Heathkit H9 User Manual

n$ffiuAt

for the

VIDEO

Model

oPERATION

TERMINAL

H9

595-2017-03

,l

I

HEATH

COMPANY

.

BENTON HARBOR,

MICHIGAN

HEATH

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Heathkit@

for the

Manual

VIDEO

Model

oPERATION

TERMINAL

H9

595-2017-03

HEATH COMPANY

tsENTON

HARBOR,

MICHIGAN 49022

Copyrlght

Ail Rights Reserved

Printed in tho United

1977

@

Heath Company

Stat€8 of

Amorica

Pase2

@

INTRODUCTION.

OPERATION
Local Function Keys
Special
Control Characters

HoId Screen .. . .

SYSTEM

READIUSTMENT
Brightness
Focus
Centering
Height
width
Repeat Rate
Cleaning

Function Keys.

CONSIDERATIONS
Heathkit
Standards
General

Computer System Interface

Interfacing

.

TABLE

OF CONTENTS

CIRCUIT DESCRIPTION

BasicOverview.. ....47

PowerSupply .......48

4

5
8
B

10
L2

26
26
26
27
28
30
30

Video
CharacterGenerator
KeyboardCircuitBoard
RAM
Timing and Processing
Input/Output

SEMICONDUCTOR IDENTIFICATION

ComponentNumberlndex
PartNumberlndex
ROM

X-RAY Views ...

Circuits

and Counter ...

(I/O)

and PLA Programs

(TPU)

Unit

..

(Illustration

.......

.....,..50

....54

.. . . .. 57

........68

....... 85

Booklet, Page

48

55

... 66

...71

74-23)

SPECIFICATIONS
TROUBLESHOOTING

Troubleshooting
Troubleshooting
Shipping Information

Charts.
Waveforms .

.. . .

32
33

35
43
46

SCHEMATIC....

WARRANTY....

CUSTOMER

SERVICE

Fold-in

.. Insidefrontcover

.... Insiderear

cover

INTRODUCTION

The Heathkit Model
information coming from a digital computer
formation typed in from the

is

tion
(CRT)

one time

displayed orta

that is capable of displaying 960 characters at

(12

rows with 80

A 67-key ASCII keyboard,
pose

and

edit directly on

64

different characters and
This message or
the standard
current
parallel

The Video Terminal
computer
plication,
communicate
language
using toggle switches.

serial
loop)
I/O interface to a

in

a dedicated format, in a stand-alone ap-

or in a time-sharing system. It lets

(Basic,

H9 Video Terminal

(diagonal)

L2"

which

the

program

to a digital

with

Assembler,

can be transmitted through

I/O interface

paper

can be used with any digital

a digital computer

The Video Terminal

can display

keyboard. This informa-

cathode

characters

permits you

has

CRT,

zq

different functions.

(EIA,

computer or through the

tape reader/punch.

rather

etc,)

ray

per

row).

a capability of

TTL,

or

in higher-level

than

in-

or

tube

to com-

20

mA

you
just

is

also

much
electro-mechanical teletypewriter systems. You
select any data

Other important features

These features,
cabinet,
peripheral

faster

.
.
.
o
o

o
.
o
o

(up

to

9600

rate between

Automatic
Cursor controls
Erase to
Erase
Short form
characters)
Automatic
Plot mode
Built-in
Transmit page

make

for

scrolling

end of

page

(four

line carryover

speaker

along with

the Video Terminal

your

computer

baud) than

110 and

include:

line

12-line

(audible

the

system.

the standard

g0OO

baud.

columns of

bell)

attractively-styled

a versatile

can

zO

Pase4

OPERATION

The
ASCII
(upper

symbols.
twenty-four
Pictorial
location

raphs.

Video

coded

case

Thirty-two

1-1

of the

Terminal

characters.

only),
special

(Illustration

keys

will

numbers,

standard

functions

described

generate

They

include

punctuation,

control
can also

Booklet,

in

the following

and

the

characters

be

page

1)

display

and

generated.

shows

64

alphabet

many

and

the

parag-

@

The

local

ters;

they

CURSOR

These
they

keys

are labeled

uP

cuRSoR (f)

lrri

DO\

RIGHT
LEFT

CURSOR

function

only

CONTROL

are

CURSOR

CURSOR

keys

affect

on

the far

with

(+)

(---,)

(<-)

the

arrows.

do not

display.

KEYS

right

I

|

LOCAL

transmit

of the

These
the

cursor
character
or one
line

as indicated

by

the

ASCII

charac-

keyboard

keys

move

one

position

character

arrow.

FUNCTION

HOME
This

key moves

tion

on the

and

ERASE

This

key

tion to
ERASE
This

spaces. It

the

key

EOL

PAGE
erases

KEYS

first

(End

erases

end

all text

places

also

the

cursor

line.

Of Line)

the

text

of that

the

from

line.

and

cursor

to

fills

the

first

the

current

page (screen)

the

in

the home

character

cursor

position.

loca-

loca-

with

@

-

Page5

AUTO CARRY

pushed

this key

When

goes

to the

is typed.

text

cursor will

fhome

scroll mode
"Hold

SHORT FORM
When this key is

changed from twelve lines
leased) to four
twelve lines of 20
writing
are

position),

Screen"

programs

short.

is

beginning of

At the end of

start over at the beginning of the first line

providing

(SCROLL

on

columns - each column

characters. Short

in

in, the cursor

the next

key released). Also, refer to

Page 8.

pushed in,

machine language

automatically

full

line

the bottom

the Terminal is not in

the display format is

of 80 characters

a

after

line of

consisting of

form is

where

text, the

fkey

useful for

entries

SPECIAL

SCROtt

When this key

line of

re-

lines

of text
upwardJ and
moves up

bottom line. In

the
characters
lost. The remaining three columns move to the
one column
right

column.
the non-scroll
lines

of
flashes at the start
entries will write over the existing text on the
line. Also, refer

FUNCTION

pushed

is

are typed, the first line is

lost. Each remaining
line

one

lines

[12

position,

When

position),

text are typed, the cursor

to

in, and after the first twelve

position

short

of

the SCROLL key

of

"Hold Screen"

and the cursor moves to

form,

20

characters)

and the cursor moves to the

and after the

page position. Further

the

left

on

KEYS

erased

returns

(scrolled

character
column of

is

erased

is released

first

twelve

to and

Page

8,

line

24o

and

left

(in

typed

first

RETURN

This

tion
Return ASCII code
into a RAM
space. That is, a carriage
other
ter,

except

LINE FEED

This key moves
transmits
feed does not write
able

RUB OUT

This key transmits
out
displayable

(Carriage

key moves the cursor

the line it is

of

location only

character.

in

the

the line

character, except

does not

character,

Return)

currently

(control

Return is

plot

mode.

the cursor down

feed ASCII code

into RAM and

in the

an ASCII rub out code

write into RAM and

to the first character

in and it transmits the

Return

M).

if

that

return

will not write over any

a non-displayable charac-

plot

except in the

can be written

location

it is not a display-

mode.

contains

line

one
(control

(delete).

is

it

plot

mode.

posi-

and

Line

)).

Rub

a non-

(Escape)

ESC
This

key

transmits

not

write intoRAM

ter,

except in

a

REPT

When this

it

will repeat the function
as long as both keys are held down. The
repeat rates
second. If the baud rate that has been selected
than the
the slower rate.

(Repeat)

key is held in, along with another key,

repeat rate,

the

are

an ASCII

and

plot

3.7-,

the

escape

it is

a non-displayablecharac-

mode.

the

of

7.5-,

L5-, or

repeat function will

other

code.

Escape does

key at a

30-characters

preset

presettable

is less

operate

it

rate

per

at

PLOT

pushed

When this
for

the

key is

first line

displayed on

the

of

each of the four bottom

the text is blanked except

in,

page.

This first line, however, is

lines

of the
screen. The screen area above the bottom four lines is
divided into 128 scan
one character

wide,
characters displayed
position
proportional

code

P,

or
and
directly
tion
ASCII
all ASCII L's

of the dash above

to the binary value of the

for

that character. For

ASCII

null, is all zeros,

it

appears

above the

Booklet, Page 2) gives

code for each key

has a binary value
appears at the top line
the rub

In

out character.

plot

the

mode,

lines.

will appear above each of the

in the bottom four lines. The

the bottom

at

ASCII

entry.

(line

all characters are

but their special cursor

plemented.
written
control

into
character that appears

Even though
cannot be

generated from the keyboard,

is, a RETURN

That

but the cursor does not move. Any

RAM,

lower-case alphabetic

the

Pictorial r-2. A

See

the bottom line

(line

z-bit ASCII

example, a CTRL/SHIFT

its binary value

so

is

of the 128 line

null. Pictorial r-g

line

the

number and the

A RUB

of

OUT

727,

128) in the

written

movements

(carriage

fllustra-

(delete)

so the dash

space above

into

not im-

are

return) is

in the text will flash.

characters

they can be

dash,

0) is

zero,

space

or

RAM,

entered into RAM
other

characters,
characters
on the appropriate
case
characters
through

BAUD

is

characters

represented

o17 71,'17.

RATE

When this key is
operate at

110 baud. When this key is

from

the digital

the binary value

stored in RAM

line

in

stored in

by

released

computer, Like

of the lower

and

the dash is

the 128-line

RAM

are

displayed

the ASCII

(out),

the

space. Lower

words

Terminal will

pushed

rate is set by the BAUD RATE switch on

panel.

preset

or the

jumper

The rear

wire on

panel

switch selects either

preset

The

baud.

the I/O circuit board.

baud

is

determined

OFF LINE
When

this
from transmitting
I/O,

but it

tion through

read

or

Terminal

tape

is

pushed

key

is

in,

the

or receiving data from

does not interrupt

parallel

the

the

on

line from

off

paper

port.

I/O

tape reader/punch

the digital computer.

Terminal is inhibited

transmission

This lets

you punch

all

case

d.isplayed

as the

010 0000

in, the

the rear

300 baud

by a

the serial

recep-

or

the

while

L I NE

(B

INARY

VALUE I27)

(B
VALUE O)

LIN

INARY

NON-

r^rc

',iil,

3iililfijfi

PICTORIAL \-2

@

%

Page 7

BREAK
When this

space
the

computer

not

confuse
fined
positive

pressed

be

page

mit

FULL
When this key is

in

the half

keyboard

RAM

out the
DUPLEX
the full
from
back to
displayed

XMIT

key is

at the

serial

that

this

as

zero

current in

voltage,

any time

function.

DUPLEX

duplex mode.

parallel

or

and, at

the keyboard

the same time,

serial and

key is

duplex

the Terminal

on the

PAGE

(Transmit

pushed

you

space with

or a TTL logic

released

pushed

mode. Data

screen.

in,

output,

wish

a 20 mA

you

want

(out),

input

parallel

in,

is

sent to the

before it

It is

Page)

generates

it

generally

to interrupt

an ASCII

0. The BREAK

to terminate

the Terminal

That is,

is written

ASCII

outputs.

the Terminal

from

computer and

is written into

space. It

current

data from

characters are

When the FULL
parallel

the

a

continuous

used

to tell

execution.

is de-

loop,

an

EIA

key

can

the trans-

operates

directly into

sent

operates in

input

echoed

RAM

and

Do

the

or

data is
lel
of the

transmit page

CTRL
When

other keys,
keys.
(carriage
shown

SHIFT
When

key,
key will
generate
necessary
alphabetic
cally

CTRL/SHIFT

transmitted

and serial ports

ports.

two

(Control)

this key is

it

For instance,

return).

in Pictorial

this

key is

the

character

be

displayed.

lower-case

push

to

characters

in the

keyboard

simultaneously

at a rate

Press

the BREAK

function.

used

in

changes

those

CTRL M is

The

control key

1-3.

used in

printed

Since

alphabetic

the

shift key

-

encoder.

outboth

determined

key to

conjunction

keys

to special

equivalent

combinations

conjunction

on the upper

the Terminal

characters,

generate

to

they

are shifted

the

by

the

interrupt

with

some

function

to

a return

with another

portion

does

it is

upper-case

automati-

paral-

slower

the

of

the

are

ofthat

not
not

you

When
mitted from
rent

cursor location

page.

When

returns

home

momentarily press

the RAM

it has

and the transmit page

(screen),

proceeding

and
completed

this key,

starting from

the

data

to the

page,

mode

is

trans-

the cur-

end of the

the

cursor

stops. The

These

two keys
keys
instance,
CTRL,

puts

provide

to

the

an ASCII

are

used in

additional

CTRL/SHIFT

SHIFT,

null

and

fall

conjunction

special function

(which

P

the P

zeros)

means, press

keys at

on the bus.

with

the

same time)

other

keys. For

the

t"n"t

@

The Terminal
ters from the keyboard.
not write into RAM,
screen. Exceptions

plot

the
the control
keyboard
The

four characters

Line Feed
plicates

Carriage Return
ter duplicates

generates

nor are they

are

mode. The

characters. It will recognize

or from the

Terminal recognizes

are:

(LF

or CTRL

the LINE FEED key.

(CR

the RETURN

CONTROT

all 32 ASCII

Normally these

outlined in the description

parallel

])

or CTRL M) - This

control

characters do

displayed

only

these from

or serial input

-

This

character du-

key.

charac-

on
four

ports.

charac-

HOLD

CHARACTERS

Back

Space

moves the cursor to the left

the

of
of

the

tion without disturbing the
played.

(Bel

Bell
Terminal to
an internal speaker. Pictorial 1-3
trol and normal characters thattheTerminal
generate.

SCREEN

(BS

or CTRL H) - This

one character

character being dis-

or

G) - This

CTRL

sound a short audible tone

character causes the

character

posi-

through

shows the con-

can

If the screen has been
should occur,

pushed

not
mode. The
and blinks. All external
occurs. Data can only be
nal by the keyboard. The Terminal stays
screen mode until the SCROLL
until the ERASE

but can't

in, the Terminal

cursor

filled,

returns to the start of

inputs are

PAGE key is

and a scroll

because the SCROLL key

goes

into the hold

disabled when this

transmitted

out of

key is

pressed.

page

pushed

function

screen

location

the Termi-

in

the hold

in

You

can use this feature

is

tape reader/punch
reader/punch
to fill

up the
been written,
handshake
stops

the tape

or

contents
press
screen full

the

can read

screen

the

signal

from running.

of the

screen.

ERASE

program

of

in

conjunction

for reviewing program

the tape

quickly,

hold

coming

When

PAGE

information

at its maximum

then

screen mode

from

You

you

key

and receive

with the

after the last line

disables
the Terminal.
can

then

are finished,

automatically.

paper

tapes.

speed

review

another

The

has

the

This

the

just

SYSTEM

CONSIDERATIONS

Video

digital

section

Terminal

Refer

System.

computer

"General

the

interface

following

The
Interface Standards"
Heathkit H9
tal

Computer.

Heathkit Computer

Heathkit
minal,
select

refer to

the suitable

"Heathkit

explains

to this

with

Computer

how to

Heathkit

the

to

you

you

your

if

are

H9

section

If

Interfacing"

scheme'

System

interface

HB Digi-

have the

a non-

using

Video

section

the

Ter-

and

Paselo

@

HEATHKIT

The

following
signated
Standard.

H9 Video
Both
must be
format:

as the

Use these

Terminal

the Video

wired

Data
Signal Level
Word
Parity

COMPUTER

interface

Heathkit

standards

with

Terminal

to operate

Rate

Length

configuration
Computer

the
and

in the following

System Interface

you

when

H8 Digital

the Digital

600 Baud
EIA
8 Bits
None

600 BAUD

SYSTEM

has

been

interface

Computer.

Computer

standard

RS-232C

or

de-

the

INTERFACE

To

do this:

1.. Examine
Video Terminal
shown in Pictorial 2-1.

2.

Examine
HB Digital

as shown in Pictorial 2-2.

3.

Examine the interconnecting
tween the H9
wired

as shown in Pictorial 2-3

Booklet, Page 3).

READER
CONTROL
DISABLE

STANDARDS

I/O

the

the Serial I/O

Computer to make

circuit board in

to make sure it

circuit board in the

and the HB) to make

il{stT

--

-f',ffi;

-

sure

-\J

--nA

the H9

is

wired

it is

wired

cable

sure

(Illustration

27 0a

/

t

as

(be­it

is

r/o

I

"j't.*-H

-6

P60l

P601-7

-8

P60l

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P60l

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P60l
P60l-lt
P60t-12

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PICTORIAL

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o

o
o

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o
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o

o
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o

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NOTE:

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the

preset

select appears

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lug 3 to lug 2. Be

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The number of bits
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WORD LENGTH N2

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6

7
8

N2)

word is determined by

37

programmed

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and

for

(pin

38)

5-,

N1

0

o

1.
1

6-,

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0
1,
0

1

the N1

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or

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The UART

erate a

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parity

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received

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follow the last data

generate a parity

the UART

The Terminal
Pictorial 2-16

to

was

(Illustration

can

the

The stop bit

bit. A logic 0 on

initially wired for no

programmed

be

output or to eliminate

the P input

parity

bit from the transmitted

(s)

will immediately

the P input causes

bit.

Booklet, Page

curs when a wire is connected between

your

bit,

parity

bit is

own special applica-

connect

a wire between

on the I/O circuit board. The
the H9 system. However, if

requires the

tion
holesPand

parity

*.

to either

(pin

parity.

5).

gen-

35) to the

See

This oc-

holes P and +

not used

with

Pase22

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This input

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that
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A logic o on
immediately after

inserts even

the

Since

is not connected.

input

requires a

odd or

select

KEYBOARD

jumper

A
keyboard circuit
repeat

This is the

ond.

screen when

the
key are
"Repeat
section of
repeat rate.

PARITY

(E)

to

checked

by the

parity

if

E input

the

parity immediately

Terminal does

parity bit,

even

PROGRAMMING

wire connection

rates; 3.7-,

rate at which characters

held down at the same time.

Rate"

this Manual

(E)

the UART

was selected

the data

parity,

board

7.5-,

the REPT

instructions in the

selects

receiver and

as explained

(pin

36) will insert odd
A logic

bits.

after the data

not use the

your

If

Pictorial

lets

\5-, or

(repeat)

if

special

2-77

on the bottom

you

30-characters

you

want to change

select one of

key and a character

the type

generated

1

parity

shows

are written on

"Readjustment"

parity

of

by the
above.

parity

input

this

on

bit, the

application

how to

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Refer to the

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o

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TYPICAL

Parallel

following

The

the signal

panel.

rear

the

PIN

#

7

2

3

4

5
6
7
8

I

TERMINAL/COMPUTER

Input/Output

Connections

parallel I/O connector

ofthe

parallel

Parallel

Output

Take Data o

pin

each

on

DATA DESCRIPTION

Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6

T

BiI
Bit 8

DAVo

SYSTEMS

describes

chart

I/O connector

o
o

o
o

r
.

.

on

Positive true logic.
High

Level Output Voltage

(High

pA
LowLevel

(Low

Level

Output Current).

OutputVoltage

Level

Output Current).

Standard 74L5175

Available

data

Data

will hold

available

at

Output
Terminal
is
device.
HighLevel

(High

p.A

Low
(Low

Refer to the

OutputVoltage[Vr")

Level Output

Level Output

Level Output

"Handshake

PICTORIAL

latches.

- Normally

this line

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the

CurrentJ.

Voltage

Current).

(Vo")

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low to

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Timing"

2.I7

:

2.7 min.

0.4 Vmax.

The

high.

indicate

that there

for the external

2.7Y min.
V max.

0.4
section.

@

@

Video

@
@

-400

amA

-400

a mA

10

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Pagezs

PIN

#

17
72
13
74
15
16
77
18

19 mAv; Data Taken

20 DAV;

DATA DESCRIPTION

B

t1

B

t2

B

t3

B

t4

B

t5

B

t6

B

t7

B

t8

Parallel

Input

Data

Sent

o

Positive true logic.

o

High Level Input Voltage

o

Low Level Input Voltage

.
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.
o

o

o
.
.

.

Level Input

Low
o.4

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Current

Standard 74L5244 input

Reset

Output Data Available - Normally high.

The external device will

to indicate
received

the data.

send new

data until n-Dffz, has returned high.

to the

Terminal

The

High Level Input Voltage
Low Level Input Voltage
Low Level Input
Refer to

the

Current

"Handshake

Input Data Available - Normall5r

external device will
indicate

that there

inputted to the

o

High Level Input

o

Low Level Input Voltage

o

Low

Level

Input

o

Refer

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is

parallel

Voltage

Current

(Vr")
(Vrr)
(Irr)

buffer.

pull

that it has

Terminal will not

(Vnt)
(Vrr)
(Irr)

Timing"

pull

this line

data ready to be

input.

(Vrrr)
[Vrr,)

(Irr)

Timing"

:

2

V min.

:

0.8 V max.

:

-2OO

p"A

this line low

:

2 V min.

:

V max.

0.8

:

2.8 mA

max.

section.

high. The

low to

:

2 V min.

:

0.8 V max.

:

1.8

mA max.

section.

max.

@

27

22
23
24

m-AV,

Ground

Data Received

.

o

.

.

Input

Reset
Terminal sends a negative-going
wide)
that the Terminal has received and is finished with
the data.
High Level

@

Low Level

@

Refer

this line to indicate to the external device

on

-+oo pA

(Ior).

4 mA

to the "Handshake Timing"

Available - Normally high. The

Data

pluse

:

Output

(Ior).

Output

Voltage

Voltage

(Vo")

(Vor)

2.7 V min.

:

0.4 V max.

section.

(:

25 p,S

Parallel

Handshake

Timing

Pictorial

2-18
handshake
port.

DAV0

I NAL

TERM

RDAVO

TXTTRNAL

DAVI

EXTERNAL

RDAVI

IERMINAL

shows

signals

the timing

associated

LOW LTVEL

RDAV-o RESEIS

LOW

waveforms

with

the

SAYS

"DATA

LOW LEVFL

DATS

LFVEL

SAYS

of the

parallel

SAY S

I/O

Handshake Timing

READY FOR

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HAVE DAIA

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Connections

serial I/O

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PIN

#

7

2

3

4

5 Reader

6 Reader

connector

of the

TTY
AND

Serial Out
Serial Out
Serial
Serial

Baud Rate

serial I/O

(ACTIVE

PASSIVEI

[+)
(-)

(+)

In
In

[-)

(+)

Start

(-)

Start

Out

chart describes

connector

SERIAL

the

on the

PORT NOMENCLATURE

EIA RS-232C

Serial

Serial In

Baud Rate

Out

Out

TTL

Serial Out
Serial In

Baud Rate

Out

B
9 Ground

Ground Ground

@

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Typical

Pictorial
Computer
Video

Pictorial
tween

System

2-L9

System Interface

Terminal

2-20

the

Video

reader/punch.

shows the

and

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shows

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Terminal

typical

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Standard)

computer.

I/O connections

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H9

VIDEO

TERMINAL

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paper

Typical

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Computer

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READIUSTMENT

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to suit

your

periods

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with

characters.

adjustments

maintain

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separately without

your

when

eyes

of time. Whenever

video

the

This section

need to

may
Terminal. Each of

ness and
affecting other

BRIGHTNESS
Adjust the display brightness

A dim display
the screen
you

change the

readjust
The BRIGHTNESS control

board) is shown
To adjust the brightness:

1.. Remove the cabinet shell and set it aside.

2. Fill the

3. Adjust the BRIGHTNESS control to

4. Reinstall the

contains

make to

Focus) can be adjusted

adjustments.

is

for

extended

focus.

the

desirable character brightness.

several

properly

the adjustments

easier on

brightness, it is also a

in Pictorial 3-1.

screen

cabinet shell.

that

your

for Bright-

needs.

own

you

look at

good

idea to

circuit

obtain

you

Video

To adjust the focus:

1. Remove the cabinet shell and set it aside.

2. Fill

3. Adjust the FOCUS

4. Reinstall

CENTERING

The display

should have the
it does

the top
To

adjust the

1. Remove

2. Fill

NOTE: Use an

a

careful

or

adjustments.

the screen with characters.

focus. Look

and

corners of the screen as

adjustment.

should be centered

same amount of space on the right

on the left, and the

it

as

does

on the bottom.

centering:

the cabinet

the

screen with

you

do not touch

the anode lead

the

at

the cabinet shell.

same amount

insulated screwdriver

when

control to obtain the best

characters at the

you

on the screen. It

shell and
characters.

the video circuit board

you

make the following

set it

edges

make this

as

of space on

aside.

and be

FOCUS

focus adjustment,

The
whenever
tinct characters

The
shown

the brightness

Pictorial

in

control

FOCUS

which should be made

is readjusted, assures dis-

on the screen.

(on

the

3-1.

video circuit

board) is

3. Refer

4.

to Pictorial
ing magnets,
center the
the

centering
cal and horizontal
use the minimum
(magnet

that is necessary.
to

and

Reinstall

tabs

compromise

perfect

the

3-1

first

display

magnets

linearity

spread as far apart

Sometimes

between

linearity.

cabinet shell.

rotate

and

one, then the

on the screen. Because

will affect the verti-

amount

perfect

the center-

other, to

of the

display,

of correction

possible)

as

you

will have
centering

@

,'ilIli^ll,'\

t0cus

BRtGilTlttss

_

t"n"tt

\\

\\

\

HEIGHT
The

exact

ever,

the
apparent
sharper,

The

HEIGHT

shown

in

height

dots

that

on a large

more

distinct

control

Pictorial

,6-

of the

form

display.

characters.

(on

3-1.

display
the

characters

A

small

the

video

is not

critical.

become

display provides

circuit board)

e

€e

e

-@

PICTORIAL

To

How-

more

is

3.1

adjust

1..

2.

3.

4.

the height

Remove
Fill

the

Turn

the
while you
trol

at

the
appealing
play,

make

appear

Reinstall

on the

of the

the

cabinet

screen

HEIGHT

watch

position

display.

sure

the

cabinet

display:

shell

with

characters.

control

the

display.

that provides

If you

all

twelve

screen.

shell.

and

set it

through

Leave

prefer

character

a

large

I

lt

aside.

its

the

the

range

con_

most

dis_

lines

Pase28

WIDTH

@

A width
select one of three display widths;
extra wide. Pictorial

nection for

display should normally
right
normal

wide

only

WARNING: There
video
width

jumper

and left

setting will

and extra wide settings are usually required

in low

circuit

jumper

wire on the

3-2 shows the

each of these settings. The

sides of the screen. In most

provide

line voltage areas.

is high voltage

board. DO NOT attempt to change the

when the

video

circuit board can

normal, wide, and

iumper

be about L12' - 7'from

adequate

present

power

is

turned on.

wire con-

width of the

the

cases, the

width.

The

on the

To

change the

7. Turn the

2. Remove

3. Remove the video

4.

5.

6, Reinstall the

7. Reinstall

display width:

chassis.

Pull the

pin.
Insert

the

pin

that corresponds to

sire.

ON/OFF switch to OFF.

the cabinet shell and set it

circuit board from the

jumper

the cabinet shell.

wire

jumper

wire into the

circuit board

out of the connector

connector

width

the

in

the chassis.

aside.

you

de-

Page

29

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REPEAT

When
held
peatedly
set at 3.7,
rial 3-3 shows the
bottom of the keyboard circuit board) for each of the
repeat
to determine which one best suits

To

change the

RATE

the REPT

down

written

rates.

Turn

7.

2. Remove

(repeat)

at the same time, the character is re-

on

7.5,

\5, or

You may want

repeat rate:

the ON/OFF switch OFF.

key and any character

the

30

fumper

bottom

the

screen.

characters

The repeat rate can be

wire connection

try

to

all of the

panel

per

second.

your

and set

key are

Picto-

(on

the

repeat rates

needs.

it

aside.

Pull

3.
pin.

4, Insert the

pin
desire.
Reinstall the bottom

5.
CLEANING
You

cloth to clean
the dust
smudges still remain,
with a mild soap and a soft cloth. Be careful
not scratch the

can

use

from

jumper

the

that corresponds to the repeat rate

mild household detergent and a soft

any

the cabinet

the

plastic

jumper

of

window

clean

window.

wire out of

wire into the connector

panel.

the Video Terminal. Wipe

with

the window

the

a soft

connector

cloth.

carefully

you

you

If

do

{ } F-----t

b iltb I

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p

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N/

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Page

31

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E

PICTORIAL

3.3

SPECIFICATIONS

..

CRT

Display

Keyboard

Interfaces

BAUD Rates .

Characters

Format 960

phosphor.

72" diagonal,

panel

filter.

characters.

characters.

67 keys including: 52-key

5 cursor control
10

(full

Serial

EIA/RS-z32C

(20

TTY
TTL
Reader

Parallel

8-bit input

8-bit
4 handshakes

Seven, user selectable - 11"0, 300, 600, L200, 2400,

4800, and

x

7 dot matrix. ASCII

5

bers, and

P4

Normal

form

Short

special

(TTL

output

function/mode keys

or half duplex):

mA current loop)

Control

9600.

punctuation.

(20

loads):

keys

mA current loop)

Glare-free

-

mode

- 48 lines of

ASCII

upper case alphabet, num-

neutral

lines of 8O

tZ

20 characters.

keyboard

front

OperatingTemperature.,..

Power

Voltage Requirements . .

Dimensions

Weight

Requirements . . . . 120 VAC,

. L20 VAC

The Heath
instruments
without incurring

feautres in

0oto40oC.

24O VAC,5O16O H2,50

240 VAC

15-518'W

(39.7 x

32

Company leserves

and to change

any

instruments

specifications at any time

obligation

previously

(100
(2oo

52.7 x 31.8 cm.)

(1+,5

lbs.

the rightto

to incorporate

sold.

Hz,

50/60

-

- 27o VAC),50/60 Hz.

x

2o-3l4n D x 12-\l2tt H.

kg).

discontinue

watts.

50

watts.

135 VAC),

new

50/60

Hz.

@

-

TROTJBLESHOOTING

This

section of the Manual
The first
mation,"
may
Terminal.

part,

describes

occur

titled

during

"General

what to

or right

is

divided into

Troubleshooting

do

about difficulties

you

after

assemble

four

parts.
Infor-

that

the

The
Waveforms,"
and their respective
blank,
waveforms.

third

always

section,
provides

test

check the

Page33

titled "Troubleshooting

several

important

points.

horizontal

If

waveforms

the

CRT screen is

and vertical

svnc

The

second

problems

lists
"Possible

sociated with the

the circuits involved

will help

this
and

Circuit

part,

titled

or conditions

Cause"

column lists

problem.

you

relate a

Description.

"Troubleshooting

that might

the components

In

many

with the

problem

problem

Charts,"

occur. The

as-

cases, the name

are also

to the Schematic

given.

of

The fourth
plains

Refer to

of

parts

how to

the

on

part,

titled "Shipping

prepare your

"X-Ray

the circuit

Views"

Terminal

for the

boards.

Information,"

for

shipping.

physical

location

ex-

t"n"to

@

General

NOTE: The following checks will
you

apply them to one

1,. Recheck the

pencil
frequently helpful to have a friend check
work. Someone
may notice something
overlooked.

2. About
do not function
tions
can
connections
described in the
beginning of the Assembly manual. Reheat

doubtful connections. Be sure all wires are sol­dered at
nected.

3.

Check each circuit
no solder bridges between adjacent connec­tions.
clean soldering iron tip between the two
that are bridged until the excess solder flows
down onto the tip

on the Pictorial as it is checked. It is

of the kits that are

90%

and

soldering.

be

eliminated

places

Remove

part

of the kit at a time.

wiring. Trace

who is

properly

to make

"Soldering"

where several wires are

board foil to be sure there are

any solder bridges by holding

of the soldering iron.

familiar

not

you

due to

Therefore,

by a

careful

sure

Troubleshooting Information

be

most effective if

lead in colored

each

with

have

returned

poor

many troubles

inspection

they are

information

your

the

unit

consistently

for repair

connec-

soldered as

at the

any

con-

points

of

Be

5.

6.

sure each diode

positioned

end

Check all component leads
cuit boards. Make sure the leads
through the
with

7.

The

other connections or

components listed

circuit board

column of the
most likely

causes
causes) of a
components, look first

Parts installed

pertains

This
trolytic

and tantalum capacitors,

is

installed with the banded

correctly.

connected to the cir-

and come in contact

parts.

"Possible

in the

"Troubleshooting

(but

not necessarily

problem.

When

for the following items:

incorrectly

especially to diodes,

do not

extend

Cause"

Chart" are the

the only

you

check these

or backwards.

and trans-

elec­istors.
Unsoldered

Reheat

the connections in the area of a

inadequately

or

soldered

parts.

problem.

a

Incorrect
part

numbers

interchanged parts.

or

on the diodes and

Check the

transistors.

4.

Check each
that is discolored,

bulging would indicate that it is faulty and

of
should be

resistor value

cracked,

or

replaced.

carefully.

shows any sign

or

A resistor

NOTE: In
resolve
information inside

"Warranty"

an extreme case where

a difficulty, refer to the

is

located inside the front cover.

the

rear

cover

you

are unable to

"Customer

the Manual. Your

of

Service"

ry

-

POWER

SUPPLY PROBLEMS

CONDITION

1. Nothing happens

2.

Fuse blows.

3. No s-volt output
low).

TROUBLESHOOTING

at turn

on.

or s-volt supply incorrect

(too

high

or

too

CHARTS

POSSIBLE

1. Terminal not

2. Fuse

3. Primary/line

4.

5. Fuseholder wiring.

6. Power

1.

2.

3. Short circuit

4.

5. Check for

6.
7 .

8.

9.

10.

1. |c101,lct02.

2. D101 - D104.

3. C1.

4.

CAUSE

plugged

F1 blown.

Switch 51 wiring.

Check
Short circuit on the

Shorted rectifier

and C105.
Shorted
Check
sink.
Incorrect
Power
Shorted regulator

+s-volt

cord wiring.

transformer T1.
primary

wiring.

across lransformer

shorts at the outputs

regulators.

for

a short between

fuse.

transformer.

reference

in,

power

supply circuit

diodes. D101-D1 12.

of the bridge rectifiers.

1C101,|C102,

the collector of

outputs. P101-1 , -2, -3, -4, -5, &

(ground)

$

not

board.

secondary.

1Cl03.

Q101 and

grounded

at P101-6.

C1, C2,

the heat

'1

.

-1

4.

+12

No

5. No - 12 volts,

6. No

7.

No

No

8.

CAUTION: Measure the
high voltage

volts,

or it measures too

or it measures

+26

volts,

or it measures

+36

volts,

anode voltage when

or

probe..

it

measures

high

too high

too high

too high

other voltages

high voltage only with an

low.

ortoo

low. t.

or too

or too low. 1.

too low.

or

are OK.

approved

1. lf

2. lf the

+26-volt

the

will

also be

26-volt supply is

reference

1c105.

2.

R105 and

3.

D109 - D1 12.

4.

C107 installed

-

5.

2. R103

3.

4.

5.
't.

2.

3.

1.

2.

3. 1c301.

4.

5.

12-volt

tc103.

and R104 interchanged
Q101, Q102.
D105 - D108.
+26-volt

c2.

D105 - D108.

Transformer

Flyback transformer T2.
Q1, Q307.

L301, deflection
Shoried

supply

low.

ground.

interchanged

R106

backward.

reference

reference

T1.

yoke.

foil

on the video

is

+15

below

OK, check 1C104 and the

volts,

or wrong values.

ground

ground

grounded

not

or wrong value.

grounded

not

circuit board.

+12-volt

the

at P101-6.

at P101-12.

supply

+12-volt

Pase36

@

CONDITION

9.

10.

VIDEO

CONDITION

1 1. No video

12.

-150

volts is incorrect.

+400

volts

is incorrect.

RELATED PROBLEMS

(blank

screen).

Screen all white

(raste|.

POSSIBLE

1.

2.

1.

2.

3.

POSSIBLE CAUSE

1. Anode voltage incorrect,

2.

3. No

4.

5. lC222A

6. Videoiblanking

7.

8.

1.

2.
3" tc222A.

4. Videoi

5. Brightness

CAUSE

D304.
c323.

R335.
D305 - D307.
c324 - c327.

Grid voltages incorrect

cathode drive.

Q308, Q309.

Brightness control
lC217A

Check
Q308 or Q309 shorted.

blanking chain on the character

out

1Viffi

(blanking in).

grid

of character

chain on the character

R338

voltages.

control R338 turned up.

(G1,

G2, G4).

generator

turned down.

circuit board).

qenerator

generator

circuit board.

circuit board.

13. lnsufficient

14. A

single bright horizontal line

15. Too

16. Too much

17. No horizontal

18. No vertical

brightness or contrast. 1.

much or too little heioht.

to little

or

sync.

sync.

width.

Q308, Q309.

2. R342, R343.

3. C328, C329.

4.

Check

appears on the screen. 1. Vertical

2. Deflection

3.

Q301 - 0306.

4.

lC221A

1C216 (sync/frame

5.
board.

1.

Height control R303

2.

Q301, Q302.

3.
'1.

2.

3. Deflection

4. Flyback

1.

2.

3. 1c301, lc2114.

wrong value

C303
Adjust

C321.

R325.
C312,C314.

1. lc221A.

2.

Q301.

grid

voltages.

amplifier.

yoke

(vertical),

(V

sync)

on

counter) on the character

or installed

jumper.

width

yoke

1301.

or

transformer T2.

the

character

misadjusted.

backward.

generator

circuit

board.

generator

circuit

CHARACTER

WRITING

PROBLEMS

CONDITION

19.

Characters don't

write

on

20. Wrong characters write

the

screen. 1. Duplex

the

on

screen

POSSIBLE

1. DAV latch
DAV

3.

4.

Three-state enables

5. RAM WE. OC

6. RAM

7. DAV from lC719C, lC725A, lC713C.

8.

Special
(A1

or

1. Keyboard

2. Keyboard

3. Bus wires interchanged.

4.

Bus wires shorted to + or

5. Bus

buffers

6. Shorted bus

7.

BAUD rate set wrong.

21. Screen filled with same character. 1. RAM

2. Keyboard

P402-8 always logic 0.
Check

Parallel input

3.
above.

4.

UART ilDE enable always on: Check
above.

CAUSE

switch

(1C616)

priority

F. OC

character

A2 high).

encoder
buffer

in

No DAV

-

encoder

(1C61

(1C6088,

if

DAV timing

if DAV riming

generator

1C402.

1C403.

when it

signal.

1A,

C,

C, D).

pulse (lC737A).

pulse (1C7198,

l@04, 1C405, 1C406 latched

"full"

position

ground.

1C603, 1C620.

foil.

counters

not

counting:
tc722o, D.
tcs02.
tc219F, tc217D.

output enable always on:

DAV latch

and three-state enables

tc616. tc608. tc610. tc619.

enable always on: Check

"half".

should be

D, lC610D, lC619B).

items listed

items listed

in

D).

under

under

on

2
2

22. Same line is repeated 12

23. Blocks

24. Writes

25. Characters write

26. Misses

27.

28. Writes

of characters are repeated

two characters. 1. Full Duplex key

erratically.

characters coming from the

Characters

write in more

control characters.

times. 1.

left

right. 1.

to

computer.

than one

position

on the screen. 1. Address

+12

2. 1c519,lC511C, rcs158, rC716A, rC715C.

2.

'1.

1. Refresh interrupt not

2.

counter not cbunting up.

+4
1c513, lc5148,

duplex
Wrong baud rate.

switch. Connect
great€r

At 110
stop

counter

(pushed

than

baud, the

bits.

not

counting.

600).

lcs10C.

set

in).

the

encoder.

for half

enabled at the

gr6en

wire to lug 2 of SW2

computer

(released)

duplex

may not be

rear

programmed

1C512, lC526A, lC526D,

2. RAM address lines shorted or open.
"Conditions

3. Counters

4.

Check

+4, +4 + +12, +QQ e +12,

't.

Control character decoder.

not

counting up

the counter cascade controls.

(see

lC73O,1C724

etcl.

lC703C, lC703B, lC707C, and

tc702.

2.

Control character detector.

lC617A.

baud

full

rate

rates

instead of

pqnel

(for

BAUD

lor two

& lC527B.

22 & 23" above).

+

(+20

Pase38

@

CONDITION

29. Writes wrong

30. Cannot write from the keyboard.

31. Control characters

character

do not blink in

CURSOR PROBLEMS

CONDITION

No

32.

cursor. 1. Cursor coincidence

33. No
screen.

34. Cursor controls will not move

cursor

movement

from keyboard

plot

mode. 1. No

when characters are written on the

cursor.

POSSIBLE CAUSE

1. Shorts between the X and Y scan and address lines
keyboard

2. tc402, 1c403.

1. No

2. Keyboard

2.

Control character video/decoder. lC201A, IC2O7B, lC210D,
tc219D.

POSSIBLE CAUSE

2. TPU cursor

3. Character
tc218B.

No

1.
+20

2.
+20

3.

1. 1c727.

2. No 1C

3.

Cursor

4. Q401.

encoder. 1C402.

(OE).

enable

output

3.75

-:20
counter.

count uo defeated. lC708D. 1C720. lC729A.

harness

bus

Hz. lC741D, 1C401.

gates.

generator

count up.

1C502.

pulse.

1C728.

movement latches

lC608D, lC611D, lC6198, 1C616.

plug

P402 disconnected.

gate.

lC710C,

cursor chain.

lC734B

1C508, 1C520.

1C503,

lC710D.

lC2O2, IC?O1C, lC208A,

(1C

if

the keyboard. 1C407, 1C408.

on

lC722B,lC729A

DAV),

of

the

35. Cursor

moves

continuouslv. 1. Cursor movement latches not

z.

Make sure
1c408.

36. 960 cursors 1. lc710c.

2.

Character
lc218B.

37. Wrong cursor movements from cursor

38. Wrong cursor movements from

ASCII

controls.

data.

1.

2. Wires in

'|

.

plugged

5701

Special character
lc703D, tc707c, tc72o, tc740B, tc740c, tc740D,lc721c,
IC721D,lC708D.

39. Cursor

40.

won't home.

moves

Cursor

Terminal is NOT in

on control characters

the

plot

mode.

rubouts when the

or

1. Cursor home switch.

2.

Cursor

Cursor latches. 1C501. 1C518. 1C512.

3.

4.

Select, select cursor, or select scroll

lc734A, lC504A, lcsosD, lC529B, lC529C,
tc524B,tc524c, tC504D, tC517c, tc517D, tc528A,

'1.

Control character detector.

2. Rubout

3. CC+ R decoder.
+20

4.

count uD deteat.

TPU

cycle

13J.

generator

plug

cursor chain.

in

backward.

5701 interchanged.

movement circuits. lC703A,

latch enable. 1C728.

detector.

1C613.

lC703B, lC703C,

lC708D. 1C720.

being

resets

lC617A.

reset. 1C407, 1C408.

four latches. 1C407,

all

lC201C, 1C202, lC208A,

lC703B,

lines. lC706A, lC71 1D,

rC51

1C797, lC7O2.

lC729A.

1C,

lc528B.

tC524A,

ry

-

CONDITION

41. Multiple cursor movements.

42.

43,

44.

45. Cursor dosen't home

I/O

PROBLEMS

CONDITION

does not blink for hold screen.

Cursor

No cursor
space

Cursor
a scroll.

movement on line feed, carriage

(control

(or

the blank

H).

line) moves

to

following the

return, or back

the wrong

page

erase

position

function.

after

POSSIBLE

1. Cursor movement latches on

1. No 3.75 Hz. 1C401 .

2.

3.

CAUSE

1c407. 1c408.

tc741c.
Cursor chain on character
lc201c, lc298A,

Q401.

rc218B.

1. Special character detector.
lc61 7c, lc61 7D, lc624o, lC624D.

2.

Special character

tc707c,

3.

Speciaf character latch. lC72O, IC74OC,

1c702.

tc721D,

4.

No 1C

signal.

'f

.

More than

decoder. lC703A,

tc708D.

1C728.

one scroll count up.

1. tc723B, tc740A.

POSSIBLE

CAUSE

the keyboard

generator

circuit board.

circuit board.

1C202,

lC617A, 1C614, 1C623, lC6178,

lC703B, lC703C, !C7O4B,

IC74OD, lC721C,

lC73O.

1C506, 1C522,

1C724,

46.

No serial input or

47.

No

serial

48.

No TTY input.

49.

No TTL input.

No input

50.

EIA input.

parallel

from

output

or UART.

(general).

Serial cable incorrectly wired.

1.
l/O

2.

3.

4. No

5.

6.

7.

8. Reader

1.

2.

3.

4.

1. Jumper wires

2. D603, D602 installed

3.

4.

1.

circuit
uration.
Wrong

baud

baud rate.
UART 1C612.

pins

UART
Off Line key

grounded

Jumper wires incorreclty installed.

D604, D602 installed
Q603.

Check

the

Q603.
Check the DAV

Jumper wires incorrectly

2. tc609c,

3. Check

',|

. Terminal

2. Plug P601-23

the DAV output

not

board

rate.

1C601,

NP, NBl, NB2,

pushed

start must be

or current must

DAV

output

incorrectly installed.

output of lC719C

tc609D.

in hold

screen

shorted to

jumper

wired for

lC6O2, 1C607,

or EPS incorrectly wired (umpers).

in.

operative

flowing in

be

backward.

lC719C

of

backward.

the

|C6O8A.

(Q604

the reader

(DAV'),

(DAV'),

proper

must have the

lC725A, lC713C.

lC725A, lC713C.

installed.

(DAV'),

lC719C

of

mode.

ground.

lC6158. lC615D.

lC725A, lC713C.

serial config-

base

loop).

start

Pase4o

@

CONDITION

5'1. No EIA output.

52. NoTW

53. No TTL

No

output.

output.

parallel

input

or output

(general).

POSSIBLE

CAUSE

1. Jumper wires incorrectly installed.

2. Off Line

Break keys

or

pushed

in.

3. lc609A, lc609B, 1c604.

4.

Q601, Q602.
D605 installed

5.

1.

Jumper

2.

3.

4.

Line

Off
rc609A,

0601. 0602.

5. D605 installed
'1.

Jumper wires incorrectly installed.

2.

Off Line or Break key

backward.

wires incorrectly

or Break key

wired.

pushed

tc609B, tc604.

backward.

pushed

in.

in.

3. tc609A. tc609B.

1.

Check all

handshakes:

6FV, - tc61gB, tc624t,tczo2.

OnV,
H6lTo - From
m-M - rc61oB,

IC61OA,

-

1615D, Hold screen.

the external device.

lc61sA, tc61sB,

tc618A, 1C619C, tC624B.

2.

Check

1c611,

3.

Check for defective

the

tc610D, tc6198, rC608B, rC608C,

data

priority

or

latch

and encoder.

incorrec{ly

wired interconnect

lC615B, 1C616,

tC608D.

cables.

parallel

55. No

56. No

57. No handshake.

58.

No echo

59.

Stays off line

60. Reader

61. Wrong

input.

parallel

output.

back on full

start doesn't

baud rates even if

correctly.

or won't

duplex.

go

line.

off

work.

the Terminal is

programmed

1.

Input buffer. 1C620, lC608C.

2.

xBE' 1c707A. lc713A.

3.

tc702.

1.

Output latches. 1C621 , 1C622.

2. Load

parallel

signal from 1C702.

3. Check the handshakes

4. XBE' lC707A,
(XBE

TBMT
three

signals must be high for

1.

Check

1.

Computer not

2. No

1.

2.

3.

4.

1. Install

serial

Off Line switch
tc609B, lc609D.
Q603.
D602

delective

a

lC713A. XBE' is

parallel

),

handshakes

for

set

input.

on

or

jumper

from

FDTI

(see

echo back.

the keyboard.

installed

the base to

external current loop.

2. D603 installed

rc606,

3.

4.

Q604.

1. 1c601,

2. 4800/9600

backward.

tc707A,

tc713A.

1c602, tc607A, tc608A.

lines interchanged in harness

baud

3.

(see

item

backward.

item

54 above).

generated

lXae,;,

XBE'.

above).

il

ground

from the

and reader

of

Q604

if there is no

P601-2, P601-

UART

control.

Ail

62. No

baud rate

output.

1.

2.

item

Check

rc607B,

tc607c.

61 above.

@

-

Page41

MISCELLANEOUS

CONDITION

No

63.

erase to end of line. 1.

64. No erase

65. Erase

66. No

67. No erase

page.

continues

scroll.

on scroll.

PROBLEMS

(blank

forever

screen).

POSSIBLE

2. Erase flip-flop is not

CAUSE

Space
generator).

generator

1C404, 1C405, 1C406.

on the keyboard

being set.

3. A write is not turning on the
lc737 A, lC737

4. RAM counter

1.

Check the

2. Erase filp-flop is not

flip-flop lC723A is not

Erase

2.

1C730

1.

Scroll

2.

Cursor/scroll coincidence

rc733A,

+12

3.

tc735B. tC735D.

4.

Scroll
tc741B, tc742c.

1. lC722A not

2.

Gheck

3. 1C724

count up and the scroll erase,
count up or the scroll erase work).

timing

or

key not

lC733B, lC705C, lC710B.

+4

or

logic. lC7158, 1C739, lC733C, lC733D, lC741A,

the items in condition

(since

lC7 17F, lC726A.

C,

is

not counting up on erase. lC722C, lC737B.

items in

condition 63 above.

being set by

signals.

pushed

in.

up not

count

sefting erase

the

same

being

flip-flop.

pin

(special

A1 : 0, A2= 1 for a

lC737D,

space

being cleared.

is

not being clocked

clocked into

64

1C724 controls both the

ot

1C724 is

(A2)

lC715A.

above.

lC723A.

or enabling

lC709A. lC735A,

if

OK

character

space.

RAM WE.

into lC709B.

scroll

either the scroll

68.

The
the wrong

erased

line,

the erased block, or the cursor move to

position

after a

scroll operation.

1. No

scroll count up.

2. No count
same
scroll

erase,

erase work).

3. The 47 O resistor
chassis

69. Scrolls regardless

70.

No short form. 1. Short Form key.

of

the

position

ol the Scroll

key. 1.

2.

2.

Scroll
Scroll

Counter controls.

3. Counter

lC514A, lC514D
lC530A, lC530D

4.

Check

71 . No long form. 1.

2. Counter controls. 1C724,lC73O.

3. Counter

4.

No

auto carry.

1.

2.

3.

Form key.

Short

lC514B,
lC51 1A, lC511C

Check

Auto Carry
Counter controls.
Counter not

No
No carry outpul
Counter multiplexers
lc530D, rc528D.

1C506, 1C522.

up scroll

pin

ot 1C724 controls

+4/scroll +

1C724 is

between

is missing.

key.

(see

logic

condition 66 above).

1C724, lC73O.

multiplexers

+20

counter.

multiplexers

lC514C

+20

counter.

pushed

key not

1C724,lC73O.

counting

carry output

12

both

if

OK

eitherthescrollcount up orthescroll

plug G pin

the RAM

on

trom 1C724

signal

the

scroll

5 and

counter circuit board:

and

(since

count up

plug C pin

(+2O + +121.
(+'12+

+4).

1C502, 1C509, lC510B, lC510C.

the RAM

on

+

(+lQ

+

(+4

1C502, 1C509,

-'121.

counter circuit board:

and

-4).
lC510B, lC510C.

in.

up:

+4

(long

trom
from

j-20

form) lC515B, lC530B.

(short

form) lC510C.

1C514, lC511A, lC51 lC, lC530A,

the
the

and

5 on the

Pase4.

@

CONDITION

plot.

73. No

74.

Plot line

75.

No repeat

76.

No cursor

77.

No relresh interrupt.

78.

Screen blinks

79.

No hold

80. Locks

appears

screen mode.

uo in hold

in

wrong

(characters

reoeat.

low

at

baud rates.

screen mode.

place.

or cursor).

POSSIBLE

1.

2.

3. Plot video. lC210B, lC208A,

4.

1.

2.

1. 1901.

2. Vn'

3. D401.

4.

1. D401.

2-

3. R403.

1. No refresh interrupt

2. Rear

3. tc705A, tc706B.

1.

2. tc705A.

1. tc733c. rC733D.

1.

CAUSE

Plot key not

plot

No
tc219A.

tczzlB, tc221?.
Plot

Plot inverters.

Repeat

Q401.

Rear

pushed

in.

coincidence.

coincidence. 1C206, lC209A, lC209B, lC209D.

input to keyboard

Key.

panel

Baud switch not wired

panel

Baud

1C206,

lC209A, lC209B, lCzOgD,1C212,

1C212, lC219A.

open

signal. lC610C, P601-21,

switch wired for > 600

tC739A

tc739B. tC739D. tC739A.

tC739C

lC218A.

5703-3.

correctlv for > 600 baud.

baud

81. No transmit

82. Transmit

83. No

84. No

85.

Screen is

86. Cursor

page

end of line

bell from

not erased when

is moving

page.

won't

bell.

control G.

when

stoo.

the Terminal

the Terminal

is

lurned on. 1.

is turned

on.

1. XP flip-flop not

2. 7C

3.

4.

1. lc7259.

2.

1.

2.

3.

1. Bell

2.

3. Monoslable

4.

2.
'1

.

2. XP

oulse.

No OB2XP load

pulse

OB2
Count up not happening:

Transmit
release

End
Monostable 1C736,
Speaker driver lC742A.

tc724B.

Speaker driver
Power

lc717E, D701
Erase

Terminal is in
reset.

into 1C702.

Duplex key in Full

(released).

Duplex
1c704.
tC725A,

lC721A.

page

the Scroll

line

of

decoder. lC7168.

detector

1C736, R717,

up reset.

circuit. lC715A.

(1C731C,

flip{lop

being set. lC731C, lC731D, lC732C,lC732D.

pulse.

lC701A,

(fake

lC719C

was started in the

Break

or

R717,

the l/O

on

.

transmit

circuit board. lC617D,

lC742A.

Q701

,

lC723A.

page

lC731D)

lC701B, lC704A, 1C702.

(pushed

Duplex

DAV).

hold screen mode. Press

keys to

exit

lC716C. lC718A. lC735C.

C7'17.

C717.

lC717A, lC717B, lC717C,

mode.

did not

the

get

reset

in) instead

transmit

1C614, 1C623.

by the

page

of

mode.

lC717D,

power

No

Half

and

up

@

-

Page43

TROUBLESHOOTING

you

If
waveforms.
the
Timing
Pages
also help
the Terminal functions.

6V

4V

2V

encounter a

Use a dual-trace

time-related signals to

Diagrams

3 through 6) and the

you

understand the

problem,

#7 - #4

(in

s20?-2:,P302-8

HOR IZONTAL

oscilloscope to compare

the

the

Circuit Description

timing

WAVEFORMS

check the following

TPU

timing signals.

Illustration

relationships

SYNC

-l

Booklet,

will

of

()V

?12.9

-USEC

Vo

lts

/c

m

51.6 SEC

Time/cm

l0uSEC

Pase44

@

ImSEC

-4.

I

ImS

c

2

,r-l

J,F

-]

ry

L

Volts/cm

l2.4mSEC

-i

'-r

(

VERT

s202

+

I4.

RT

SY

BLAN

s20

l

-4

-13

mSEC

c

Time/cm

2mSEC

I

_l+t-

Volts/cm

s

70

IO

v^l

tr

s703-1,

szoz-tt

,

Time/cm

5mSEC

E

ilJ

V

1-r

r

t_i_l

-2

-1j..^

-L-2_r

LqJ il-l- ilr

Volts/cm

This is the basic troubleshooting
triggered externally

(-

Vn'
until the trace

pulse

trigger).

(0

thru 7J in

Decrease the horizontal

appears as shown.

its

(EXT)

own centimeter

from

Vp

This

waveform.

(+

trigger) or

sweep

puts

division

vernier

each

(pulse

It is

from

TPU

Time/cm

in the first division,
division, then

This lets

etc.).
the various

0

for the

location of

50USEC

through

each

pulse

TPU

a repeat of

you relate other

TPU cycles.

(urucnl)seetexr

pulse

7 in the eighth

in the ninth division,

0

sequences

Schematic

point.

test

Refer to

pulse

timing

the TPU

to

Page

46

SHIPPING INFORMATION

In

an extreme

difficulty,

your

to
Heath

If you

board,

This

local Heathkit

Company.
can isolate

take

will save

Whenever
cuit board)

for

service.

cations

However,
unit

of the Electronic

if it becomes necessary to

to the Heath

7. Remove
part.

2. Remove
send this
damaged.

case where

you

may want to take

Service

problem

the

(or

send)

only

shipping cost and

possible,

to

Consult

take

your

local Heathkit
your

Company,

the cabinet shell. Do not

the

CRT

part.

you

are unable

your

Video Terminal

Center or ship it

particular

to a

that

circuit board

service expense.

your

Video

Terminal

Electronic

Heathkit

Catalog for

Centers.

ship the complete

do it as follows:

from the chassis.

Store it

where

to

for repair.

send

it

will not

resolve

to the

circuit

(or

cir-

Center

lo-

the

this

Do not

get

a

IMPORTANT: Include the
with
and repairing

Tape

speaker to

Install

6.
and hardware.

Refer

7.
tion inside

carefully

two circuit

your

Terminal. It will be helpful

your

a. The

b. Name and model of

c.

d.

problem you

Name and model of the cassette
used).

Name and model of
reader/punch

a small

all remaining

to the "Customer

piece

of cardboard over the

protect

the rear

pack

boards as instructed.

unit.

the speaker cone.

cover of the Manual and

the Video Terminal

following information

are having.

your

(if

used).

panels,

Service"

computer

the

components,

informa-

and the

in diagnosing

system.

recorder

paper

tape

(if

3.

Remove

(the

the angle brackets from the

brackets that

CRT). Do not send these

4.

Remove

the Video circuit board

circuit board from
wrap these
from

being

circuit boards to

damaged.

support the top

parts.

and the I/O

the chassis.

Carefully

prevent

chassis

of the

them

Amount of memorv.

e.

f.

a
o'

h.

rate.

Baud

System configuration.
Any additional

describe

your

information that

system.

will help

CIRCUIT

DESCRIPTION

Refer to the Schematic
Diagram
this

To
the
C101, L301,
istors,

Sroups:

The Block

can
coordinate
bus. These blocks,

generator,
the
ASCII bus. Data

another and to the external devices

under the control of

(TPU).

cuits, a line operated

tage

ated

The

dividers that

functional

the character

(Random

parallel

The serial dot information

the raster scan on

(Illustration

"Circuit

help

Schematic,

1-99

100-199

be

divided

I/O

Other

power

from the video circuits.

character

Description."

you

locate

the circuit

etc.) for resistors,

and

integrated

Parts
Parts
circuit board.

Diagram shows

into a series of

the movement of data on an 8-bit

the RAM

(Input/Output),

is

functional

supply, or

generator

generate

modules within the Terminal.

generator

Access MemoryJ

ASCII information

Diagrams and to the

Booklet, Page

specific

on the
on the

the

parts

in

component

capacitors,

circuits

which

and

counter,

are connected directly

transferred

the timing and

blocks

power

flyback

has a master oscillator

the

takes data

CRT

are in

chassis.
power

how

the

functional blocks that

include

include the

supply, and a

system,

timing

and converts

to

serial

is

then

screen.

Block

you

7)

while

the Terminal

numbers

coils, trans-

the following

supply

read

or

on

(R1,

BASIC OVERVIEW

Video Terminal

ASCII

the character

the keyboard, and

to the

from

over the

processing

signals

from the RAM

dot information.

used to

block to

one

ASCII bus

video

high vol-

which is

for all of the

Basically,

it from B-bit

modulate

unit

oper-

cir-

and

The video

the CRT.

200-299

300-399

400-499

500-599

600-699
700-7gg

Each

of the

separately.

converts
generator

lator and amplifier
and drives
contains

the

drives
vertical and horizontal
by sync

The Ram and counter

the

stores
Everything
stored

also

board

latch,

sor
posed

to appear on

remember

keyboard

The

a series

and

Parts

on the character
circuit
Parts on
Parts
circuit board.
Parts
circuit board.
Parts
Parts

circuits listed

module contains

the

into

video circuits

The

the

the

horizontal flyback

pulses

information

that appears

in the

contains

which

the start of

of

board.

on the keyboard

on the RAM

on

on the TPU

TTL dot data

voltage levels that

that

vertical

horizontal oscillator

generated

board contains

RAM.

other

The

the

remembers

the

contains

special

video

the

the I/O

generates

portion

oscillators

by

be displayed

to

on

RAM address

screen,

page,

a

circuit board.

and counter

circuit board

circuit board.

above will

a video amplifier

from the

drive the cathode

also have

the CRT

of

and sweep

the character

face of

the

and

RAM

where

and scroll

or scroll

standard

function

generator

be described

character

a vertical oscil-

vertical sweep

the

yoke. It

and driver

systems.

synchronized

are

generator.

memory

the

on the

the

counter

counter,

the cursor

counters that

information.

ASCII

keys that

keyboard

that

of

also

that

The

that

screen.

is

CRT

circuit

a cur-

is sup-

control

the operation of
control
tion of the serial
mode
generator
bus

The
parallel data transfers

external
asynchronous

rial data transfers

keys, a number of

keys.

whenever

I/O board contains

devices.

the Terminal.

I/O,

It

also

puts

that

selected

it is required.

It also contains

receiver/transmitter)

between

It includes

keys that control

keys, and screen display

erase

includes a special character

ASCII information

Terminal

the

and
the

the UART

latches

between

five

the opera-

buffers to

Terminal

that controls

and

(universal

and any

cursor

the

on

control

any

se-

ex-

ternal devices.
character

special characters such

trol characters, etc.

The

timing and

the

other

module within the Terminal. Data

or transmitted under the control of the
tion

of the front

also

controls

erasing, and the

The I/O

detector that

functional blocks. It is the decision-making

cursor movements, scrolling operations,

circuit
monitors the

processing

panel

RAM

board also

bus and looks

unit

returns, bells, con-

(TPU)

is moved.

and the

as carriage

switches

counter configurations.

has

a special

for

controls all of

written,

TPU as a func-

itself. It

data

POWER

primary

The
blow fuse
primary

of the

F1, ON/OFF switch SW1, and

windings
ary windings may be
operation

The
supplies

red

secondary

g

or in

volts
through D104. The rectified
rectifier is filtered

Integrated

circuits IC101 and ICLOZ
lated s-volt supplies. The integrated circuits are
ternally

protected
and high temperature.
stabilize

The
to

diode
volt
capacitor
of the

the regulators.

orange secondary

bridge rectifier

output

of the bridge

C2. This

power

supply.

power

supply consists

of slow-

the dual

transformer T1. The

of

connected

parallel

winding

for 120-volt

in

of the

series

power

AC to the diode bridge

output of

dual

for 240-volt

operation.

transformer

rectifier

the

by capacitor C1.

provide

two

against short circuits, overloads,

Capacitors

winding

D10b

36-volt

rectifier

supply is one

C101 and CtOz

supplies 28 volts

through D108.

is filtered

of the outputs

The 36-

prim-

D101

bridge

regu-

SUPPLY

in-

AC

by

IC103

is a 2O-volt regulator,
grammed by resistors
volts. ICto3 draws
transistor
rents
output
limit
Capacitor

ICl,04
from the
bility

The

diode
output
negative,

Q101. Q101

required by the

26 volts. Transistor

at

the short circuit

C103

is a 12-volt

26-volt supply. Capacitor

for IC104.

green

secondary

bridge

voltage

adjustable
grammed to
Capacitor
C107

Resistor

secondary
CRT

C106

lowers

R107 reduces the 15 volts AC from the

winding

filament.

its

video

provides

regulator.

winding

rectifier

is filtered by capacitor

voltage

-12

volts

provides

the high

to

its output

but

to supply

R103 and

input current

in turn

current

stability

R104

from the

provides

circuits and

and

Q102

about

to

for IC103.

The input

to this

C104

supplies

the

regulates the

resistor

provides

15

D109 throughDttz.

C105.

regulator

for

output

VAC

11

R105

IC105, while

to

by resistors

stability

frequency

provide

pro-

is

26

base of

larger cur-

R102

2 amperes.

IC comes

sta-

volts AC to

DC

The

IC105 is a

pro-

is

that

and R106.

impedance.

green

power

the

VERTICAL

beginning of

At the

pulse

sync

cal
charges

the voltage

of the sync

current

stant
coupled
the

source,

cunent.

through

base of

SWEEP CIRCUITS

vertical scan

each

turns on

transistor

across capacitor

pulse,

charges

This

resistor

transistor

turns off.

Q301

capacitor

generates a linear

R307

Q303.

VIDEO

cycle the

Q301.

C303.

Transistor

C303

ramp that

and capacitor C304

verti-

dis-

This

At the end

Q302,

with a con-

CIRCUITS

Transistors
ventional
drive the vertical
ples

the current

feedback voltage

a

R315 to the base

increase

is

tremes of the scan. This, in
linear from

to

vertical

Q303, Q304, Q305,

class B amplifier that amplifies the ramp

the amount

the top to the bottom

rate

scan

deflection

yoke.

through the

through

of

divider

Q303.

feedback

of

Diodes D3O1 and D302

is 60.5 Hz.

QgO0

form

and

Resistor R323

yoke

and

provides

R313, R314,

applied at the ex-

effect,

keeps the scan

the

of

screen.

a con-

to

sam-

a

and

The

--

ry

page

49

HORIZONTAL

horizontal

The
triggered
quency of
and
horizontal
coupled
IC301,
voltage

and oscillate

The output
which,
tor,

Q1.

determined
drives
former

internally

When

rapid collapse

the
erates
Capacitor

this

of
linearity
and
maximum.

oscillator,

this oscillator,

capacitor

C312,

sweep

through

The sync

causes

that

at

(pin

in turn,

The duty

by

primary of

the

The

T2.

provide 12

to

the horizontal

2oo-volt

a

C321

pulse,

coil

C321

L301,

capacitor

The current
is considered
through
negative
to

side of
to

same

Diode Dr,

effectively
cuit.
charge on

the linearity

current

quickly

the CRT

collapse

direction.

As the

pull

it tries to

as

which

removes C321

yoke field continues

C322
produces a near
which causes
yoke

field decreases,

left toward

the

a

SWEEP

sweep

CIRCUITS

system

IC3o1.

which

is slightly

Horizontal

rate.

the

to

C314

pulse changes

oscillator

the

desired

the

of

1)

drives

cycle

R328

high

and

horizontal

IC301

the horizontal

(the

Rgzg.

horizontal

the

voltage

for the

kV

oscillator

flux in

the

of

pulse across the

charges

C322

immediately

discharges

then

horizontal deflection

the

until

through

negative

causes

the electron

screen

(flowing from C321

the

coil,

magnetic

the

beam

(retrace).

keep the

part

is

of

(shorts

continues

linear

linear

to increase'

change

change

the electron

the center

of

is controlled

free-running

The

resistor

by

is set

15494

the

than

less

pulses

sync

(pin

input

*Vcc

internal

an

reset

to

reference

prematurely

rate'

drives

on-to-off

transistor

output

ratio)

transis-

of

The collector

output

rectified

of

Q1

to the

is

the CRT.

to turn

T2

winding.

maximum

secondary

anode

causes

transformer

primary

quickly through

yoke

the

the

yoke,

The

current

Qr,

to

now
it out)

current

yoke

at this

and C322).

field of

the

the extreme

yoke

field

flowing

conducts

from

the cir-

to collapse,

This

(decrease) in current,

yoke field.

in the

moves

beam

the CRT

screen.

by

fre-

R325

Hz
are

6) of

Q307

is

Q1

of

Qt

trans-

off,

gen-

yoke,

is

point

down

This

yoke

left

begins

the

in

and

the

action

As the

from

Before
the screen,

yoke

the

transistor

current reaches

Q1

tal oscillator. Transistor

will

circuit. Current
collapses
will be at
stored

completely.

the center

in

C322
horizontal deflection
transistor
through the
C352
transistor

the circuit.

of
as the
moves
right side

Q1

yoke is considered

up through

Q1).

yoke

current

the electron

of the CRT

tinues to discharge

of the screen
repeats

HIGH

During

of

for

each

VOLTAGE

retrace, the

T2 is coupled

doubler D305,

provides

This

voltage

The
rectified

supply

VIDEO

video information

The
generator is a string

base of

to the
output

cathode

the
which

brightness

the

from

by diode

the

for

AMPLIFIER

Qgo9,

transistor

of the

the

sets

cease

At this

of the

now begins

yoke,

positive

in a

the

Diode Ds is now

The change

increases

beam
until

and

Qr

horizontal

SUPPLY

200-volt

through

and D307, C324,C326,

D306

a 300-volt

the

D304

control.

focus

1's and

of

which

Q308.

CRT.

voltage on

the displayed

of

zero

is turned

also keeps

Q1

flow when

to

point,

CRT screen'

to discharge

linearity coil

direction.

positive

yoke,

the

reverse

polarity

in

in a

the center

from

beam is at

the

scan

Capacitor

again.

line.

screen.

turns off

pulse

resistor

supply

for

blanking

produce a

to

that comes

This data

0's.

drives

The collector

The

grid

the emitter

brightness

t of the

characters.

at the center of

by the horizon-

on

C321 out of the

yoke field

the

the electron

The charge

through

L301, and

The current

(flowing

linearity coil,

biased

the

of

positive

and out

yoke

direction,

toward

C322

right

the

process

This

primary

across

the

R335

voltage

to

andCgzz

grid

winding

2 of

the CRT'

of

-150-volt

is coupled

of

Qgoa

control,

CRT,

character

of

drives

controls

from the

beam

the

from

and

field,

the

con-

side

Tz

video

R338

.

is

Pase'o

@

GENERAL
The

CRT

80 character

locations. See

DESCRIPTION

screen is divided into 12 lines,

locations, for

Pictorial 4-1.

BBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBBB

a total of

cccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccccc

DDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD
EEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE

ROW

GGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGCGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGGG
HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
JJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJJ
KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL

I

CHARACTER

GENERATOR

each having

gOO

character

80

CHARACTERS

AAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAA

FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

960

CHARACIER

LOCATIONS

Each location
address in RAM.
at

the upper
correspond
somewhere
correspond
location
arranged in
See Pictorial

corresponds

left hand

to RAM

in

to

address

on the

16 horizontal

+-2.

PICTORIAL 4.2

to a specific memory

For instance, the

corner of the screen might

address

the middle

screen is in

0000000000. A
of the

0111101011.
lines

character location

location

screen might

Each character

a 128-space

vertical

and 8

I6 HORIZONTAL

matrix

LINTS

PICTORIAL

rows.

i

I2

l3
I4
I5

4.7

8

VERTI

ROWS

CAL

0I23456701

@

-

Pictorial4-3 (Illustration

block

diagram

the

end

ofvertical retrace,

initialized

the screen.

960 RAM

the

ASCII

of the

to

the address

The

address

locations.

code for

the

character

Each

character

Booklet,
the

for the

counter

memory location

Page

generator

RAM

address

upper left

addresses

to be displayed.

8) shows
circuits.

counter

corner

one ofthe

contains

the

At

is

of

The

ASCII
generator.
of
ter
character
shown in Pictorial
word oOto00

code is applied through a latch

However,

7-bitASCII

the

generator.

generator

word areused to

Sixty-four

addresses the character H.

to the character

the

only

characters are stored in the

ROM, each at its

4-4. For instance.

least

six

significant bits

address the charac-

own address as

the 6-bit ASCII

Page51

CHARACTER

ADDRESS

Ao As

ooo

oo I

'o

I

oll

roo

rol
tto

ttl

As
Ae

Ar

Aa'

o

o

o

o

o

o

I

o

I
I

I

o

I

I

o

o

I

I

o

HHffiffiffiffiHffi
ffiffiHffiffiffiffiffi
Hffiffiffiffiffiffiffi

ffiffiffiHffiffiffiffi
Hffiffiffiffiffiffiffi
ffiHHf,ffiffiffiffi
ffiHffiffiffiffiffiffi

HHHffiffiffiffiffi

I

I

Character

ASCIT

CHARACTER GENERATOR

6-BIT ASCII WORD

BI

T

PICTORIAL 4.4

INPUT

H

6 5

Ae A6

o o

4

3 2

At Ao As Aa

I o

o o

1

t"n"ut

@

ROW

ADDRESS

000

001

010
011
100

t0l
tI0
IIl

Since the electron beam
line at a time, the
must be
this, the
a row for

shifted out serially, one row at a time. To

character

each character.

OUTPUTS

0r

0a 0

PICTORIAL

in

the

that make

dots

generator puts

Pictorial

OW O

4.5

CRT

out up to

outputs for the character H. The
always followed by three
before the

dots

for

the next character are shifted out.

spaces

(the

ALWAYS

IS

scans only

BLANK

one

up the characters

do

five

dots in

4-5 shows the row

S-bit dot data

absence of dots)

The

cursor
an unblanking signal is applied
This happens when
stored in the cursor latch, is
address coming from the

is

TECHNICAL

The master
the

character

posed
The clock frequency is
complemented
and the
277C, and 207,4'
from the master

for

#7
the waveforms,
transition)

is

logic level
mately 30 nanoseconds.

clock

IC210B,

of

other system timing. lC's 214,27OC,227D,

these waveforms.

of the clock
transitions

displayed on scan lines 12 and 13 when

the video

to

the cursor

RAM address counter.

location,

coincident with the

circuits.

which

DESCRIPTION

the

of

generator

crystal Y2O'1., and transistor

12.395 MHz. The true and the

outputs are

generate

clock signal. Refer

that the trailing

of

entire

circuit

provided

Terminal

board and it is com-

located

is

for

the dot clock

timing signals A, E, and F

to timing diagram

Keep in mind

edge

pulse

always

the

other

as

(the

preceeds

IC's

by approxi-

you

negative

on

Q201,

study

any

is

Since the CRT scanning

to

be applied to the

process

video
the s-bit dot data is loaded into a shift
shifted eight times. This shifts

followed by three

data
formed
circuits

when a blanking signal is applied to the video

during

spaces.

the fifth through seventh

requires the dots data

circuits in a

serial

register

the five bits

out

The three spaces are

format,

and

dot

of

shift
sequences. They are also necessary because the
character location on the screen has been defined as
being eight rows wide. The spaces

provide

space

between characters.
During the fifth through the

the
next
incremented
addressing

register is loaded with new dot data for the

shift

character.

The RAM

its next

to

succeeding

seventh

address counter

address.

RAM location and
dot data continues until a horizontal sync
generated
sync

at the

end of

pulse

increments the row counter and causes the

a scan line. The horizontal

electron beam to begin a new scan line.
generator

dot matrix, This

rows

now

outputs

dot data have been outputted.

of

dot data

process

continues until all seven

lines 8 through 15 are normally

will appear on lines 12 and
(16

lines) begins after scan

scan

13. A new character line

shift sequence,

is also

process

This

outputting

pulse

The

character

for

next row in the

the

Horizontal

scan

blanked. The cursor,

line 15 is

completed.

of

is

At

the start of the character

(on

counter
told by
After

565 nS, the RAM data is latched into

IC203

generator

ter
Eighty
the RAM
character
dot information
five bits

generator.

ter
shift registerlC2O4.

register

pulse

load

the RAM

the trailing edge of waveform F to count up.

and then

nS later, the

transferred to the input of the

by

the next leading

trailing edge

to count up again. In

generator

and, after approximately 450

dot

of

data appear at the

Waveform A is used as a load

The dots

by the trailing

goes

back to zero. Actually,

ter is loaded three times

load at t0 is

used.

The

shift dots out serially as

is

turn,
pulse,
provide

applied

waveform

inter-character blanking,

RAM data

in

used

increment the

composed of

to the CRT,

A is used as a

for

the character
IC's 215 and 220. After 80 characters

generation

and counter circuit board)

edge of waveform F.

of

the

is

starting to access its internal

output of
latched

are

edge of the dot clock before the

(at

t6, t7, and t0), but only the

next five cycles of the dot clock

information, which,

video

At the end of the

blanking signal to

generator,

character countet,

have been accessed and shifted out,

provides

ICz15
blanks the

retrace blanking signal.

a

video

during

the retrace

inhibits further RAM count-ups.

cycle, the RAM

is

IC2O2

and

charac-

waveform F

meantime,

tells

the

nS, the

the

charac-

pulse

for

into the shift

the shift

regis-

in

fifth

Besides latching

waveform

F is

which is

the D output of

This

signal

time and it also

Actually,
blanking directly.

in IC211 to allow time for the
to be shifted out.
blanking and sync
counter,
the next
blanking
all

characters have been shifted out,

of characters
next
and the same

but the

character lines.lC222C
put
appear
cycle.

At the end of the
(the
(divide-by-12)
row
sync or
number of
screen.

character

the vertical blanking signal.

conjunction with
ate the vertical sync
Refer to waveforms
#2

Cursor

into

This

duration of the character
appears
IC278 in the video chain.

If

the ASCII character latched in IC's 2O2 and 203
control character, bits o and 7 will
outputs
output
delayed by IC?O7B for the duration of the character
generator
information
input
will unblank the control character dots 4 times a
second,
the screen.

the D output of

It is delayed

The

pulses

which tells the character

row

of dot

period
scan lines of

eight

eight scan

video is blanked

IC273 so that

of

in scan

row counter)

characters.

of 80

frame

At the end of

row, the C and D outputs

for a description of

information from the RAM and TPU

IC202 along with the ASCII data by waveform

cursor signal

as

of

of

access time and it is used to blank the dot

IC207B is

of

causing

is

over,

is displayed

lines, the

80 characters are shifted out once

rows 12 and

16th scan

counter in the

counter,

rows

the latches will both be high causing the

IC2O1A to

characters that are displayed

of

the vertical blanking

video

information at

for that control character.

driven

the

IC215

by

last

outputs

and count

information. When the

process

the

information for the same

the screen. During

on

entire

provide

to

decodes

the cursor

13

line, the D output of

is used

It is also used

1C21.6,

the 16th scan

pulse

1 through 22 on timing

is

go

character to appear

to count up

RAM to access

which keeps track of

IC's

to start

the scan and

delayed

generator

to a logic 0. This logic 0 is

by

a4Hz clock

not turn

does

two character

character

of IC211A

IC2 13 , the row

up

generator

repeated until

is
and a complete
process

the

information can

the character

of

209C and 221,{,in

by IC208A for the

inputs 1 and 4

is

spacing
row counter out-

to increment the

line

of

IC216

of

signal,

vertical

frame cycles.

access

time and it

be 0 and the

The

pulse,

to blink

the

on

times

accessed

generate

to

access

retrace

80

row

the

repeated

again,

between

only

row

IC2 13

+12

the

the next

the
the

on
the tZth
generate

gener-

retrace.

diagram

is

latched

F.

of

is

preset

which

on

In
value

beam

a

Q

plot

the

display
of characters that would

screen is repeated 4 times,
scan
lines). In the space directly above

line
character.
128th
first line

line
character
would

character
be 75 and it would
Pictorials 1.-2
Page

The

IC216,

of
at the
are inverted
will
outputs
exclusive NOR gates (IC206

The

corresponding
and IC203.

exactly
logic 1
If

the
button
gated
delay
nal will
signal that
short dash. During the
tion is blanked by
dot information is

The video
into
channels. The

IC210D, ICz19D,

of
blanking signals
IC2O4
video
dots represent

mode, the first 128 scan lines are used to

information that

7-bit

of a

line

is turned

that corresponds

line

(128

appear at the

2).

four

end of the 8th

be 727

other inputs

will appear

plot

on the keyboard,
through IC201B
of one character time, the

three

will appear directly at

will be blanked by the output

ASCII word.

(in

the 9th, 10th, 11th,

to

on

display

The 128

(line

(line

lines

was a

was a K

outputs

count the

of the inverters

When

coincident

appear at

will then be

and blanking channels can be broken down

video

scan

127) is
is at the bottom

0)
from the top).

rubout, which

(binary

appear on

(Page

6)

IC213

of

scan lines from

character row. The

1C272

by

at the top

to the

bits

from the

the seven

with the

at the

function

the output of

the output of IC201D and

blanked by the

channels and two basic blanking
information video

dot

and

present,

a control character by

corresponds to the binary

In

this mode, the first row

normally be seen

starting

a lighted dash in the scan

to the binary value of that

lines

are arranged

at the top of the screen

very top of the screen.

1001011), its

and 1-3

and the A,

and IC219A

and 0

on the 127th row.

are

applied

and

gates

NOR

outputs

data bits at the

outputs

outputs

has been

this

the input

to

displayed on the screen as a

plot

time, the cursor informa-

IC218C.

the

pin

with the 129th

12th

and

character, the

each

the

of

For

example,

is all 1's the dash

plot

line 75. Refer

(Illustration

B, and

0 at

so that the

to the inputs

IC209A,

are connected

of

of the
IC206

of

selected by

coincidence

ICz08A.

of

plot

coincidence sig-

IC20BA

dots

as a

output of

channel consists

If there are no dot

that shift

IC218C.

8 of

of

the 9-to-15

on

character

so that the

and

8th character

if the
If

value would

Booklet,

C outputs

the top to'1.27

seven

outputs

count

B, and D).

latches

IC207B if the

lC2O2

latches are

inverters,

and IC209.

the Plot

signal is

After a

plot

video

ASCII

the

IC221,8.

out of

The

the

the

the

to

The

of

to

a

dot

line

blanking signal

plot

blanking

blanks the first 128 scan

from the D output of

signal

from

pin

lines.

IC213, or by

IC221.C which

1O of

the

gate,

inputs
information
as logic 1's. This is the composite

a 3-inputNAND

of

(0's)

will appear at the output of

IC222B,and anyvideo

video

lC222B

output.

The

cursor
and IC218B.
the cursor
pear
cursor can be blanked

from the TPU or by a

pin

at

blanked by

12th
pears

The
and IC218A. The

outputs of

proper
signal can be blanked by the
comes from

The

dot, cursor, and

the absence of

video channel consists of

In

absence

the

video signal from

(after

10 of IC201C.

and 1.3th scan

at

plot

delay at the output

proper

the

the

output

pin

video

IC21BB.

5 of

channel

plot

IC206

and IC209 will

the output of lC22LC.

plot

video information.

any

of

delay)

by a

plot

signal,

The

of ICz19B, except during

rows. This blanking signal ap-

consists of

video

video

IC201C,

cursor blanking signals,

pin

2

of

pin

at

6

of

cursor

cursor

signal that appears at the

of

plot

blanking signal

both

of

is also normally

IC201B, ICz08A,

appear after the

IC218A.

blanking

signals are logic 1's in

IC208A,

lC2O2 will ap-

IC21BB.

which appear

This video

signal that

They drive the

The

the

The vertical blanking information
negative logic
signal will be developed
and for the duration of a
the TPU circuit board.

Horizontal
negative logic
signal is developed during the horizontal
and during the three dot spaces between characters.

vertical

The

signals
output

That is, a logic 0 will turn on the electron

CRT.

The
cycle, is
puts

appears as negative

A write

of the master

signal at

blanking information appears as a

signal at the output of

and

drive the inputs of

pulse,

generated

pin

for

horizontal blanking and the

which is used in the screen

lC221,D from the

by

clock divider,lC274.

IC21.7 A. The

3 of

vertical retrace

the

refresh

NAND

logic video information.

appears

interrupt signal from

IC2178.

retrace

gale

lC222A. The

beam in the

A and D out-

as a

blanking

period

This
time

video

erase

The keyboard
encoder, a
cursor control

contains a

special ASCII

latches.

switches.
The ASCII

normally-open
the keyboard
scanned with
pressed,

inputs.

Y

keyboard is

switches that

encoder,.The

a series

one ofthese

After

an appropriate
encoder recognizes
depression,

appropriate
buffer IC403,

output to indicate

the buffer.
keyboard
logic) by

logic for the bus.

true
ration

decodes the X

7-bit

and

The

negative

encoder lC4O2

inverter/buffer

Booklet,

Page

ASCII

puts
that there is

KEYBOARD

52-key ASCII keyboard

character

and twelve mode

a matrix

are scanned

X2 through

pulses.

of

pulses

the

appears at

pulse

and Y

word,

a logic

true logic

is inverted

IC403

The table in Pictorial

shows the

9)

generator,

of single-pole,

XS

When

one ofthe

debounce

as a valid

pulse

data into

latches the

1 on

the data strobe

valid

data

output

positive

fto

provide

to

7-bit

ASCII codes,

and

four

control

IC

by

02,

outputs are

a key is

eight

period,

the

key

the

word in

present

in

of the

true

positive

(Illust-

a-6

CIRCUIT

generated
pear

at the

shows the

these

outputs. When the output enable
brought
and

output enable
IC402
read.

IC401

from

set the rate

A
IC405,
IC406
3-state
line feed
low,

to a logic 0, the 3-state buffers are turned on

the ASCII data is

indicate

to

is a + 1.6 counter

the 60.5 Hz vertical frequency. The

special

and IC406

decodes inputs A1

OFF,

the 3-state

BOARD

by the keyboard encoder, as they will ap-

output of

key

entries that are needed to

line

the

of

character

2)

and ASCII

4J

an ASCII

,

outputs

inverter/buffer IC403. It also

put

on the bus. A logic 0 on the

resets

also

that the data

repeat

generator

is also

the data strobe output of

in

the buffer has been

generates

that

(REPT)

connected to the ASCII

and A2 into four

carriage return, 3) an ASCII

space.

IC404

of

four repeat rates

function.

composed

When both inputs

IC405

and

produce

(OE)

line

frequencies

of IC404,

bus.

states; 1) a

are turned

are

is

off. When A1 is

bus; when A2

when both

These

characters

and during

is high, a

are high, a line
the erase

high, a carriage return

space is

are used in

put

on the bus;

feed is

put

the transmit

cycle.

put

is

on the

and

on the bus.

page

mode

ponding

bered

(vertical

in

latch is

until the next TPU

retrace timeJ,

set

so that

cycle.

Q40L

the data can be remem-

During

the TPU

turns off so that the data

the latches cannot change and confuse the

circuits.

cycle

TPU

lC4O7 and
cursor

Q401

IC408

are latches that are set

control keys.

is turned

on,

During

enabling the cursor

When any of the cursor

The RAM

static RAM,
counter. Twelve
the
characters.
counter can be broken

counter,

During
ICs10B,
IC513,
character line. The
address

scan comes from
generator

address

scan

circuit board) that drives
address.

and

Counter circuit board contains

an address decoder, and

character lines

screen. Each line is composed

Pictorial

See

down into a

+12

and a

scan, the

and IC510C

to access

counter from

circuit board. Also

counter is

row

counter

counter.

+20

counter, IC502,IC5048, IC50S,
cascades into the

a block of B0

count-up

character to

the F

counted up by the D

(1C213

vertical

the

keys is

pressed,

RAM AND

a RAM address

can be displayed

four

of

+-2. The

characters

signal that moves this

pulse

during

the

on

the character

character

blocks

RAM address

+2O

counter, a

+4

character during

the

on

scan, the + 12

output of the

generator

by the four

scan cycle,

controls.

the

corres-

a 1k x 8

on

zo

of

-4

counter,

for

one

character

generator

row

The 1.2 function

keys at the upper
tic are single-pole, single-throw;
switches

logic 1's

erate
mode

to the TPU

pull-up

with

and 0's to convey

circuits.

resistors. These

the

COUNTER

L INE

0
I

2
3

4

5

b

7
8
9

l0
l1

COLUNlN

0123

20

CHAR

COLUNlN

20

CHAR

PICTORIAL 4-7

COLUMN COLUMN

20 C HA R 20 C HA R

right

the Schema-

of

normally-open

switches

proper

gen-

operating

ThethreeRAM

put

a total
quired
IC's

coder that eliminates
dundancies, and

The
memories,
connected in
and the

in
chip
from the I/O

to

512, 526A, 520D,

1k x B memory

write enable inputs

parallel.

select inputs

address

tt

of

bits, which is

address the 1k x 4

decodes the 11 bits

IC507

When

and

parallel.

the write inputs

are

ports

counters

and 5278 form

unused

is made
IC516,
The

low,

of the RAM's.

(+20,

one more than is re-

RAMs,IC507

address codes and re-

up

whose

chip select inputs

(WE)

eight

+4, +12)

and IC516.

an address

down to 10 bits.

two

of

are

also connected

are high

bits

of data is

When the write

10

1k

inputs

and the

out-

de-

x

are

(eSJ

read

inputs are brought low,
into

the
location that is
when the write inputs
inputs
and data
RAM.

4

The
51BJ
location
current location
the RAM
during

are high, the three

can

cursor latches

in

the counter modules

scan, the coincidence

data on the bus can be written

RAM

and latched into

determined by the address inputs

go

high. When

state

neither

where

the cursor is located;

where a character

address counters access RAM locations

read

be

501, 521,D,521C,

[IC's

a specific

ports

I/O

from nor written into the

store the RAM

can be written. As

gates

compare the RAM

memory

the chip select

are turned off

5218, and

address

that is, the

address
and
are exactly
comparators,
IC's
dence,
processed
signal.

ter

cursor line

line
cycle has
ters have
locations.
cursor address
the
sed
written into
was written
RAM
The new
the

The
page
counter, IC's
for

+4

the four
the
fresh period
mation

RAM

counter
of

short form,
the
The
scroll
regardless
As
sequence
specified by

Each
associated
count-down,
that
counter

with the

they will

coincident. These

508, 503,

+4

coincidence,

in the

This

coincidence

generator

on the

of the twelfth

been

accessed,

As

RAM

address

to the cursor

that location
into

address

cursor

cursor address

+4

or start

one of the

scroll counter,

vertical

address

page

start

+20

counter

the

of

determine

+12

and

blocks

blanking period

begins,

is

loaded

is

always

information

the + 12

page

of

address

of whether

scan cycle

through

the

the

counter

with

or the

address

output logic 1's

are

composed

and

520. The three

TPU

circuit

screen. At

completed

the vertical

is loaded

counters.

location

the RAM,

counters

address

scroll

of scan information.

517A,

tz

character

IC506,

L2

of

from

counters.

held

information

counter

because

begins,

the

scroll

modules

it. The

load,

and clear inputs

whether

+1.2

counter. The load

stored in

when the

coincidence gates,

of exclusive NOR

+12

and

generate

to

signal

board

character row,

in sequence,

latches.

5178,

rows

the

is

scroll counter

the mode

RAM,

to

the

and the RAM

blanking

from

the cursor latches

The RAM

and

data can be read

in RAM

the TPU

to the

is then

counters

scroll,

the

In

cleared;

always block

it always

counters.

+20

next

loaded

and

522

rows

stores the

20

of

characters.

ends, and

or start

scroll

long

therefore,

is

always line

module

is long

the RAM

starting

has

module

it

cascades into

the

cursor latches
two addresses

outputs,

a single
is used in
generate

end of the last

all

by the TPU.

contain

of B0

form,

is held

starts

a number

+20

coincidence.

coincidence

the

the

the screen

address

of the active RAM

cycle begins,

is then

will

count up

cursor location.

and latched

the
+12

The

stores the

characters. The

address for

fust

the

screen re-

page

of

counters into

+4

the

the

number

cleared

number

does

not have,a

at character 0

or short form.

address

with the location

and

counters

of controls

has

count-up,

two inputs

input loads

or

gates,

coinci-

are

charac­dashed

scan

refresh

coun-

the

into
addres­from

or

If

data

the

in

start

of

scroll

address

one of

before

infor-

the

scroll

+4

start

0. In
and

0.

+4

the

the

outputs

the

5-bit cursor latch,

input

sets all five
control
+20

counter

+a

the

of

the carry
count-down

+4

The
clear inputs
count-up and
There is

+4)

that

latch

or the

the input
cycle. There is also d

the carry and borrow

input

of the
count-up, load, and clear inputs for the RAM address
counter, and count-up and clear inputs for the scroll
counter.
carry and borrow outputs
up and count-down inputs
counter. There are also three select inputs that deter­mine whether the
with

cursor information, scroll
nary 11. The
made from a + 16

led by IC515A.

reaches

outputs, effectively

In the

count-down

0 to 15,

the binary

and the counter
15, but from 11.

+20

The
end-of-line
is a binary 19 that is decoded
A logic 1 at the output of IC527A indicates that the

+20

counter
end-of-line
IC511D and appears at the output as a logic 0.
three

counter

enable or cursor

+20

the

of

connects

counter.

and borrow

module has

also an input

determines whether the

output of the scroll

of the RAM

There

binary 12,

IC525A immediately loads

11

and the

indicator The

indication is a binary 3 that

counter

bits to logic

the carry

to the count-up

The

inputs

+72

that

has reached its highest address. The

modules share

of the

count-up,
for the RAM
clear inputs for

counter.

is a + 12 --->

RAM

+12

RAM
counter,
When the output of the counter

ICs15A

making it

mode,

generated

is

continues to count

+4

counter modules each contain

load input.

with the

IC501

and borrow

+20

--->

outputs

+1.2

called

address

=4

outputs of the

"select

+12

-->

The

+4

the counter to the count-

of

of

address counter

address counter,

whose modulus is control-

immediately

as the count

+20

by

a common

data

and IC521D.

The

0.

and count-down

+1,2

control

to

the

counter.

count-down, load

address

+4

the

counter will appear

counter during the load

+12

input that

the

a 0-through-11 counter.

by the three select

end-of-line

scroll

scroll

output

input that

+4

module contains

+4

information,

passes

the

down, not

IC525B and IC527A.

contained in

The

clear

+20

outputs

count-up and

counter, and

+4"

the

of

counter to the

connects

RAM address

is loaded

clears

counter with

indication

is

decoded

cursor latch

+4

-->
the

of

inputs

connects

and

counter.

(Sel

cursor

connects

the

a bi-

or

IC519, is

all four

through

lines
from

an

+4

by

All

S

at

TIMING

AND PROCESSING

UNIT

(TPU)

The

timing

ler for

all Terminal

writing,
It
reset
plements

tivities happen

To visualize
to remember that
operation
and
characters are being
RAM and
generator
TPU
TPU
RAM
operated at maximum speed
screen.

As
begins,
keeping

address

screen,
reading,
access

perform
If

data is
can handle
interrupts
tended
serviced,
start
and

TPU
The

B, and

character
applied
trace
cycle
illustrates
ate a series
are labeled

and

generates

routine,

the other

is idle

circuit board. The RAM address

and counter

soon as the vertical

the TPU

chores

counter is

the TPU

writing,

the scroll

scrolling

coming into

TPU

screen

of the next refresh

pick

TIMING

basic TPU

C

outputs of the

Io IC772
period
contains

processing

and

functions.
all data transfers,
an

end-of-line bell

it handles

the transmit page

during the vertical

is

what

within the

is

the

counter circuit board

circuit board. Also,

and there

begins to

within the Terminal.

no longer

can access it

and data

counter

operations

during the vertical

the

screen refresh

cycle. After

refresh

up where

timing

generator

where they

into

eight complete

eight

how

the A, B, and

of non-overlapping pulses.

O thru Z

cursor movements,

going

on in the TPU, it

there are two distinct modes

Terminal.

TPU

cycle. During

displayed on the screen by the

is

little or no logic activity

circuit board is, however, being

retrace period (TPU

transfers. The

and the

the Terminal

the incoming

can

cycle. Then, it

it left

off.

signals

scan row

circuit

sub-cycles.

and each

unit is

perform

the central

It manages

scrolling,

signal, a

function.

to

being

and use

and

retrace
cycle and

start again,

are

board. These

divide

C

outputs and

defines

All

retrace

is the scan

One

the scan cycle,

and the character

during this time,

counter on the

put

characters on the

all of the house-

Since the RAM

used to refresh

the RAM for
TPU

cursor latches

cursor movements.

faster

than the TPU

period,

data has

but only at the

generated

counter,

the

TPU

cycles. Each

Timing Diagram

These

a specific time

control-

the

reading,

and erasing.

power

of these

period.

starts an

will

by

lCZ1,g

signals

vertical

FIr

and im-

is

helpful

cycle

on the

cycle)

can also

TPU

the

been

go

back

the A,
on the

gener-

pulses

up

ac-

the

the

ex-

are

re-

#3

particular

for a
and 7 cycles are
them

with the
IC718C)
(1C215

In general,
tion

operations occur during

Diagram

of

to

operations.
counted up
any

direction, and

The 2

generate

and
the 3 pulse
erase to
of the TPU
to their start

COUNTER
During

always
counter
character
is

always the

is in

the long form

Long Form

During
to

alter the format
the RAM locations.
from.left
single
is

accomplished
cursor starts
both the
zero).

The

+20

(count

right. After

next

C.U.
(00000).

zero
ments
counter then

+4

the

When

+20

C.U.
causes

TPU

operation to

subdivided even further

C

[IC710B

outputs

on the

all reading, writing,

#4.

That is, the RAM

and down, the

pulse

is used

and the

end of line. The 7

operations and

of

CONTROLS

the

screen refresh

cascades into the

is

driven

generator

same regardless

retrace,

to right

line before

at the extreme left

+20

+20

up
the

+20

This

+4

the

accesses

locations.

the

counters

pulse

a carrv

the horizontal

of

character

The 1

the scroll

and

pulse
counter from

pulse

pulse

the scroll

to check for

pulse

6

page positin-

by the

circuit board.
or short

the

counters are

how the

of

In long
through
it moves
by

the

+4

counters

counter is incremented

+20)

signal to move

+20

counter reaches

causes the counter

generates

the 20 locations

reach 19

increments both

from the

occur. The

by ANDing

IC728)

&

generator

is used

cursor

counter

command. The

is used for

pulse

to return

cycle, the + 2 O RAM

character row

form

form,

all 80 RAM locations

down to the

+20

a

0

and B

character

circuit

and

data manipula-

pulse.

the 0
address

can be counted in

scroll coincidence

is

used to wrap

the RAM

+4

counter. The

This

of whether the Terminal

mode.

cascaded

cursor moves

the cursor moves

+4

and

end

cleared

carry

(00)

to

and 3,

counters

+4

counter that

See Timing

for all

counters can be

can be counted.

time between

scroll

counter on the

counter setup

next line. This

counters. The

of the

(each

by the

the

cursor to the

(11001),

19

to count up

pulse

(01).

1

in

block #t of

respectively, the

to zero. This

0, 1,2,

(IC710A

counter

board).

counting

erase and

up all

counters

counter

+12

differently

through

on

line

with

reset

to

C.U.

the

to

incre-

that

-i20

The

incre-

&

a

Pase'8

@

the + 12 counter,

ments
information
Auto Carry

keep the counters

wiII

pulse
then stay at the

A logic 1 from

carry and
cascade into

1C724

pulses

counter. These
ROMs
Form,

+4

EOL.

if the

key

will not

(5707

from
(IC724

Auto

get

borrow

the

pin

the

Carry, Scroll,

Vp' comes
(IC705B

trace.

Short Form
on the keyboard
short form input
in the long
input is
form
Auto
on the keyboard
nal is in the
carry input

Scroll comes from
(lC747A

logic

+20

circuit board
input
counter is

+4

EOL
circuit board
input is
counter is

This addresses

Auto

Carry

is released, and

from

to the + 12

right

pin

2

of

pulses

+4

counter. A logic

10)

+4

counter to

two logic

IC730)

&

pin

form mode.

logic 0, the

mode.

Carry

pin

0 during

EOL

comes from

is logic

19.

comes from the

logic

3.

counter)

end of

IC730

from

causes

signals are

as a function

+20

from the master TPU

a) and it is logic 1 during re-

comes

(S70a

is logic

comes

(5703
auto carry mode
is logic

3). The
a scroll

(5705
1 when

(5707
0 when the

the next

pressed

is

key

line indication

of

end

going

to zero

The

.

the line.

(5706

pin

9) causes the

+20

the

i. from

the carry and

cascade into the

generated

of Vp'

(End

EOL

from

When

Terminal is in

from

pin

0.
the

scroll

the RAM

pin

the

pin

Of

the

Short Form key

pin

10).

1, the Terminal

the short form

the Auto

10). The Termi­when

scroll

command is

operation.

and

a). The

count in the

RAM and

7).

The

count in

line

If

in.

the

(the

carry

cursor will

counter to

pin

2

borrow

+12

in the

Short

,

Line),

and

timing

When the

the short

Carry key

the auto

command

counter

+20

EOL

+20

counter

+4

EOL

+4

the

of

The

signal
selected.

Short Form

of

In

short
through a block of only 20 characters before being
returned

fills
top/start

The
the Auto
entire first block of characters
outputs are zero). When the

(L011),
next
increment the

is

tinues until

A logic 1. from
carry

+

1.2 counter.

8) causes the carry
increment

generated
Carry, Scroll,

"ROM

Identification"
tables

Remember, the cursor
tion where data will be written.
data will enter
short form, data will enter the RAM
columns.
summary

and auto carry signals

EOL

whenever the auto carry

form,

the cursor moves

to the start

block

up a

position

+20

carry

Carry

and the

up

count

all four blocks have been accessed.

pulses

from the

the

as

Programs" section

for ROMs 1C724

Refer

of

position
zqO

of

of the next block of characters.

pulses

key is

+20

pulse

+4

counter to

pin

A logic 1

+4

counter.

a function

+4

section of the

the RAM in 80

to Pictorials

RAM locations

characters, it

increment the

pushed

counter reaches 19

causes

IC730

2 of

+20

from

pulses

of

EOL, und

(444-1.2)

always indicates the RAM loca-

defeat the C.U.

function is not

from

the left to right

the next line. When it

of

+12

in. This accesses the

fwhen

+12

the

(01).

1

(S706

counter to cascade

pin

from the

These logic signals are also

Vp' , Short

+20

(in

character
4-8,4-9,

and cursor

the

counter reaches 11

+12

carry

This

pin

1

1C724

of

+12

EOL. Refer to the

"Semiconductor

the

Manual) for the truth

and IC730

Also, in long form,

in 240 character

+zo

moves

11) causes the

lines,

and

to the

counter if

+4

counter

(11001),

process

counter

Form, Auto

movements.

the

pulse

con-

into the

(S707

pin

(444-17).

while in

+-t0 for a

to

to

ry

Page 59

-

i

I2 ADDRESS

LOCATI ONS
{CHARACTER
ROWS )

i

I2 ADDRFSS

LOCAIIONS
(

CHARACTER

ROWS )

+20

ADDRFSS

LOCATIONS

(

INDIVIDUAL

CHARACTERS

)

0

I
2
3

4

E

6
7

8

9
ll
I

0l

I

ADDRESS LOCATIONS

+4

PICTORIAL

20 ADDRFSS

0

I
2
3

A

5
6
1

8

g

(BLOCKS

4.8

LOCAIIONS

(

2

20

OF

VIDUAL

X I2

CHARACTERS

CHARACTFRS

3

)

)

ADDRESS

I2
LOCATIONS

(

CHARACTIR

ROWS

)

0l

I

ADDRTSS

ADDRFSS

+20

LOCATIONS

(

PICTORIAL

LOCATIONS

BLOCKS OF 20 X

4-9

(

INDIVIDUAT CHARACTERS

23

I2

CHARACTTRS

I

)

0

I

2
3
4

q

6
7
8
I

0

I

ADDRISS

I

LOCAIIONS

(BLOCKS

2

20

x l2 CHARACTERS

OF

3

)

PICTORIAL 4.10

1C724 and
tion
signal.

controls.

During

During

Long Form

Short

+20 + +4

+20

+4 + +12

+12 + +4

short

of

Pictorial

Scan

+20 + +4
+12

Retrace

+20+ +4
+4 + +12

Form

+20 + +12
+12+

+12

+

control

IC730

form,

4-11 shows a summary

the counter

auto carry,

COUNTER CONTROLS

auto

the

carry

button

+

Long Form

Short

.

Short Form

character

is: counted up by

if

auto carry button

if

+4

Scan

Retrace.

Retrace. Long Form. Auto carry
Retrace

modes as

vertical

and

of the

generator

is

depressed.

is

depressed

Form . Auto Carry

a
retrace

counter

board.

func-

pin

7)

that the

so

Terminal is

Next, it checks to see if there was a

up, which occurs if the cursor changes from
or column to another. The Timing Diagrams
that the cursor count-ups
IC735A, B,
the

C.U.

form signal

and D decode the

+72

(57o7

pin

(S704

pin

10). The output

is applied to the D input

++

(1C

(pin

+'1.2

(C.U.

6)

is the

goes

oi

C.U.

clock

high

checks to see if the cursor

with

the scroll or start

+4

and

scroll coincidence signals

and counter

pin

11 respectively).

either one
cycle 1C
output

Next, the TPU
coincident
The
from the RAM
and SZOS
decode the coincidence
form

and apply the
flip-flop IC709B. The
comes

from

the RAM and counter
ing TPU cycle 2C. If
pulse

2C

clocks a logic 0 into flip-flop IC7098,

output

Q

fpin

output to the D

scroll coincidence information

there is scroll coincidence, TPU

8) of the flip-flop

in

the scrolling mode.

+l-2

or

occur only on TPU

+4

C.U.

2)

as functions

(5707

of the short

(IC735D

(pin

2) of flip-flop IC709A. If

+72)

input

to the flip-flop),

islow

(0)

during mf

(r).

page

of

circuit

information.

board

(5702

IC710D and IC733A

signals as a

function

input

circuit board dur-

goes

high.

+4

count

line

one

show

1C.

cycle

pin

9) and

pin

13)

the

address

come

pin

short

of

(pin

12)

and the

When all three conditions have been met, the TPU
knows
column
operation should be

that the cursor was counted away from

the last row

or

on the screen and a

performed.

the last

scroll

Q

is

of

PICTORIAL 4.II

SCROLLING

the screen

When
ters, the cursor

(home)
the

and

screen

(RAM)

can

write new

can be cleaned up and
scrolling operation.
block

of characters

that the

the

or

empty

is

Data
The

screen

give

to
moved

not

the appearance on the screen

around.

row

empty

column appears at
actually moved around
refresh starts at a different

To determine whether a scrolling

TPU checks for three conditions.

occur,

all, the Scroll

the

key must be

has been

return to

This

and

appears at

the

characters

consists of

juggling

pushed in

start of

over

the bottom of

the right of the screen.

filled with charac-

RAM location

the

rearranged

erasing

RAM

within the RAM.

that the

operation

{logic

ones, or

old

with a

a row

or

addresses so

the screen

RAM location

data has

should

First of

0 at 5704

The

outputs of flip-flops IC709A

IC7158.

of
driven from
and D,

key is

(pin
TPU
key is up

low

holds the input
the output
cate that the
is the
the

The

NAND

output of

gate

the

IC7158

IC741B. The

output

Q

which is normally reset

pushed

6) oflCT 418
that a scroll

(released),

(5704

in

goes

low

operation should occur. Ifthe Scroll

the

and sets flip-flop IC733C

(pin

4) to

"hold

Scroll

(pin

scroll

screen" mode. IC733 stays

key

is

lC741B

6) of
operation should take

pushed

and B also stay high for

preset (Q

mally
through

IC739C.

mode, the

(and

the 7C
of IC7158 is high,
output

(h-ofd

circuit board

=

output

Q

pulse).

s- sffeen)

(5702

by TPU

0J

However,

(pin

Therefore,

the

output

of

pin

inputs.

and B are ANDed in

drives

one

other input

8) of flip-flop IC733C

fpin

pin

Z : logic
indicate

to

output

lC741B

in. The

:

(Q

(pin

3)

and D

low,

going

from

Q-outputs

1). If the

0), the output

to the

IC739A

of

(O

which

the duration. They

pulse

7C

that is applied

during the

IC733C

8) of

inhibits IC739

since one input

(pin

6) stays high. The

IC733C is

10)

also sent to the I/O

inhibit

to

external data

(pin

input

(pin

5)

4) is

Scroll

rest

of the

goes

=

1). This
keeps

low
preset

to

place.

IC709A

of

are

indi-

This

until

nor-

hold screen

(pin

a)

Q

The Terminal

pressing

by
or the Erase
either key is
goes

high and the next

IC733C

enabling
flip-flops
flip-flops are then

The scroll command

and applied to one

IC741A. The other

output

The scroll is

transmit

The

input

logic 1

board

scroll counter

Simultaneously,

gatelC722A.

key

Scroll erase is inhibited when the
selected. The
normal

(pin

scroll command

(pin

(on

(S704

is released

either the Scroll

Page key

pressed

D. The 8 output

and

IC739C. This lets the

IC709A

back to their

the transmit

8) of
inhibited when the Terminal

page

mode

1.a)

ffrom

TPU cycle 3),

pin

mode and

ROM

of

pin

3) to the

and changes the start of

it drives one

The other

1).

plot

signal

logic o for

from the hold screen

(S70a pin

key

(5704

pin

Z : logic 1). When

the output

7C

IC709B

and

from

input

(pin

input

:

(0

0).

pin

from

IC724. The ROM

This

input is connected to the

(S70a

(pin

pulse

(pin

7C

(Q

normal states.

IC7418

(pin

RAM

pin

1)

2) is driven

page

flip-flop,

IC741A drives one

3 of

and counter

signal counts

input

pin

1) is logic 1 for the

plot

the

mode

z : logic 1)

1L) of

resets flip-flop

8l

:

of

(pin

mode.

IC739D

goes

high,

pulse preset

All

1).

6 is inverted

NAND

page

plot

three

by the

IC731C.

is in the

outputs

circuit

up the

address.

2) of NAND

mode is

Catg

Q

Plot

Pictorials 4-72

characters.

See
Booklet, Page 10) for a summary of
ation.

ERASING
Erasing the

accomplished in
scroll

erase.

signals from

page

erasing

or

basically the

The write

(S705-8)

the character
spaces on the bus and
RAMs. The
keyboard key ERASE
flip-flop
output
writes
signal
indication. In
stops the RAM

a

form

the + 20
end of
signal comes from
(pin

5) of AND

from the scroll

gatelCT2gB

0

on one
forces
on one
output

erase to end

EOL,

(lC723A)

(pin

13)

to be

lC737D.

of

a space in each location

is

received. lC73O

short form a

counter from counting up. In long

line

end of

line

signal to stop the RAM

pin

gate

IC72

command When both inputs to NAND

are high, the

(pin

input

the

output

(pin

input
(pin

8), which stops the RAM

(pin

9) of

6)

+20).

(Illustration

4-13

and

the scrolling oper-

to the end of line are

manner

same

and

count-up

generator

generate

line

of

circuit board

write

signals

function

[EOL)

S704-12) causes the erase

set on TPU cycle 2 by

The RAM

counts up and

until an end of line

generates

+20

signal

the end

end of

is

ANDed with the

line

counter.

7

IC73O.It

of

The

98.
output

NAND

of

lC737B

of

)

lC722C

drives

one

other input is driven

(pin

6)

gale

places
lC737B.

to logic 0.

causes a

logic

count

as the

(S705-7)

put

for

the

(from

the

line

of

signal

+4

This

EOL

input

logic

a

This

A logic

0 at the

(C.U.

up

0

If

Terminal is not in

the
command
low.
erase cycle.

When the
RAM write signal
character
(pin
special character
S7O4
Simultaneously, through the
pin
space that was on the bus
The RAM

generator
next
RAM. The RAM counter
RAM locations in the same row or block of characters
until spaces have been written
block. During TPU cycle 6 the erase

is

cleared

erase
TPU

start of

occurs,

presets

This

Q

generator

10)

lC737C. This causes lC726A to turn

of

pin

8) which

3),

RAMs

the

count-up signal, coming

circuit board

RAM

location and another space is stored in the

(the

procedure

cycle 3 counted

page

the

flip-flop lC723A,

output

(ngL

(S705

generator

put

are

clear comes fromlC724

stops. While erasing

up the scroll counter to

address to the next line or block of

plot

the

output

A1

(A

write), coming from the
pin

puts

into the write mode and the

(5705

continues

mode and the

(pin

3)

of

which starts the

lC723A

of

B) appears at the

on the

is now

keyboard

a

space on the

output of

stored

from

pin

7)

to access all of the

in

the entire

flip-flop

IC722A

goes

IC737A

in

the

the character

addresses

pin

a)

going

was

move the

scroll

goes

low,

the

output

the

on

(via

A2,

bus.

(S7oo

RAM.

the

row

or

(IC723A)

the

and

on,

During TPU
floplCT23A

Page

Erase

cycle 3,
and the erasing will stop. Whenever the

key

of open collector

(IC723A)

flop
than L

preset.

millisecond
many times while the key is held
page
the
end of

key

cursor

the

presets

at the start

erase.
buffer IC715D
home" input

(pin

pin

4 of IC724 clears

pressed(S7Oa-z),

is

buffer lC715A holds

Erasing

960 characters takes

the output

erase

the erase

so the screen is totally erased

The

position

IC723B,

which automatically

page

of

It does this by

down.

(home)

driving open

and forcing a logic 0 at the

13)

1C728.

of

flip-

(pin

3)

flip-

less

erase

puts

at the

collector

"cursor

CURSOR

RAM

The
how the

and counter circuit description

cursor

moves as a

result

of a writing opera-

describes

tion; however, the cursor can also be moved indepen-

dently of
and through
bus. The

(on

outputs

and
IC727A, B,

writing operations by the cursor controls

some non-writing

cursor controls on

keyboardl

the

enter the

They

-4.

each drive one

C, and

the keyboard set

during the scan

TPU

circuit

D.

When a

coming in on

data

time. The

board at P701-1,

input

of

latch is set, the corres-

NAND

the

latches

latch

-3,

-2,
gates

ponding
next
10,
or 11)

RAM

+2O

A
right,

+1.2
screen
cursor

four

input

pulse

1C

and 1.2

go

to

counter.

count up

a

count down

count up

and

up

the

cursor

of 1C727,

a

movement

board.
Pressing

scroll
counters

the

information,

during TPU
on the RAM
latches

TPU
The

are

actually

cycle 7C.

cursor home
circuit board
causes
ble,
Diagram

a logic

5706-1)

#4.

IC727

of

from

the TPU,

causes

(logic

low

(5706-5)

(S706-6)

(5707-2)

+12

count

screen. TPU

latches

cursor

Home

that

cycle 7,

and counter

latched

signal

drives input

1 output

during

TPU

goes

to

which

the

0). This

moves

moves it

moves

down

cycle

on the

key

was

loaded
into

circuit

by the

(a

logic

pin

13

from pin

cycle

a logic

1. Then

drives

proper

counts

the

output

up

cursor

to the

the cursor

(5706-12)

(5702-3)

3

kevboard

(SZ0

-3)
into

the

cursor latches

board.

trailing

0) from
of

ZC.

ROM

g

(cursor

Refer

the

IC728.

inputs

the

2,

(S,

6,

proper

to

left.

down

moves

resets

circuit

latches

the

RAM

The

cursor

edge

keyboard

This

latch

ena-

to Timing

the

4,

g,

the

A
the
the

all

the

of

defeat signal coming
(lC72O

and
IC730

WRITING

Data is manipulated

logic array
ing from, where it
in, the TPU timing
external

Data flows
in

pin

2 and IC708D

no

auto

pin

6.

carry

signals

DATA/DATA FLOW

within the Terminal

lC702, as a function of

is

devices are ready to accept data.

the bus according to the two

on

Pictorial4-14.

KEYBOARD

All

from the special character

pin

13)

by the end of

or

(EOL.AC)

coming

primarily

where data is com-

going,

pulses,

of the devices

the mode

and whether

o

L

F

=

X

the Terminal is

or not the

diagrams

are tied directlv to

DATA

FLOW

FULL DUPLEX

latch

line

from

by

Since the
information,
the
Timing

scroll

the

upper left

Diagram

information

cursor will

hand

corner

#4 for

the

ships.
Gates IC716A (NAND)and

+L2

count up
generator
the

end

of each characterrow,

the scan row

4,C775

pin
signal appears
is defeated (when
for

the duration

up is

also defeated

mode

and the first

displayed. IC722D

count up

signal
character
counted up by
inhibited

pin

at

[Vn'
+20

counter is

lC722C

(refer

as

to the

controls *ls

+20

counter

signals

circuit

board

counter counts

8).

However,
(Vn'

from

the

of the

when

character

(C.U.

generator.

the output

when the

1.2

vertical

IC722D).

of

counted up by

long

as the

section

+20

on

count

be inhibited

can

coming from

(5705-5).

when
IC705D pin

pin

2

vertical

and

+20,

During

output

scrolling

up for

is also

the

automatically

of the

screen.

cursor timins

IC715C

(AND)

the

During

the D

output
up the
the

+12

vertical

13)the

input

the

line is

lC722C

S7O5-7)

scan the

(pin

blanking

During

IC71OA

to

retrace

time.

Terminal

the

only one that is

control

coming

+20

11

lC7zzD),but

of

signal

the

erase cycle the

is in

the output

a)

lC737B is

fpin

of

and erasing).IC7228

write

operations.

the

+20

by

start

of

appear

Refer

relation,

control

character

scan and

(57

07

counter
blanking
count

is

logic 0)

The

count

the

RAM

the

from

counter is

appears

8)

fpin

count up

page

in
to

the

at

-2)

of

up

plot

the

it is

of

high

The

&

F

=

X

PICTORIAE

DATA FLOW

HALF DUPLEX

4.74

the 8-bit
Ied
and
becomes
keyboard,
data
S701-4)

The
to
and

keyboard
pulse
must

bus

by

turning

off at

the

available

the I/O

available

to

logic

logic

array

determine

counter

circuit

082

during

be ready

and

the appropriate

proper

signal

which

circuit

to
transmit-buffer
the parallel

output

s701-1.2).

The

special
logic
whether
character.

circuit board,
board

character

array lC7O2)

not

or

The

special

and its

as follows:

the

direction

time

in the

from

the

circuit

board

(DAV,

array

IC7O2

then

checks
buffers

board, parallel

board

will

the write

accept

must

be

new

empty

buffer

inputs

are

also

the

character

character

outputs

of data

buffers

TpU

flow

and

cycle.

When

UART, parallel

sends

an

appropriate

at SZ01-3

on

the TpU
a number
and

latches

be turned

cycle.

data,

(XBEU,

must

(pins

checked to

on the bus is

detector

enter

or DAVo*n

circuit

of other

on

I/O,

serial

on

External

that

is,

S701-11)

be

empty

1,2,

B, and 11

is

the TPU

the

determine

is

control-

latches

on

data

input,

board.
inputs

the RAM

I/O,

by TpU

devices

UART

and

(XBEP,

a valid

on the I/O

circuit

or

at

or

to

Carriage Return
Space

Rubout

Control Character
Line Feed
Back

Space

Bell

Control
ten
However, they are always loaded
the
characters
mode, the only control

into the RAM is a carriage
space

for a space

written.

After all input
enables
propriately
clock),
lC7O2.
cial characters are loaded to and from the bus.

characters and

into

the RAM unless the

parallel

at the

output

are

written

cursor

indication before

conditions

the RAM,

pins

at

(load

14

See Pictorial 4-1,5 for a summary of how spe-

rubouts

plot

buffers. In the

into

the

character that can be written

retutn, but

location. Flip-flop

have

parallel,

13

parallel),

and

(ANDed

and 1.7

s701,-7

s702-B

s702-3

s702-2
s701-9
s701-8

s703-1,2

are not

the carriage

settled,

generally

function

into

RAM. In the normal

UART outputs

with the 4800 Baud

(re-select

is chosen.

the UART

plot

mode, all

if

only

there

lC7O4B

return is

TPU cycle 0B2

RAM) of

writ-

and

is a

checks

ap-

CHARACTER
ALL

CONTROL CHARACTERS

*

Except for:

CARRIAGE RETURN

LINE FEED

BACK

SPACE Normal - No

BELL

RUBOUT

NORMAL - No

­Plot - Yes

Normal - Yes
lf

space,

Plot - Yes

Normal - No
Plot - Yes

Plot - Yes

Normal ­Plot - Yes

Normal
Plot

DOES

RAMluARrlour

No

No

-

- Yes

I I

PICTORIAL 4.1,5

CHARACTER

LOAD INTO

Yes

Yes

Yes

Yes Yes

Yes

Yes

_

PARALLEL

Yes

Yes

Yes Normal - Down

Yes Normal

Yes

CURSOR
MOVEMENT

Normal - None
Plot

One space to right

-

Normal - To
Plot

one space to right

-

Plot

One space to right

-

Normal

Plot - one space to right

Plot

Normal - None

Plot

One space to left

-

-None

- One

space to

One space ro right

-

start of

one line

line

right

\
,

Bell
Rings

SPECIAL CURSOR

Whenever the
around on
signal, the TPU assumes that a write operation
been
sor to the

The two
able signals

circuit
low. This
IC719C to

is ANDed with
DAV.

signal
IC722B. The other

goes

goes

If

a control character or rubout was
CC+R output
latched into flip-flop IC720A. The

this flip-flop
through IC7OSD and IC729A. In

cial character was a carriage return, line feed, or back
space, an additional
flip-flops
ANDed with TPU
lC727D)
Ifthe
cleared
is

counted up

+20

the bus in response to a data available

performed

next RAM location.

inputs

(DAV,

board.

1C

(from

low to

low

character is a carriage return, the

counter is counted

If

causes

go

high. This is the internal

if DAV.

IC734

defeat

to count up the

(from

disables the cursor

lC72O

of

perform

to

[S706-7).

(S707-2);

MOVEMENTS

logic

it

and

IC713C monitor the two data avail-

to

and DAVn*a) coming

goes

either

the

output

various

and 0B2

pin

input

the count

pin

signal

and the appropriate Q output is

cycle 1C

the appropriate cursor movement.

If

it was a line feed, the

(IC702)

array

automatically counts the cur-

high,

(pin

TPU cycles

if DAV. The 1C if DAV

drives

6)
(pin

5)
and the

up)

+20

RAM

t8

of the

is latched into

(in

or if it was a back

(5706-6).

down

moves things

from

pin

8

IC713C

of

8) of NAND
DAV

signal that

generate

to

(pin

input

one

is

normally hieh

output

counter.

put

Q

count up

addition,

IC7a0D, lC721C,

the bus, the

on

logic

output

+20

+72

array) is

(pin

(C.U.

if

the spe-

one of the

counter is

counter

space, the

the

goes

0C if

(pin

2)

+20)

has

I/O

gate

)

and

REFRESH INTERRUPT

Normally,

character
ters
IC706B,

screen refresh

whenever
BAUD.

fthrough
the BAUD

rupt
appears
data is
face. This

IC706B.

of
(57O3-7,

high.

IC706B

the Terminal handles

per

vertical retrace

per

second

and IC7188 form

and

data appears

(pin

input

One

the rear

signal coming

pin

at

available from

causes a logic

The

-8,

This

and starts

panel

rate is

greater

from

3 of IC705A

next time

&

of

-9)

clocks the

an

(600

BAUD).

a circuit

starts an

at rates

2)

IC705A

of

BAUD rate

than

I/O

the

and it

the

UART

1. to
that the A",

IC7188 go

logic

artificial

data at a rate

period,

extended TPU

600. The refresh
circuit

goes

or the

appear at the

low,

1 at the D input

vertical retrace

sixty

or

IC705A, IC705D,

that interrupts the

greater

is

tied to a logic

switch)

board

low whenever

parallel

data input

8", and

the

output

of one

charac-

cycle

than 600

whenever

inter-

(S203-3)

inter-

inputs

C"

goes

through

period

(it

6)

through
cycle
within
the cycle by stopping the
screen.
input
blanked by sending a logic
generator
cal cycle continues until flip-flop IC706B is reset
the
character
with
normal TPU
vertical retrace
generator

of

ICTOSD

and the TPU

approximately

The

(pin

"real"

TPU cycle T. After the flip-flop is reset,

(pin

13). This stops the
can service the incoming data

one-half millisecond. It

count ups and blanking the

+12

count up is defeated

2) of lC776A

circuit board

vertical retrace

generator

cycle continues under the

circuit

(S703-1).

circuit board

signal

board.

logic

to a

(Vn')

0

signal

coming

(Vp)

This

from the

TRANSMIT PAGE

During

the transmit
character from the RAM at
and loads it into the

of

fers. In half
empty.

it

and

duplex, it waits for the transmit buffers to

In

full duplex, it waits for the buffers to empty

also waits for the character
When these conditions
the cursor to the next RAM
repeated
When the

until the cursor reaches the end of the

last

character
has been counted up to the start of
TPU

senses

the transmit

off
scrolling

that a scroll

operation.

The Transmit Page
initiates the

lC731D

process

during TPU cycle

page

mode, the

the current cursor

UART and

are

satisfied.

location. This

has

been sent, and the cursor

possibility

page

mode without

button

on

the

by setting flip-flops

7C. TheQ-output

parallel

to be

page position,

keyboard

signals to logic array IC702 that the transmit
mode should begin. On the next TPU 0B2 cycle

pin

comes
from
the
ously,
character has been transmitted. The

0

from

the RAM location addressed by the

parallel

and

it

sets flip-flop IC7O4A to indicate that a

lC704A inhibits
until the cursor has
location. In half
automatically during TPU
the character
device and
happens

duplex,

[The

then counted up. The

whenever

"fake"

a

duplex

button drives the D input

half duplex, a

IC710),

3 of

the logic array

UART output buffers. Simultane-

any further character transmissions

been counted to the next

duplex, the

must be

echoed back from the

cursor

cycle

1C. In full

automatic count

there is a DAV

DAV

signal

logic 1 appears

generated

is

at

D input,

the

screen

by forcing an

0. The screen
to the

artificial

coming

(5703-2)

refresh

stops

character

verti-

by

from

the

ANDed

the

control of the

character

is

TPU reads a

address

output

echoed

TPU

the

buf-

back.

counts

process

is

page.

the

exists, so it turns

performing

the

(S704-9)

IC731C,

(pin

B)

page

(0B2

loads

data

cursor

Q-

into

output of

RAM

is

counted up

duplex,

external

up

signal. For half

byIC725A.

IC725A.)

of

while

In

in

duplex, a logic O appears at the D input. The
pulse (0B2.XP'LOAD)
clocks the

lC725A.

switch is up, which forces

-

indicating
does not occur, so the count up has to wait for
character

Flip-flop lC725A is reset
a function
button. After the flip-flop has been
character will be transmitted
cycle. When the cursor encounters a carriage return
stored in a RAM location,
inhibited
the

same time, the carriage
character latch IC720
IC73SA by the
carriage return flip-flop
referred
0B2.XP.LOAD cycle the Q output addresses
the logic
loaded
character
IC7268,

and Szo+-e)

special character
When the TPU

end of a line and it has not
transmitted a
button is not
further
lC774B monitors

character latch IC720 and the EOL.A-doutput
of RAM IC730.

When both inputs
This means
turn. The logic 1 is clocked into

the 0B2.XP.LOAD
the

foutput

return
IC73BA senses

0B2.XP.LOAD
causes a line

by

the output of
IC721.B
and TPU
flip-flop is
can start again

When the cursor
it

has been

level

at the D input through flip-flop

The

Q-output

"DAV."

be

to

echoed

of the count up signal and

as before, and

0B2.XP.LOAD

to on the Schematic as

array, which

from the RAM. Instead,

the bus via IC7O7B,IC719A,

on

IC726D,

and

of these decoding

carriage

character

end of

(pin

put

to be

feed to be sent. Flip-flop IC738A is reset

goes

low for line feed

cycle 1C

cleared, the character transmission cycle

counted up to

The A1 and A2

generator

senses that the cursor has reached the

pressed,

loads

the FR output

ofIC71.4B are

line.no auto

pulse.

S) of this flip-flop causes a carriage

on the bus by

the carriage

pulse.

NAND

(from

for

the new

reaches

pin

from
(pin

In full

back

by

the

(pin

and the Q output

prevents

return

flip-flop

from the RAM are inhibited.

On

The next

gate

pin

the end of

the

15

the logic array

of

goes

6)

pin

pin

the

+20

return

7) is

on the keyboard.

return

4

line.

low

if the duplex

IC719C

8 of
duplex the

through the UART.

16 of the logic array as

the

cleared, another

the next

on

+20

cursor

counter is cleared. At

output

clocked

pulse.

CRFF. On the next

a

character from being

it

gates

yet

and that the auto carry

IC738B

(pin

high,

carry.no carriage

flip-flop IC738B by

the next

outputs

0B2.XP.LOAD

1C721.8. The output of

(from

oflCT28).

start of

count

from

into flip-flop

This is called the

puts

a line feed

outputs

turn on the

encountered and

6)

pin 6 goes

0B2

A1 and A2.

and is set by the

pin

10 of

As soon as the

page

the

page position,

load

go

to

high

fake DAV

the

duplex

TPU

0B2

up is

special

(pin

5)

pin

9 of

lC726A,

(57O4-4

is set and

special

of

(pin

high.

re-

load

cycle,

pulse

lC72O)

and

after

possibility

scroll
generated.
transmit
at one
The scroll command does, however,
lC725B,
reset the transmit
transmit
TPU 0 cycle.

BELL

IC716B

cursor

when the cursor is in

from the end) of the

information is ANDed in IC716C and IC735C

end of

available keyboard

The

is

IC736,

lC742A for

BAUD rate

lc742A.

The

keyboard. IC742B ANDs
circuit board

also

signal

POWER

When the Terminal is first turned

IC7

17 A

approximately

5)

a

power

a

before

comes on,

R725 and the base

causes

lC7'1.7A. As the

off and the output of lC7'1.7 A drops back to a

R728 applies

speed the transition between logic states. The

positive going pulse

(UART

and holds the

duration of the

page

puts

+4

the

the left hand side

also

page

However, since the Q output

page

input

which,

page

DETECT

and

latch

line

output

which,

approximately 30 milliseconds. The 300

end of

triggers

(or

control G) is detected

UP

generate

reset.

up

power

C719

a logic 1 to appear at the

XR,

lC777E

erase.

the Terminal in the short form mode. This clears

scroll

invert

the

and carriage

exists

flip-flop

(pin

2)

in

mode. lC725B is then reset by the next

IC718A

(P702-7,

signal

(pin

10) of

in

turn, enables

clock then drives the speaker

line

(5703-12)

monostable

the

RESET

200 milliseconds

Capacitor

is

turned on. When the S-volt

begins to charge through

charging current decays,

positive

S702-9).IC777D

erase

200

counter and

of

reset

return

and a scroll command is

(IC731C

IC7a1,A, the

of

lets

turn,

page

decode the outputs of the

-2, -3, -4,

position

(from

signal

IC735C

signal

the

with TPU

a

of

Q701.

feedback to the base of

is

used to

flip-flop, 1C723,

millisecond

inverts the

the

pulse

and IC731D) appears

scroll

preset

next 7C TPU

the

flip-flop, terminating the

and

-s)

number thirteen

20

character block. This

pin

(S702-6),

operates

bell signal from
whenever an ASCII

positive going pulse,

C719

This turns

puts

screen.

and then clear

flip-flops.

IC730), the

9 of

and

triggers monostable

pin

1

of speaker driver

only

cycle 0B2DAV. It

during a write

on,

wide, that

is

totally discharged

output

initialize

inverts

pulse

character block zero at

the

cleared

pulse.

and momentarily

lC717C

(pin

is inhibited.

to determine

TPU

Q701

is

Q701

Q701

the UART

reset

This

andlC717B

the

8) of

flip-flop

cycle

(seven

with

cycle

throush

from

the

cycle.

used

supply

resistor

on and

(pin

2)

turns

logic

Q701

pulse

for the

causes a

transmit

the

+20

the

data

1C.

the
I/O

bell

and

for

of

0.

to

Pase66

(Input/Output)

I/O

@

The I/O
transfers
vices,

See

These circuits contain separate

and output
also contains a serial

{universal

that

serial
rate
start-stop control are
board.

The
through IC620,
normally turned
the Terminal
parallel
causes a logic 1 to
the data
the logic
priority
encoder
to be transmitted
UART
priority,
and the keyboard
lowest priority.

signal by
buffers,IC620.
master
RAM at

When
input
that it
pulse

If
device, it
parallel
transmits
setting
has
is

(input/output)

between the

as a reader/punch

such

Pictorial

interfaces the 8-bit

I/O

generator,

parallel

data available

bus, which

the

data

is finished

on the

the Terminal has

flip-flop IC618B.

finished reading

transmitted

+-t0

ports

and a

asynchronous

ports,

A

special

a data

input

connects to the master

an octal

off. An external

that there is

input

by setting the DAV,

appear at the

priority

1 is

encoder, IC's

permits

the

the cursor location.

will first load

output latches

a

latch. At

clocked through the latch

only one data available

to the TPU

parallel

data available

The TPU

turning

This puts

Terminal

into

the RAM, it

by transmitting

RD,ffi

DAV' signal to the

to

the

circuit

Terminal and all external

(Illustration

input, serial output,

also located on the

611C, 619A, 6198. The

signal

data

on the outputs

allows it to be written into

is finished

output.
data to transmit

the

RTEV6

board handles all

or a digital computer.

parallel

4-bit

receiver/transmitter)

parallel

character detector,

priority

tri-state buffer

parallel

the start

at a

(DAV,)

available

signal

reacts

parallel

the

tells the

that data from the bus into

IC621

When the

data, a negative-going

input.

data

Booklet, Page

parallel

8-bit

handshake.

and a UART
system
latch, and a

device can signal

data

data

to the

writing the

and IC622. It

bus with the

I/O circuit

available at

input to zero. This

input

of the TPU cycle,

and into a

signal

given

has the
IDAV')

(DAVk)

parallel

of the tri-state

input

data on the

external device

a negative

to an external

external device by

external device

11).

input

circuit
a baud

reader

ASCII bus

that is

of IC616,

priority

[DAV)

The

time.

highest
is

next,

has

DAV

parallel

going

then

pulse

de-

It

to

the

the

the

The serial input and
standard
and output signals. The two logic
input
mark is

voltage,

loop. A space is
positive
current loop.
output

Pictorial 4-17
EIA input connections. In its idle state, the EIA
is
biased
is 5 volts, it
UART. When
turns
places
serial output
which, in turn, drives

drives opto-isolator

the

constant

flows from the

Q601
output approximately
of

the

turns
approximately

Refer
for
is
and opto-isolator
logic
When the loop current changes
current),
on.
UART. The reader start/stop
exactly
isolator IC606

mark

a
Q60a

device

TTL.

EIA,

or output are called a

defined as a TTL logic

or 20 milliamperes

voltage,

The

is

defined as a

a negative voltage and it keeps transistor

off. Since

places

the EIA input

on and

a space

from the

photo

transistor in

current source, turns

to the

IC609B

opto-isolator

Q601

to Pictorial

the

applied, loop current

1 then appears at the serial

A logic 0 then appears

is high.

-12-volt

goes

off.

20 mA

current

photo

the

the same manner.

current

wishes to see another character.

output can be

(20

TTY

or

"mark"

defined as a TTL zero, and EIA

or zero current flowing in the 20 mA

idle

state of

mark.

flllustration

the collector

a logic 1 at the input

its

collector

(logic

0) at the

IC604. When the output

*12-volt

low, the LED

turns on the

This

+ 12 volts.

4-18

IC605, which turns

transistor turns off

transistor

and

flowing in the loop, the collector

This tells the TPU that the external

Booklet, Page 72) shows

voltage

UART

IC609B. The output of

IC604 turns

supply through

supply.

-

10 to

causes

(Illustration

loop connections.

passes

at the serial
It is

jumper-wired

mA

current

1, an EIA minus

flowing

both

voltage

voltage

input

(pin

25) drives

Q601

This makes the EIA

*72

volts. As the output

(light

photo

the EIA output

through diode

input to the UART.

to a space

circuitry

composed

Q604.

loop) input

states of a

and

a "space."

in

the current

the input and

transistor

ofthe

(pin

20)

goes

high,

goes

low.

the UART.

of

is a mark,

and

off

The

on.

R631 and

emitting diode)

transistor,

Booklet,

and

As long as there

Page 12)

When

Q603

Q603

input to the

works

IC609A,

Q602,

to

(or

of opto-

for

serial

A

input

Q603

the

of

Q603

This

The

IC609B

a

current

in

which

go

to

a mark

D601

A

off.

zero

turns

in

is

of

Refer to Pictorial 4-19
for

TTL I/O connections. A TTL input signal is

coupled to

IC609C

of the UART. The TTL

from the

input

The
erates a continuous space at the serial
as the break key on the keyboard

line" input at
mark
serial input. This
from

IC602
by

two to

rate

clocks.
IC608A,
generate

pins

drives

to be

either transmitting

successively divides the

IC609D,

output of

labeled

pin

generated

produce

IC601, in

divides the 1200 baud rate

the 110 baud rate clock.

(Illustration

9 and 10 of IC609C. The

which drives the serial input

output signal comes directly

IC609B.

"break"

5 of

at both the serial output and the

effectively

the 2400, 1200, 600, and

at

IC609B

receiving.

or

conjunction with IC607A and

Booklet, Page 13J

pin

2

IC609A

of

output

pressed.

is

causes a continuous

inhibits

4800

baud

clock

One of

the

the baud rate

output of

gen-

as long

The

"off

Terminal

rate

clock

gO0

baud

by 11 to

clocks
"pteset
output and
Baud rate
minal. This
preset
conjunction
clock
or the,baud rate

Integrated

IC624C,

that

certain
rubout
maining IC's

Space,
by
operations.

(600

-

baud

the 300 baud

switch,

switch

baud rate.

with

pulse

inputs

circuits

and

IC624D

monitors

special
and

a control

and

Carriage Return.

the TPU for

9600) can
out" from

the ASCII

characters.

detect

cursor movements

jumper-connected

be

the I/O

rate

SW2,

on the back panel

selects

IC607B,

the keyboard

of the

selected

form

a Back

IC607C,

UART with

by

IC613,

a special

bus to

IC613

character,

circuit board.

output are

either 300

baud

the Baud

IC614,

detect the

and IC61ZA

respectively.

Space, Line

These

connected

and ICGO7D,

rate

key drive

either 110 baud

Rate

IC61,T,

character

outputs are

and

sepcial writing

to

This

of the Ter-

baud

or the

switch.

IC623,

detector

presence

detect a

The re-

Feed,

Bell,

used

the

to

in

the

of

Pase68

@

SEMICONDTJCTOR

This section
Number

is

divided

Index, Part Number
PLA Programs. The first
reference between semiconductor
bers and their

respective

nent numbers are

listed

into

three

parts;

Index,

section

provides

component num-

Part Numbers.

in numerical

Component

ROM

and

The compo-

order. The sec-

IDENTIFICATION

and

a cross-

COMPONENT

This

index

conductor

shows

the Part

in the Terminal.

section

ond
ing

diagram) for

provides

a lead

configuration

each semiconductor Part

detail

Number.

ThePartNumbersinthesecondsectionarealsolisted

innumericalorder.Thethirdsectionprovidesaprog­ram for
tegrated

each of the four specially

circuits.

NUMBER

number

of

INDEX

each semi-

,,programmed',

(bas-

in-

DIODES

ctRcurr

COMPONENT

NUMBER

D1

D2
D101-D104
D105-D109
D11t-D1't2

D301,

D302
D303
D304

D305-D307

D401-D404

HEATH

PART

NUMBER

56-56
56-26

57-42
57-27
57-27
56-56
56-73
57-27
57-64
56-56

ctRcutT

COMPONENT

NUMBER

D401
D402
D501
D501
D601
D602
D603
D604
D605

HEATH

PART

NUMBER

56-26
56-56
56-87
56-87
57-65
56-26
57-65
56-56
57-65

TRANSISTORS

Page

69

clRculr

COMPONENT

NUMBER

INTEGRATED

tc101,

tc202,1c203

tc207,1c208

tc214,1c215

tc404,

tc407,1c408

Q1

Q101

Q102
Q201
Q301
Q302
0303
Q304
Q305

CIRCUITS

1c102
rc103
tc104
rc105
1c201

tc204
tc205
tc206

tc209
tc210
1c211
1c212
tc213

1c216
1c217
tc218
tc219
tc220
tc221
1c222
1c301
1c401
tc402

tc403

1c405

te06

HEATH

PART

NUMBER

417-894
417-899
417-819
417-881
417-864

417-235
417-881
417-864

417-818

442-54

442-609

442-644
442-618
443-745
443-752

443-814
443-812

443-7't9

443-730
443-7't9

443-26
443-730
443-755
443-612

443-81 3
443-838

443-780
443-728
443-755
443-81 3

443-46

443-'t2

442-620

443-838

443-767
443-754
443-8 t 1
443-779

443-728

ctRculT

COMPONENT

NUMBER

Q306
Q307
Q308

Q309
Q401
Q601
Q602

Q604

Q603,

Q701

1c501

tc502
1c503
1c504
tc505
1c506

1c507
rc508
1c509
tcs10

1

lc51
tc512
1c513
tcs14
tcs15
tc516
lcs17

tc518
1c519
rc520
tc52'l
1c522

1c523
1c524
1c525
tc526
1c527
1c528

1c530

rc529,

HEATH

PART

NUMBER

417-81

9
417-818
417-875
417-874
417-801
417-865
417-897
417-801

417-801

443-741
443-817
443-7"t9

443-728
443-745

443-5
443-764
443-719

443-4
443-800
443-745

443-779

443-81 5

443-745

443-81

443-764
443-728

443-781

443-815

443-719
443-781
443-733
443-728
443-797

443-798
443-780
443-779
443-728
443-745

6

Page

70

Integrated

Circuits

CIRCUIT

COMPONENT

NUMBER

1c601,

tc602

rc603

rc604-tc606

rc607
rc608
rc609

tc610
tc611
tc612
rc613
tc614
tc615
tc616
1c617
tc618
rc619
tc620

1c621

,1c622

tc623
tc624

tc701
tc702
tc703
1c704
tc70s
tc706
1c707
tc708
1c709
tc710
lc71 1

(cont'd.)

HEATH

PART

NUMBER

443-733
443-791
443-808
443-745
443-728

443-1
443-779
443-728
443-761
443-732
443-807
443-780
443-752
443-779
443-730
443-797
443-791
443-752
443-807
443-779

4/.3-780
443-787
443-728
443-730
443-779
443-730
443-797
443-779
443-730
443-780
443-728

CIRCUIT

COMPONENT

NUMBER

tc712
tc713
1c714
tc715
tc716
1c717
tc718
tc719
1c720

1c721

,1c722
1c723
1c724

tc725
tc726
tc727
1c728
1c729
tc730

1c731,

tc732
tc733
1c734
tc735
tc736
tc737

tc738

1c739-rc741

1c742

HEATH

PART

NUMBER

443-807

443-800

443-780

443-816

443-797
443-818
443-800

443-728

443-752

443-745

443-730

444-12

443-730
443-728
M3-745

444-10

443-780

444-11
443-728
443-745
443-780
443-779

443-22
443-779
443-730
443-728
443-745

@

U

DIODES

PART

This index shows
diagram)

of each

NUMBER

load

a

semiconductor

configuration

INDEX

detail

Number.

Part

(basing

NOTE: HEATH PART NUMBERS

ARE STAMPED ON MOST DIODES.

.............-

OR

4

OR

aF-,

HOT

SI,

10mA,5V

CARRIER

-,-

OR

#

OR

+:

OR

:1f=-

Page

72

TRANSISTORS

HEATH

PART

NUMBER

417-874
417-875

417-235

,€=f,

c

"4

417-818

417-819

417-881

s44

"NE

B

[fi

-{*'>#[

)g

--4

Page 73

INTEGRATED

442-609

CIRCUITS

s.VOLT

2O-VOLT

REGULATOR

REGULATOR

0ul

OUT

PHASE-LOCKED

OSCILLATOR

LOOP

12-VOLT

REGULATOR

COMMON

CONTROL

OUTPUT

GND

IN

SYNC

SAWTOOTH

.,,4

INPUT

(TOP

ITW}

V

I

I

-L

2

I

3

J

4

tt

DUTY

8

CY CtE

I

R-C

7

I

6

I

PHASE

5

DET.

OUI

":.

lntegrated

Circuits

(cont'd.)

QUADRUPLE

POSITIVE

AND-GATED

FLIP.FLOP

WITH PRESET AND CLEAR

DUAL J.K FLIP-FLOP

2-INPUT

NAND

GATE

J-K MASTER SLAVE

WITH

CLEAR

PRESET

CLOCK

TRIPLE

POSITIVE.NAND

3-INPUT

GATE

Integrated

Circuits

(cont'd.)

HEATH PART

NUMBER

443-22

443-26

MAY BE

REPLACED

WITH

74121

74S00

DESCRIPTION

MONOSTABLE

MULTIVIBRATOR

QUADRUPLE 2-INPUT

POSITIVE.NAND

GATE

IDENTIFICATION

vCC

r,lC NC Cext Cext

NC

IA IB

Rexl/

AI

A2

B

Rint NC

Q GND

443-46

443-612

7402

74193

QUADRUPLE

POSITIVE-NOR

2-INPUT

GATE

SYNCHRONOUS UP/DOWN

DUAL CLOCK COUNTER

BINARY WITH

CLEAR

INPUIS

/ji^ft-kA;\

9AIA ULEAtr

ouTpuTs

vcce66il6iliFfrI?cD

BORROW

CTEAR

COUNT COUNT

oA

DowN uP

DATA 0n 0a

B

*rJ DOWN

INPUT INPUTS

C0UN1

\-----vJ

OUTPUTS

CARRY

COU\I

UP

fo'AD

INPUTS

j-fiATi-f

LOAD

o6

0c On Gl\D

'-ar:

INPUTS

Integrated

Circuits

(cont'd.)

2.INPUT EXCLUSIVE-NOR

QUAD

GATE WITH OPEN.COLLECTOR

OUTPUTS

443-730

OUADRUPLE

POSITIVE-NAND

DUAL

|

74L574

POSITIVE.EDGE

FLIP.FLOP

WITH PRESET

2-INPUT

GATE

D.TYPE

TRIGGERED

AND CLEAR

VCC

I

CLR

CLR

"cc

2

2D zCK 2PR 2Q

ICK

ID

Nc

IPR

IQ

2\ GND

ZO

IQ GNO

8-INPUT

POSITIVE-NAND

GATE

lL<:-*EEtrIr-EtJfl

-

Pase77

Integrated

443-733

443-745

Circuits

741S293

741503

{cont'd.)

DIVIDE-BY.TWO

AND

DIVIDE.BY-EIGHT

4.BIT BINARY COUNTER

OUADRUPLE

POSITIVE-NAND

WITH OPEN

COLLECTOR OUTPUT

2.INPUT
GATE

V66 R6121R

\C R912y

INPUT

INPUlT-r'r---r

) B A

,QA

'QD.

74LS175

74L5240

OUAD-TYPE

COMPLEMENTARY

COMMON

BUFFERS/LINE

OCTAL

INVERTED

DIRECT

LINE

RECEIVERS

3-STATE OUTPUTS

FLIP.FLOP

OUTPUTS

CLEAR

DRIVERS/

CLEAR IQ

Io

ID

20

2Q

2G

GNO

Page

78

Integrated

Circuits

AY-3-1015
TMS6O1
1M6402

(cont'd.)

UNIVERSAL

1 N

RECEIVER/TRANSMITTER

ASYNCHRONOUS

llt40

239
l

4

5

6

1

8)1

1

10
ll
12
t3
l4
r t
16
17

ll ,2

RDA

19

DA

20

S R

NC'NO

INTERNAL

CONNICTION

29
28
27
?6
25
24

22
z\

38
)l

tt
j5

)4

tl

3i

30

3Y GND

4K(1024x4)
STATIC

RAM

A2

d3

GND

Al

U02

|

103

|04

WE

lr=Er:IIririilrer

-

Paoe79

Integrated

Circuits

(cont'd.)

DATA

SIROEE

DATA

STROBE CONTROL

OUTPUT

KIY

BOUNCE

SHIFT

XI

OUTPUT

EMBTE

REPTAT

i\lASK

vcc

CONTROL

LOCK

I

/O

I
2

3
4

5
6
7

8

9
IO
II
T2

4
9b
2
I

B7
B6
B5

Y8
Y7
Y6

Y5
Y4
Y3
\2

YI

Yl0

SHIFT

4/.3-780

QUADRUPLE 2-INPUT

POSITIVE-NOR

QUADRUPLE

POSITIVE.AND

4.BIT

BISTABLE

GATE

2-INPUT

GATE

LATCH

vcc

48

EMBLT

Page

80

Integrated

Circuits

DM8575

74L5244

(cont'd.)

OCTAL

NONINVERTED

BUFFERSILINE DRIVERS/

LINE RECEIVERS

3-STATE OUTPUTS

DATA

INPUTS

GN

IIO
II
Il2
Il3
I1

I4

l!t24

I5

223
322

I6

421

I7

,20

I8

I9

6
7

8

I

9

l0
I I
12

t9
18

It

16

15
ra
ll

I3
I2
II

08
o1

A

03

02

0l

ooro

I

JINPUTS

741520

TRIPLE

POSITIVE-NAND

DUAL

S.INPUT

GATE

4-INPUT

POSITIVE-NAND GATE

vcc

lc

2YI GND

ly

Page

81

Integrated

Circuits

(cont'd.)

TRIPLE 3.INPUT

POSITIVE.NOR

GATE

vcc

0

lc lv

|

2 3 4 5

INPUi5

3c 38

6

7

8 9

3Y

3A

2\ GND

PHOTOTRANSISTOR

OPTO.COUPLER

QUADRUPLE

WITH THREE

BUS

STATE OUTPUTS

BUFFER GATE

[0

.

CATHODF

I

ANODF

NC

2

OUTPUTS

3 4

5

6 | GND

BASE

COtL€CTOR

FMIITIR

Page

82

lntegrated

443-8't2

Circuits (cont'd.)

OUT

04

NC

CND

INH

NC

0l

AZ

03

05

rlt24

2zt
322
421

6

t
8
9
Io
I I

12

14
13

cc

"

(+5V)

NC
A9
A8

A7

tg
tt
ti
to
l5

NC

443-814

4-BIT

SHIFT

REGISTER

0rlrR0(2)

BD

INPUT

RqlllRqr2) N

VCC Rqll)Rcir2)

oJ IPtr Is

QC

QD

QB

INPUTS

OC

C

QD

QA

SER IAL INPIJT

A B

SERIAL A B C D

INPIJT ,-._F_,CoNTROL

c.o(KItsHtfl

R-SHIFT

CKICK

MODE

D

t40DE

clocK;/

(LOAD)

Page

83

Integrated

443-81

5

443-816

Circuits

(cont'd.)

SYNCHRONOUS

DUAL

CLOCK

UP/DOWN

COUNTER

BINARY WITH CLEAR

QUADRUPLE

POSITIVE.AND

WITH OPEN-COLLECTOR

2-INPUT

GATE

OUTPUTS

INPUTS

A

CLEAR

oB o4

0q

0s

DAIA

B

*r- D0WN

INPUT INPUTS

vcc

48 4A 4Y

IP u T

o u

s

BORROII/ CARRY

uP

DowN

COUNI 06

COUNT

UP

\----.VJ

38

/Lom-

LOAD

oc

\----v-

INPUTS

3A 3Y

INPUTS

DfiAi-[rT.

oo

09

443-817

SYNCHRONOUS

DUAL CLOCK

BCD WITH

UP/DOWN

COUNTER

CLEAR

INPUTS

#r;;\

UAIA LLLAX

vcc

r 66iF6fr dTril

0A

DAIA 0e 0a

B

*rJ 00WN

INPUI INPUIS

oJTp.jTs

cOUNT

coTNT

DOWN UP

COUNI

C0UNT

Up

\--'\,_J

OUTPUTS

2Y CND

INPUTS

fo;D D-ftA_i;i-d,

c D

0f 06 6N0

s:-v-:/

INPUIS

lntegrated

Circuits

(cont'd.)

WITH

HEX

OPEN-COLLECTOR

4.BIT

BINARY

INVERTER

OUTPUTS

COUNTER

444-10
444-11

444-12

READ-ONLY

256-BtT

MEMORIES

INPUTR0il)RO(2)

T

AD D AD

DOl

002

D03

D04

NC

D05

VCC

C

AD

D06

NC

B AD

DO8

DO7

NC

A

ry

Paoe8s

-

ROM PROGRAM
444-'t2 IC724

Logic
Term

Input

Pin

#

4z

:<

v>

5>

E

4/

0 0 0 o

o o

0 0

0

o
o

0 o
0

o o

0 7

0

0

o

0 I
0
0

I
L 0
L o
1 o
7

L 0
L o

7

7

L T
I I 0

t L

I
7 L

ADDRESS

F

r

(J

n

t3 L7

0 0

0
0 0
0

T 0

0

t 0

r T

0 1-

0 0

L o

I 0

I

L 0 0

L 0
L 1

L L

0 o

0 0
0
0

0 7

t 0

I

0 7

I 0

0 0

0 1

1 1 O

t_ 0

L I

I

ROM

This
ray)

AND PLA PROGRAMS

section contains a PLA

program

and three ROM

programs.

ff

.t.

.t.

1

I

.t.

.1.

E

10

0

1 0

L 0
7

0

7

0 o o o

0 B

L

L

0

1 1

t

L 0

1 7

0 u

7

L 0

7 t
0 0

t 0
t L
0

0

L

1

0 i. 0 0 1 L

1 I 0 0 T 0

0 1 r o o L

I

L

{Programmed

fRead

Logic

Only Memory)

t?

Logic
Term

Outpul 8 7 o

Pin

# 9

t9

la

,|

Ar-

DATA

a1

r1

|.\

FI

U

5 4

5 4

0

0 T 0 0
0 L

n

0
0 0 L 0 D
0 0 0 0
0 0 u o o

0 0 0 0 0

o I I u 0

0 L 1_ 0 0
0

t L

0 L 1 o o
0 L 0 0 0

I 0 0 o

0
0

1

o

I

L 0

I 0

4

o

0 0 7 0

L
L L
L L 0 0 0
L t 0 7

L L

1

0 0 0 7

o o 0 0

t

7 0 o

L
I I

L 0

ff

TJ

FI

J

N

rl

.t.

ct)

1

N

.t.

.t.

7

a

z

U

r

o o

0 0

0

0 0 D

o o 0

0

0 L

n

0 0

0 7 1

0 0 1

0

7 0

o

7

.t.

1

N

1'

T

1

0

0

0

I

o

r

o

t"n"tu

ROM PROGRAM

444-11 IC730

@

ADDRESS

Logic
Term

Input

PIN

# 1.4 1.3 1.2 LT 1"O Pin

,l

>

1,.\

?e

E

0 0 0 0 o
0 0 0 0

U

0 0 0 L

o

0 0 L !

n

0 0
0 1 0 0
0 7 0 0
0 7 0 7 0
0 7 o
0 t 7 0

u

0 T I
0 T 7

I 0 o o

7 o
7 0 0
1 0 7 o
7 0
7 0 I 7 0 0 0

7 0 I I

7 I o o

1

7 I o

7 I 0

7
7 7 7

1 T I

L t I r

r-l

a't

F

N

.t.

n

c

0 0 7 0

I

0

*l

(-)

z

-t.

D

A

T 0 0 L D 7 0 0 L

7 0 0 7 0 0 0 t L

0 0

r 0

0 I

1 T B

n 0

I t 0 0 0

1 0

t L I l_ 0 I 0 I T 0 0

0 0 7 I 0 I

I

4

T o 7 I 0 o o I

0

L 7 u T 0

T 0
I t 7 0

0 0 o

0 7

t 0
7 I 0 0

0 o o

t 0

U

1 7 0 7 0 T D

L L 0 1 0 7 0 0

D 0 T 0 t 7

I

0

I 0 o t 0

I I 0 I 0 t 0 0

0 L

n

7 1 0 t 0 7 0 0

Logic

Term

Outpul I

# 9

DATA

?

j

IF

7

7 o

il 0 7 0

0 0 1 0 0 0 T I
0 0 0 7 0 u 0

0 0 7 0 7 7 0

Its

t;

t

tr )

:

a')

1'

.t'

t

.1.

4

4

5

7

0

t 0

+

1

1

N

't.

?

a 1

3 I

0 0 7

0 0

u 0

0

7 7

0 1

0 t

0 L I 0

0 0 I 0 I 0 0 I

U

0

0 I 0 L r

1 0 I 7 0

7 0 L 0 t 0 0 u

0 I

0

I 0

0

1

I

t 0 L L

I 0 I

I 0 0 0 0 I

L 0 0 0
T 0 I 0 0

I 0 I 0

0 L

0 0 1 L

0

I
I
I t

0 0 0 L

7

r 0 0 0

u

0 0 0
0 0

0 0

D 0

n

0 I

0 \

0 B

0 0 \

U

0

0 u

lh

U

7

0
0

0

I

I

0

ROM

444-1.0

PROGRAM

1C728

ADDRESS

Logic
Term

lnput D B Output

Pin

#

AE

az

4o

O-

N

U

I4 13 L' LL 10 Pin

Logic
Term

0 0 0 0 0 1 !

o o o 0

r

0 0 0 I 0 0 0 0 0 0 0 L 0

U

0 0 r I 0 L t

o

0 ! 0 o L

0 0 T u

I 0

I L

0 0 I

o

0

n

o

0

7

o o n n
n n n n n n n n n

I 0 L

T

0 0 0 0 0 0 0 L 0

r r

0 0 t

o o o n n n
o n

n n

o L o n o o

7 0 0 0

L 0 0 o

L u 0 o n

0 n n n n n n

t 0 L 0 0

I

a

0

0
t o o

0

o n n n n n n n
n n n n n n

7 L o o 0
L L 0 0

I 7 u

I

7 u

4

L

L

7 0 I 1 7 n I o 0 1

1 I

t L L

t L 0 0 0 7 I 0 7
0 0 o 0 0 o

7

r

0 0

0 0 D 0 0 o 0 o

DATA

N

.t-

1.

a-

E<

a1
J

I

7 6 5

#

9

L 1 7 0 0 0

0 o o o o L I

1 7 T 0 0 0 1 L

0 1 T 0 0 0 L 0

0 o o o 0 L L

n

L 1 1 0 0 O I 1

! o 0 0 o D o

I 0 0 1 7 I 0 7

n n

o 0 0

o o o o o D

0

n n n n o

U

-

-J

'J

o

o 0

U

a)

4

4 7

5

0

0

0

IO

U

N

7

0 1 r

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