um

ber

of

inp

uts

–li

tera

l: i

np

ut

vari

ab

le (

co

mp

lem

en

ted

or

no

t)

»can

ap

pro

xim

ate

co

st

of

log

ic g

ate

as 2

tra

nsis

tors

per

lite

ral

»w

hy n

ot

co

un

t in

vert

ers

?

–F

ew

er

lite

rals

mean

s l

ess t

ran

sis

tors

»sm

all

er

cir

cu

its

–F

ew

er

inp

uts

im

pli

es f

aste

r g

ate

s

»g

ate

s a

re s

ma

ller

an

d t

hu

s a

lso

faste

r

–F

an

-in

s (

# o

f g

ate

in

pu

ts)

are

lim

ited

in

so

me t

ech

no

log

ies

•R

ed

uc

e n

um

ber

of

gate

s–

Few

er

gate

s (

an

d t

he p

ackag

es t

hey c

om

e i

n)

mean

s s

mall

er

cir

cu

its

»d

irectl

y i

nfl

uen

ces m

an

ufa

ctu

rin

g c

osts

Wh

ich

is t

he b

est

realizati

on

?

(co

nt’

d)

•R

ed

uc

e n

um

ber

of

levels

of

gate

s–

Few

er

level

of

gate

s i

mp

lies r

ed

uced

sig

nal

pro

pag

ati

on

d

ela

ys

–M

inim

um

dela

y c

on

fig

ura

tio

n t

yp

icall

y r

eq

uir

es m

ore

gate

s

»w

ider,

less d

eep

cir

cu

its

•H

ow

do

we e

xp

lore

tra

deo

ffs b

etw

een

in

cre

as

ed

cir

cu

it d

ela

y a

nd

siz

e?

–A

uto

mate

d t

oo

ls t

o g

en

era

te d

iffe

ren

t so

luti

on

s

–L

og

ic m

inim

izati

on

: re

du

ce n

um

ber

of

gate

s a

nd

co

mp

lexit

y

–L

og

ic o

pti

miz

ati

on

: re

du

cti

on

wh

ile t

rad

ing

off

ag

ain

st

dela

y

Are

all r

ealizati

on

s e

qu

ivale

nt?

•U

nd

er

the s

am

e i

np

uts

, th

e a

ltern

ati

ve i

mp

lem

en

tati

on

s

have a

lmo

st

the s

am

e w

avefo

rm b

eh

avio

r–

dela

ys a

re d

iffe

ren

t

–g

litc

hes (

hazard

s)

ma

y a

ris

e

–va

riati

on

s d

ue t

o d

iffe

ren

ce

s i

n n

um

ber

of

gate

le

vels

an

d s

tru

ctu

re

•T

hre

e i

mp

lem

en

tati

on

s a

re f

un

cti

on

ally e

qu

ivale

nt

Imp

lem

en

tin

g B

oo

lean

fu

ncti

on

s

•T

ech

no

log

y i

nd

ep

en

den

t–

Can

on

ical

form

s

–T

wo

-le

vel

form

s

–M

ult

i-le

vel

form

s

•T

ech

no

log

y c

ho

ices

–P

ackag

es o

f a f

ew

gate

s

–R

eg

ula

r lo

gic

–T

wo

-le

vel

pro

gra

mm

ab

le l

og

ic

–M

ult

i-le

vel

pro

gra

mm

ab

le l

og

ic

Can

on

ical fo

rms

•T

ruth

tab

le i

s t

he u

niq

ue s

ign

atu

re o

f a B

oo

lean

fu

ncti

on

•M

an

y a

ltern

ati

ve g

ate

reali

zati

on

s m

ay h

ave t

he

sam

e t

ruth

tab

le

•C

an

on

ical fo

rms

–S

tan

dard

fo

rms f

or

a B

oo

lean

exp

res

sio

n

–P

rovid

es a

un

iqu

e a

lgeb

raic

sig

natu

re

AB

CF

F'

00

00

10

01

10

01

00

10

11

10

10

00

11

01

10

11

01

01

11

10

F = F' = A'B'C' + A'BC' + AB'C'

Su

m-o

f-p

rod

ucts

can

on

ical fo

rms

•A

lso

kn

ow

n a

s d

isju

ncti

ve n

orm

al

form

•A

lso

kn

ow

n a

s m

inte

rmexp

an

sio

n

F = 001 011 101 110 111

+ A'BC+ AB'C+ ABC'+ ABC

A'B'C

short-hand notation for

mintermsof 3 variables

AB

Cminterms

00

0A'B'C'm0

00

1A'B'C

m1

01

0A'BC'm2

01

1A'BC

m3

10

0AB'C'm4

10

1AB'C

m5

11

0ABC'm6

11

1ABC

m7

F in canonical form

:

F(A, B, C)=

Σm(1,3,5,6,7)

= m1 + m3 + m5 + m6 + m7

= A'B'C + A'BC + AB'C + ABC' + ABC

canonical form

≠minimal form

F(A, B, C)= A'B'C + A'BC + AB'C + ABC + ABC'

= (A'B' + A'B + AB' + AB)C + ABC'

= ((A' + A)(B' + B))C + ABC'

= C + ABC'

= ABC' + C

= AB + C

Su

m-o

f-p

rod

uc

ts c

an

on

ica

l fo

rm (

co

nt’

d)

•P

rod

uct

term

(o

r m

inte

rm)

–A

ND

ed

pro

du

ct

of

lite

rals

–in

pu

t co

mb

inati

on

fo

r w

hic

h o

utp

ut

is t

rue

–E

ach

va

riab

le a

pp

ears

ex

actl

y o

nce,

in t

rue o

r in

vert

ed

fo

rm (

bu

t n

ot

bo

th)

AB

CF

F'

00

00

10

01

10

01

00

10

11

10

10

00

11

01

10

11

01

01

11

10

F = 000 010 100

F =

F' = (A +

B +

C') (A +

B' + C') (A' + B +

C') (A' + B' + C) (A' + B' + C')

Pro

du

ct-

of-

su

ms c

an

on

ical fo

rm

•A

lso

kn

ow

n a

s c

on

jun

cti

ve n

orm

al

form

•A

lso

kn

ow

n a

s m

axte

rmexp

an

sio

n

(A + B + C)(A + B' + C)(A' + B + C)

AB

Cmaxterms

00

0A+B+C

M0

00

1A+B+C'

M1

01

0A+B'+C

M2

01

1A+B'+C'

M3

10

0A'+B+C

M4

10

1A'+B+C'

M5

11

0A'+B'+C

M6

11

1A'+B'+C'

M7

short-hand notation for

maxtermsof 3 variables

F in canonical form:

F(A, B, C)=

ΠM(0,2,4)

= M0 • M2 • M4

= (A + B + C) (A + B' + C) (A' + B + C)

canonical form

≠minimal form

F(A, B, C)= (A + B + C) (A + B' + C) (A' + B + C)

= (A + B + C) (A + B' + C)

(A + B + C) (A' + B + C)

= (A + C) (B + C)

Pro

du

ct-

of-

su

ms c

an

on

ical fo

rm (

co

nt’

d)

•S

um

term

(o

r m

axte

rm)

–O

Red

su

m o

f lite

rals

–in

pu

t co

mb

inati

on

fo

r w

hic

h o

utp

ut

is f

als

e

–each

vari

ab

le a

pp

ears

ex

actl

y o

nce,

in t

rue o

r in

vert

ed

fo

rm (

bu

t n

ot

bo

th)

S-o

-P, P

-o-S

, an

d d

e M

org

an

’s t

heo

rem

•S

um

-of-

pro

du

cts

–F

' =

A'B

'C' +

A'B

C' +

AB

'C'

•A

pp

ly d

e M

org

an

's–

(F')

' =

(A

'B'C

' +

A'B

C' +

AB

'C')

'

–F

= (

A +

B +

C)

(A +

B' +

C)

(A' +

B +

C)

•P

rod

uct-

of-

su

ms

–F

' =

(A

+ B

+ C

') (

A +

B' +

C')

(A

' +

B +

C')

(A

' +

B' +

C)

(A' +

B' +

C')

•A

pp

ly d

e M

org

an

's–

(F')

' =

( (

A +

B +

C')

(A +

B' +

C')

(A' +

B +

C')

(A' +

B' +

C)(

A'+

B' +

C')

)'

–F

= A

'B'C

+ A

'BC

+ A

B'C

+ A

BC

' +

AB

C

canonical sum-of-products

minimized sum-of-products

canonical product-of-sums

minimized product-of-sums

F1

F2

F3

BA C

F4

Fo

ur

alt

ern

ati

ve t

wo

-level im

ple

men

tati

on

so

f F

= A

B +

C

Wavefo

rms f

or

the f

ou

r alt

ern

ati

ves

•W

avefo

rms a

re e

ss

en

tiall

y i

den

tical

–E

xcep

t fo

r ti

min

g h

azard

s (

gli

tch

es)

–D

ela

ys a

lmo

st

iden

tical

(mo

dele

d a

s a

dela

y p

er

level,

no

t ty

pe

of

gate

or

nu

mb

er

of

inp

uts

to

gate

)

Map

pin

g b

etw

een

can

on

ical fo

rms

•M

inte

rmto

maxte

rmco

nvers

ion

–U

se m

axte

rms

wh

ose i

nd

ices d

o n

ot

ap

pear

in m

inte

rmexp

an

sio

n

–e.g

., F

(A,B

,C)

= Σ ΣΣΣ

m(1

,3,5

,6,7

) =

Π ΠΠΠM

(0,2

,4)

•M

axte

rmto

min

term

co

nvers

ion

–U

se m

inte

rms

wh

ose in

dic

es d

o n

ot

ap

pear

in m

axte

rmexp

an

sio

n

–e.g

., F

(A,B

,C)

= Π ΠΠΠ

M(0

,2,4

) =

Σ ΣΣΣm

(1,3

,5,6

,7)

•M

inte

rmexp

an

sio

n o

f F

to

min

term

exp

an

sio

n o

f F

'–

Use m

inte

rms

wh

ose in

dic

es d

o n

ot

ap

pear

–e.g

., F

(A,B

,C)

= Σ ΣΣΣ

m(1

,3,5

,6,7

) F

'(A

,B,C

) =

Σ ΣΣΣm

(0,2

,4)

•M

axte

rme

xp

an

sio

n o

f F

to

maxte

rmexp

an

sio

n o

f F

'–

Use m

axte

rms

wh

ose i

nd

ices d

o n

ot

ap

pear

–e.g

., F

(A,B

,C)

= Π ΠΠΠ

M(0

,2,4

) F

'(A

,B,C

) =

Π ΠΠΠM

(1,3

,5,6

,7)

AB

CD

WX Y

Z0

00

00

00

10

00

10

01

00

01

00

01

10

01

10

10

00

10

00

10

10

10

10

11

00

11

00

11

10

11

11

00

01

00

01

00

11

00

10

00

01

01

0X

XX

X1

01

1X

XX

X1

10

0X

XX

X1

10

1X

XX

X1

11

0X

XX

X1

11

1X

XX

X

off-set of W

these inputs patterns should

never be encountered in practice

–"don't care"about associated

output values, can be exploited

in minimization

Inco

mp

lete

ley

sp

ecif

ied

fu

ncti

on

s

•E

xam

ple

: b

inary

co

ded

decim

al in

cre

men

t b

y 1

–B

CD

dig

its e

nco

de d

ecim

al

dig

its 0

–9 in

bit

patt

ern

s 0

000 –

10

01

don't care (DC) set of W

on-set of W

No

tati

on

fo

r in

co

mp

lete

ly s

pecif

ied

fu

ncti

on

s

•D

on

't c

are

s a

nd

can

on

ical fo

rms

–S

o f

ar,

on

ly r

ep

resen

ted

on

-set

–A

lso

rep

resen

t d

on

't-c

are

-set

–N

eed

tw

o o

f th

e t

hre

e s

ets

(o

n-s

et,

off

-set,

dc-s

et)

•C

an

on

ical re

pre

sen

tati

on

s o

f th

e B

CD

in

cre

men

t b

y 1

fu

ncti

on

:

–Z

= m

0 +

m2 +

m4 +

m6 +

m8 +

d10 +

d11 +

d12 +

d13 +

d14 +

d15

–Z

= Σ ΣΣΣ

[ m

(0,2

,4,6

,8)

+ d

(10,1

1,1

2,1

3,1

4,1

5)

]

–Z

= M

1 •

M3 •

M5 •

M7 •

M9 •

D10 •

D11 •

D12 •

D13 •

D14 •

D15

–Z

= Π ΠΠΠ

[ M

(1,3

,5,7

,9)

• D

(10,1

1,1

2,1

3,1

4,1

5)

]

Sim

plifi

cati

on

of

two

-level co

mb

. lo

gic

•F

ind

ing

a m

inim

al su

m o

f p

rod

ucts

or

pro

du

ct

of

su

ms r

eali

zati

on

–E

xp

loit

do

n't

care

in

form

ati

on

in

th

e p

rocess

•A

lgeb

raic

sim

plifi

cati

on

–N

ot

an

alg

ori

thm

ic/s

yste

ma

tic p

roced

ure

–H

ow

do

yo

u k

no

w w

hen

th

e m

inim

um

reali

zati

on

has b

een

fo

un

d?

•C

om

pu

ter-

aid

ed

desig

n t

oo

ls–

Pre

cis

e s

olu

tio

ns r

eq

uir

e v

ery

lo

ng

co

mp

uta

tio

n t

imes,

esp

ecia

lly

for

fun

cti

on

s w

ith

man

y i

np

uts

(>

10)

–H

eu

risti

c m

eth

od

s e

mp

loyed

–"e

du

cate

d g

uesses"

to r

ed

uce

am

ou

nt

of

co

mp

uta

tio

n a

nd

yie

ld g

oo

d i

f n

ot

best

so

luti

on

s

•H

an

d m

eth

od

s s

till r

ele

van

t–

To

un

ders

tan

d a

uto

mati

c t

oo

ls a

nd

th

eir

str

en

gth

s a

nd

w

eakn

esses

–A

bil

ity t

o c

he

ck r

esu

lts (

on

sm

all

exam

ple

s)

Co

mb

inati

on

al lo

gic

su

mm

ary

•L

og

ic f

un

cti

on

s, tr

uth

tab

les,

an

d s

wit

ch

es

–N

OT

, A

ND

, O

R,

NA

ND

, N

OR

, X

OR

, . . .,

min

imal

set

•A

xio

ms a

nd

th

eo

rem

s o

f B

oo

lean

alg

eb

ra–

Pro

ofs

by r

e-w

riti

ng

an

d p

erf

ect

ind

ucti

on

•G

ate

lo

gic

–N

etw

ork

s o

f B

oo

lean

fu

ncti

on

s a

nd

th

eir

tim

e b

eh

avio

r

•C

an

on

ical fo

rms

–T

wo

-le

vel

an

d i

nco

mp

lete

ly s

pecif

ied

fu

ncti

on

s

•L

ate

r–

Tw

o-l

evel

sim

pli

ficati

on

usin

g K

-map

s

–A

uto

mati

on

of

sim

pli

ficati

on

–M

ult

i-le

vel

log

ic

–D

esig

n c

ase s

tud

ies

–T

ime b

eh

avio

r