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8/6/2019 Introduction to Digital Logic 1
http://slidepdf.com/reader/full/introduction-to-digital-logic-1 1/20
8/6/2019 Introduction to Digital Logic 1
http://slidepdf.com/reader/full/introduction-to-digital-logic-1 2/20
U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
O b j e c t i v e s
•
A f t e r t h i s l e c t u r e , y o u s h o u l d b e
a b l e t o … … .
– S t a t e t h
e 3 p o s s i b l e
a r r a n g e m e n t s o f d i g i t a
l l o g i c
– F o r m u l a t e s i m p l e e l e c t r o n i c l o g
i c g a t e f u n c
t i o n
– D e f i n e w
h a t i s m e a n t b y a t r u t h
t a b l e
– W r i t e t r u t h t a b l e s f o
r 2 - i n p u t A N
D , O R , N O T
f o r m s
– I n t e r p r e
t B o o l e a n e x p r e s s i o n s i n s o f t w a r e f o r m
– S y n t h e s
i z e c o m p o s
i t e c o m b i n a
t i o n a l f u n c t i o n s
– D e v e l o p
t r u t h t a b l e s f r o m g a t e l e v e l d i a g r a m s
– R e c o g n
i z e t h e i m p o
r t a n c e o f p o
w e r d i s s i p a
t i o n
a n d p r o
p a g a t i o n d e
l a y i n l o g i c c i r c u i t s
8/6/2019 Introduction to Digital Logic 1
http://slidepdf.com/reader/full/introduction-to-digital-logic-1 3/20
A - 3
A p p e n d i x
A - D i g i t a l L o g i c
P r i n c i p
l e s o f C o m p u t e r A r c h i t e c t u r e b
y M .
M u r d o c c a a n d V .
H e u r i n g
©
1 9 9 9 M . M u r d o c c a
a n d V . H e u r i n g
T h e C o m b i n a t
i o n a l L o
g i c U n i t
•
T r a n s l a t e s a s e t o f i n p u t s i n t o a s e t o f o u t p u t s a c c o r d i n g t o o n e o r
m o r e m a p p i n
g f u n c t i o n s .
•
I n p u t s a n d o u t p u t s f o r a C L U
n o r m a l l y h a v e t w o d i s t i n c t ( b i n
a r y )
v a l u e s : h i g h a n d l o w , 1 a n d 0
, 0 a n d 1 , o r 5 v . a n d 0 v . f o r e x a m p l e .
•
T h e o u t p u t s o f a C L U a r e s t r i c t l y f u n c t i o n s o
f t h e i n p u t s , a n d
t h e
o u t p u t s a r e u
p d a t e d i m m e d i a
t e l y a f t e r t h e i n p u t s c h a n g e . A s e t o f
i n p u t s i 0 – i n
a r e p r e s e n t e d t o t h e C L U , w h i c h p r o d u c e s a s e
t o f
o u t p u t s a c c o
r d i n g t o m a p p i n
g f u n c t i o n s f 0 –
f m
8/6/2019 Introduction to Digital Logic 1
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8/6/2019 Introduction to Digital Logic 1
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A - 5
A p p e n d i x
A - D i g i t a l L o g i c
P r i n c i p
l e s o f C o m p u t e r A r c h i t e c t u r e b
y M .
M u r d o c c a a n d V .
H e u r i n g
©
1 9 9 9 M . M u r d o c c a
a n d V . H e u r i n g
A
n o t h e r D e f i n i t i o
n … . .
•
C o m b i n a t i o n
a l l o g i c : a s y s
t e m i n w h i c h l o g i c a l d e c i s i o
n s a r e
m a d e b a s e d
o n l y o n C O M B I N A T I O N S o f
t h e C U R R E N T
I N P U T S
e . g . a n a d d e
r .
•
S e q u e n t i a l l o g i c : a s y s t e m
i n w h i c h d e c i s i o n s a r e m a d e b a s e d
o n C O M B I N A T I O N S o f t h e
C U R R E N T I N P
U T S a s w e l l a s t h e
P A S T H I S T O
R Y o f i n p u t s .
e . g . a m e m o r y
u n i t .
•
F i n i t e s t a t e m a c h i n e : i n t h i s m o d e l , l o g i c
m a i n t a i n s a n
i n t e r n a l
s t a t e ; I t s o u t p u t s a r e f u n c t
i o n s o f b o t h C
U R R E N T I N P U
T S a n d
i t s I N T E R N A
L S T A T E e . g . o f a p h y s i c a l i m p l e m e n t a t i o n
o f a
F S M i s a v e n
d i n g m a c h i n e
c o n t r o l l e r .
8/6/2019 Introduction to Digital Logic 1
http://slidepdf.com/reader/full/introduction-to-digital-logic-1 6/20
U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
M a k i n
g L o g i c G a t e
C i r c u i t s
•
W e w i l l r e v
i e w m a t e r i a
l l o c a t e d a t t h e f o l l o w i n g U R L :
h t t p : / / w w w . s p s u . e d u / c s / f a c u l t y / b b r o w n / w e b_
l e c t u r
e s / i n d e x . h t m l
•
B o b B r o w n ( S C S E S o u
t h e r n P o l y t e c h n i c S t a t e
U n i v e r s i t y ) h a s p r e p a r
e d s o m e g o o d i n t e r a c t i v e
n o t e s
•
W e w i l l r e v
i e w t h e f i r s t t w o s e c t i o n
s o f t h e “ G a t e s
C i r c u i t s a n
d D i g i t a l L o
g i c ” C h a p t e
r :
– E l e c t r i c C
i r c u i t s
– T r a n s i s t o
r s a n d D i g i t a l
L o g i c G a t e s
•
Y o u a r e e n
c o u r a g e d t o
r e - r e a d t h e
s e l a t e r a n d
t o
r e f e r t o t h e
r e l e v a n t s e
c t i o n s o f t h e c o u r s e t e x
t b o o k s
8/6/2019 Introduction to Digital Logic 1
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U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
B o o l e a n O p e r a t o r s i n
P r o g r a
m s
•
W e w
i l l n
o w
l e a r n
t o a n a
l y z e s o m e w r i t t e n
B o o
l e a n
o p e r a
t o r
s t a t e m e n
t s f r o m
t h e
p r o g r a m m e r ’ s v i e w p o
i n t
– O R f u n
c t i o n
– A N D f u
n c t i o n
– B o o l e a
n e x p r e s s i o n s
8/6/2019 Introduction to Digital Logic 1
http://slidepdf.com/reader/full/introduction-to-digital-logic-1 8/20
8/6/2019 Introduction to Digital Logic 1
http://slidepdf.com/reader/full/introduction-to-digital-logic-1 9/20
U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
B o o
l e a n A
N D O p
e r a t o r
•
L e
t ’ s l o o k a
t h o w
t h i s c o n d i
t i o n a
l
s t a t e m e n
t w o r k s
• I f ( ( x
> 0 ) & & ( x <
5 ) ) z = 2 0 ;
• A g a i n
w e a s s i g n a
v a l u e o f 7 t o v a r i a b l e x
• I f ( T R
U E & & F A L S
E ) z = 2 0 ;
• I f F A L S E z = 2 0 ;
• T h i s i s a n u l l s t a t e
m e n t
• N o v a l u e i s a s s i g n
e d t o z .
N o t h i n g h a p p e n s
.
8/6/2019 Introduction to Digital Logic 1
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U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
B o o l e
a n E x p r e s s i o
n s – A
n
E x a m p l e
•
W o r k o n
t h e
B o o l e
a n e x p r e s s
i o n
i n N
e v e
l n
o n p
3 2
8/6/2019 Introduction to Digital Logic 1
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8/6/2019 Introduction to Digital Logic 1
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U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
B
o o l e a n
N e t w o r k s
•
O U T P U T
= ( ( p A N D
q ) O R r )
– A n e x a m
p l e o f a c o m
p o s i t e f u n c t i o n w h i c h c a n
b e
s y n t h e s i z e d w i t h s i m p l e l o g i c f o r m
s { A N D ,
O R
}
U 1 S N 7 4 0 8
U 2 S N 7 4 3 2
O U T
P U T
p q r
8/6/2019 Introduction to Digital Logic 1
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U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
S y n t h
e s i z i n g X O R
f u n c t i o n
•
W e w
i l l u
s e
2 - i n p u
t N O T
, A N D a n
d O
R
g a
t e s
t o
s y n
t h e s i z
e t h i s f u n c
t i o n
•
W e
l o o k
f o r w a y s o
f a s s e r t i n g a
T R U E
c o n
d i t i o n
( l o g
i c a l
‘ 1 ’ ) o u
t p u t
i n t h e
t r u t h
t a b l e
•
W e
t h e n
l o g
i c a
l l y c o m
b i n e t
h e s e
c o n
d i t i o n
s
8/6/2019 Introduction to Digital Logic 1
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U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
X O R
S y n t h e s i s c o
n t i n u e
d
0
1
1
1
0
1
1
1
0
0
0
0
( p X O R
q )
q
p x = ( N O T p ) A N D q
O U T P U T
= x O R y
y = p A N D ( N O T q )
8/6/2019 Introduction to Digital Logic 1
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U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
C o m p
l e t e d X O R S y n t h e s
i s
U 2 S N 7 4 0 8
U 5 S N 7 4 3 2 O U T P U
p q
U 4 S N 7 4 0 8
U 1 S N 7 4 0 4
U 3 S N 7 4 0 4
x = ( N O T p ) A N D
q
y = p A N D ( N
O T q )
O U T P U T =
x O R
y
8/6/2019 Introduction to Digital Logic 1
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8/6/2019 Introduction to Digital Logic 1
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U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
C o m p a r i n g C
l o c k F
r e q u e n
c y
a n d C y c l e T i m e
1
/ 1 0 0 0 , 0
0 0 , 0 0 0 s e c
1 n s
1 0 9 c p s
1
G H z
1
/ 1 0 0 0 , 0
0 0 s e
c
1 u s
1 0 6 c p s
1
M H z
1
/ 1 , 0
0 0 s e c
1 m s
1 0 3 c p s
1
k H z
1
s e c
1 s
1 c p s
1
H z
C y c l e L
e n g t h
F
r e q u e n c y
8/6/2019 Introduction to Digital Logic 1
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U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
i
l l u s t r a t i n g P r
o p a g a t i o n D e
l a y
U 1 S N 7 4 0 0
U 2 S N 7 4 0 0
U
3 S N 7 4 0 0
U 4 S
N 7 4 0 0
H L
S W 1
D O U T
+
D I N
T
T i m
e
( s )
0 .
0
0
5
0
. 0
0
n
1
0
0
. 0
0
n
1
5
0
. 0
0
n
2
0
0
. 0
0
n
D I N
0
. 0
0
5
. 0
0
D O U T
0
. 0
0
4
. 0
0
S I G N A L I N G D E L A Y
8/6/2019 Introduction to Digital Logic 1
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U M B C / C M S C 3 1 3
/ D a v
i d B o u r n e r
< b o u
r n e r @ u m
b c . e
d u
>
P
o w e r D i s s i p a
t i o n
•
W h e n I C g a t e s a r e s w i
t c h i n g , t h e y
t r a n s f e r c h a r g e
f r o m
• E i t h e
r t h e D C p o w e r s u p p l y t o t h e “ l o a d ” i . e .
g a t e s
a t t a c h e d t o
t h e i r o u t p u
t t e r m i n a l …
.
• … . o r
f r o m t h e l o a d t o t h e g r o
u n d r e t u r n
•
A n y m o t i o n o f c h a r g e
i n a c i r c u i t i s a c u r r e n t
( m e a s u r e d
i n u n i t s o f A m p e r e s )
•
A n y c u r r e n
t I i n a c i r c u
i t u n d e r a p
o t e n t i a l d i f f e r e n c e
V ( v o l t s ) i s p o w e r d i s s
i p a t e d - P =
I x V W a t t s . T h i s
p r o d u c e s h e a t .
•
H e a t m u s t
b e m o v e d o
f f t h e c h i p t o k e e p t h e I C ’ s
t e m p e r a t u r e w i t h i n s a f e o p e r a t i n g
l i m i t s .
8/6/2019 Introduction to Digital Logic 1
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L e t ’ s C h e c k o f f O b j e c t i v e s
1 . R e v i e w e d 3 d i g
i t a l l o g i c c l a s s i f i c a t i o n s
2 . M o
d e l e d s i m p l e g a t e f u n c t i o n s
3 . D e f i n e d t h e t e r m t r u t h t a b l e
4 . W r o t e t r u t h t a b
l e s f o r N O T , O R , A N D
5 . M a p p e d l o g i c g
a t e c i r c u i t t o E X O R
6 . R e v i e w e d c a s c
a d e d O R , A N D l o g i c
7 . I d e
n t i f i e d t h e T
W O P ’ s - c r i t i c a l i s s u e s
t h a t i m p a c t c o m
p u t e r s a t t h
e g a t e l e v e l
1 . P r o p a g
a t i o n D e l a y
2 . P o w e r D i s s i p a t i o n
U M B C / C M S C 3 1 3 /
D a v
i d B o u r n e r
< b o u r n e r @ u m
b c . e
d u
>