Elenco Electronics MO-1251 Manual do Utilizador descarregar pdf (Página 60)

66

2

6

CLK

CLK

ENABLE

15

RESET

14

LAMP

TEST

3

{

a 10

b

12

13

e

g

9

11

6

CARRY OUT 5

RIPPLE RIPPLE

BLANKING

IN

BLANKING OUT

18

a

fi

l_alb

d

LED SEGMENT

DESIGNATIONS

FIG. 11-PINOUT

DIAGRAM OF

THE

4033B

decade

counter

with 7- segment

display

driver

having

RIPPLE BLANKING

facility

(a),

and

LED

-segment

designations

(b).

blanked,

although

the counter

IC con-

tinues to count.

The

IC also has

an

UNGATEDCSEGMENTOUTPUT

pin,

which

can

be used

in conjunction

with

exter-

nal logic

to control

the display

seg-

ments

individually.

Figure 11 shows

the pinout

diagram

of the

4033B. That

IC features

RIPPLE

BLANKING

Input and

output pin,

which

can be used

to blank

the

leading and

trailing zeros

in multi-

decade applica-

tions.

The "O"

display blanks

auto-

matically

when the RIPPLE

BLANKING

INPUT pm

is held low.

Additionally,

the IC

features a LAMP

TEST pin;

that if

pulled

high,

will

drive

all display

de-

coded

outputs

high,

illuminating

all

CLOCK

INPUT

3

HUNDREDS

DISPLAY

CLK

ICI

CARRY

40336

RBI

RBO

15

11©111

+v

î

CLK 1

INPUT

101

121

131 91

111

61

71

a

b

cd

e

f g

DECODED

OUTPUTS

TO 7-

SEGMENT

DISPLAY

DISPLAY

ENABLE IN

CLK

ICI

40266

RESET

CLK ENABLE

CARRY

OUT

115

18

12

+

}V

J

TO CLK

5 INPUT OF

NEXT

DECADE

COUNTER

FIG.

12 -THE

4026B CONNECTED

for de-

cade

dividing

and

7- segment

display op-

eration;

DISPLAY

ENABLE

input

must

be tied

high

for display

illumina-

tion.

V

12

CLK 1

INPUT

101

121

131

91 nl

61 71

a

b

c de f

g

DECODED

OUTPUTS

TO 7- SEGMENT

DISPLAY

RBI

ICI

4033B

CLK

LAMP

RESET

TEST CLK

ENABLE

CARRY

OUT

115

!14

12 18

+V

16

TO CLK

5

INPUT

OF

NEXT

DECADE

COUNTER

FIG.

13-THE

4033B

CONNECTED

for de-

cade

dividing and

7- segment

display op-

eration;

RBI (ripple

blanking

input) must be

tied high for

normal display operation,

or

low for zero -digit

suppression.

7- segments

of the display.

Figures

12 and 13 show

how to con-

nect the

4026B and

4033B,

for de-

cade

7- segment

display

operation.

For each

positive edge

of the

clock,

the counter

will illuminate the proper

LED

segments

to display

the decimal

numbers

from 0 to

9.

When

using

the

4026B,

the DISPLAY

ENABLE INPUT

pin

must

be tied

high if the display

is to

be

illuminated.

When using the

4033B,

the

RBI INPUT

(ripple- blanking

input)

must be tied

high

if the display

is to

operate

normally,

or tied low to

give

zero-digit

suppression.

Notice

that

in

both circuits

if multi- decade

counting

TENS

DISPLAY

HIM

CLK

RBI

IC2

CARRY

4033B

OUT

15

141

UNITS

DISPLAY

CLK

CARRY

1C3

OUT

40338

RBI

15

14

Nu

is used,

the CARRY

OUT of one

stage

becomes

the clock

input to the

next

stage.

Figure 14 shows

how to

intercon-

nect

several 4033B's

for multi- decade

counting;

additionally,

to

give auto-

matic

suppression

of leading

and

trailing

zeros so that,

for example, the

count

009.90

will actually

be dis-

played as 9.9.

To get

leading zero

suppression

on the

integer

side, the

RBI INPUT of the

Most Significant

Bit'

(MSB) IC

must be tied

low; its

RBO

(ripple

blanking output)

must be con-

nected to the

RBI of the

next MSB

IC,

and

so on down

the

line. To get trail-

ing zero

suppression on

the fraction

side

of

the

display, the

RBI pin

of the

r

CLKA

ea' ENABLE A

i2

T

e

i

7

T

9.CLKB

iUs

ENABLE B

,T,

i 15 ;RESET B

L

4518B OR 4520B

RESET

A

CLK

4 -STAGE

COUNTER

RESET

04A,61

.-r,

4 -STAGE

COUNTER

RESET

Q1B

Q2B

11

t

'12'1

Q3B'131

Q4B-S

14`'

7

8

4----

í

FIG. 15-PINOUT DIAGRAM

OF

THE 4518B

dual decade -counter, and

4520B

dual bin-

ary- counter.

TENTHS

DISPLAY

CLK

RBO

CARRY

IC4

OUT

4033B

RBI

15

W©

FIG.

14-THE

4033B CONNECTED

so

that RBI and

RBO give

leading

and

trailing

zero

suppression

in a multi- decade

display.

HUNDREDTHS

DISPLAY

MUM

CLK

RBO

CARRY

IC5

OUT

40338

RBI

15

14

so

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