Paia 8700 Guide

T.M.

8700

COMPUTER/CONTROLLER

ASSEMBLY

AND

USING

MANUAL.

PAIA

Electronics,

Inc.,

1020 W.

Wilsbire

Blvd.,

Oklahoma

City,

OK 73116

8700

ASSEMBLY

The

PAIA 8700 COMPUTER/CONTROLLER

is

assembled

on

the

double-

sided,

plated

through

...

hole,

etched

circuit

board

provided.

Unlike

other

PAIA

circuit

boards,

this

board

has

all

conductive

traces

pre-tinned

for

easy

solderability

and

does

not

require

scrubbing

before

assembly.

Also unlike many

other

PAIA

circuit

boards,

the

8700

board

is

oomplex;

and on

complex

boards,

unintended conducting

paths

between

conductors

(particularly

where

a

conductor

passes

between pins

on

an

IC)

are

not

unheard

of. While

all

reasonable

quality

control

precautions

have

been

taken,

it

is

a

wise

assembler

who

will

spend

several

minutes

closely

ex-

amining

the

circuit

board

for

these

unintentional

bridges.

Prints

of

the

circuit

board

artwork

have

been

provided

for

this

purpose

in

figures

(1)

and(2).

Bridges

(particularly

on

the

component

side

of

the

board)

will

be

particularly

difficult to find

once

sockets

and

other

components

are

in

place.

Because

of

the

close

proximity

of

some

conductors

to

one

another,

extreme

care

should

be

exercised

during

soldering

to

prevent

unintentional

solder

bridges

during

assembly.

The

likelihood

of

assembly-caused

bridges

has

been

lessened

by

laying

out

the

board

with

an

absolute

minimum

number

of

conductors

passing

between

IC

pins

on

the

soldered

side

of

the

board,

but

care

is

nevertheless

advised.

Use a

clean,

low-wattage

iron

for

soldering

(40

watts

max.).

While

most

temperature-sensitive

components (with

the

exception

of

discrete

tran-

sistors)

are

mounted

in

sockets,

excessive

temperature

can

weaken

or

destroy

the

bond

between

the

conducting

copper

and

the

fibre-glass

board

material.

All

sockets

and

other

components

are

mounted on

the

side

of

the

board

with

the

silk-screened

parts

placement

designators

and

soldered

from

the

opposite

side

ONLY.

00

NOT SOLDER COMPONENTS ON BOTH SIDES

OF

THE BOARD.

NOT

ALL

HOLES

ON

THE cmcuIT BOARD WILL HAVE A PART

ASSOCIATED WITH THEM. Many

of

the

holes

are

conductive

pass-throughs

from

one

side

of

the

board

to

the

other

while

others

are

holes

reserved

for

mounting optional

components.

Some

manufacturers

recommend

filling

through-board

holes

with

solder

to

insure

that

a conductive

path

is

established

from

one

side

of

the

board

to

the

other.

If

you

elect

to do

this,

make

sure

that

you

know which

holes

are

which.

It

is

for

all

practical

purposes

im-

possible

to mount a component

in

a

plated-through

hole

that

has

been

filled

with

solder.

NOT

ALL

PART NUMBERS ARE USED

ON

THIS CffiCUIT BOARD,

some

part

numbers

(

e.

g.

R4)

are

reserved

for

future

expansion.

3

~

:

.......

'-4_•--=

-

-D~__...,

••

·=

=

~~----=·

o-!!-.._

- - - •

-

---

--:----....•

=

-

--=-

-::::.-

-

4

•• •

1

• •

-

--

-

--

-- -

----

---

--

- - --

„ „ „ „ „ „ „

••

•

-

---

---•

•

-

• •

··~~-i

--

·-:tr:~

:

:'\.~-

:J/:

~-------;;-~

- - -

•••••

~==----=

FIGURE

2 -

CIRCUIT

BOARD

FOIL

PATTERN

5

FIGURE

3

8700

COMPUTER/CONTROLLER

PARTS

PLACEMENT

When mounting

components

such

as

resistors,

diodes

and

capacitors,

the

leads

of

the

part

should

be

passed

through

the

mounting

hole

and

then

bent

to a

slight

angle

to

hold

the

part

in

place

for

soldering.

00

NOT

"cinch"

the

leads

directly

against

the

board

(bend

to

a 90° angle).

This

technique

while

great

for

the

government

(and

others

who

are

in

the

habit

of

throwing

away

things

that

don't

work)

provides

only

marginal

additional

mechanical

strength

and

makes

removing

malfunctioning

components

extra-ordinarily

difficult.

AND

REMEMBER.

..

pre-tinned

boards

require

very

little

additional

solder.

With

all

of

these

DOs

and

OON'Ts

out

of

the

way,

we

begin:

HAVE

YOU

INSPECTED THE BOARD?

It

might

just

save

you

a

lot

of

trouble.

U

sing

parts

placement

designators

and

the

parts

placement

drawing

in

figure

3

as

guides,

solder

the

following

resistors

in

place.

Notice

that

many

of

these

r~sistors

are

close

together

and

consequently

may

need

tobe

"stacked"

as

shown to

the

left.

Note

that

resistors

are

non-polarized

components

and

that

either

lead

may

be

placed

in

either

hole

without

affecting

performance.

Installation

of

all

resistors

within

a

given

group

before

any

of

the

resistors

in

the

group

are

soldered

in

place

is

highly

recommended.

ABC

1111,

1 '

Silver

or

gold -

disregard

this

band.

,PART NUMBER(s) VALUE COLOR CODE

A-B-C

(

v5/Rl

-R3 (3

parts).

„

...

3300

ohms.

„ „

„.

orange-orange-red

"#'

/'f.:."

(

'')

1

R5

............................

3300

ohms

........

orange-orange-red

<J

R6

- R 13 (8

parts)

..

„.27K„„

...

„.„

.....

red-v~olet-orange

(

,)

R14 -R21 (8

parts)„

..

27K„„

..„

...

„„

...

red-v1olet-orange

(<YR22

..........................

27K.

................

red-violet-orange

('/) R23 -R25

(3

parts)

....

27K.

................

red-violet-orange

(

")

.;R.26

-R30

(5

parts)„„

lOK.„.„„

.....

„ ..

brown-black-orange

(

jt

1R31 -R37

(7

parts).

„.

lOK„

...

„

........

„

brown-black-orange

(~

) R38 -R45 (8

parts)„

..

lOK„„„.„„„„„brown-black-orange

Install

the

following

ceramic

disk

capacitors.

Like

resistors,

these

components

arenon-polarized

and

either

lead

may

be

installed

in

either

of

the

holes

provided.

;''

(/)

Cl-C7

(7

parts)„„

„ „

.•

05

mfd

disk

(1 C9„..

„„

„.

„„.„

...

„„„„.

05

mfd

disk

V)

Cll,

C12 (2

parts)„.„„.

05

mfd

disk

(V)

C8

............................

33 pfd.

disk

Install

the

Integrated

Circuit

sockets.

Note

that

four

different

socket

sizes

have

been

supplied;

14

pin,

16

pin,

24

pin,

and

28 pin.

00

NOT INSTALL

ANY

OF

THE

INTEGRATED CIRCUITS AT THIS

TIME!

When

installing

the

sockets;

note

that

there

is

a

small

notch

at

one

end,

between

the

rows

of

pins.

This

notch

should

correspond

to

the

notch

on

the

circuit

board

graphics

for

convenient

reference

later

on. 7

8

Install

the

14 pin

sockets

(17

supplied)

in

the

following

locations

Jl

J5

IC5

IClO

IC21

J2

!Cl

IC7

ICll

/

(

\)

J3

( ) IC3

( ) IC8

( ) IC12

( )

J4

IC4

IC9

IC13

Install

the

16 pin

sockets

(9

supplied)

in

the following

locations

( )

.)

'

;·

IC2

IC23

IC31

t

(l,

)

<

(

\~

IC6

IC26

(.

) IC14

( ) IC29 ( ) IC22

( ) IC30

(

!~

Install

the

24

socket

supplied

at

the

location of

IC

19

(

J)

Install

the

28

socket

supplied

at

the

location of IC15

J)

Install

the

3 pin power

connector

at

the

location

indicated

as

J6.

Note that

this

connector

i$ keyed by

the

shape

of

its

base

and

must

be

installed

properly.

(see

figure

on

page

27)

Install

the

8

discrete

transistors.

Note

that

the

transistors

are

keyed

by

the

flat

on

the

side

of

their

cases

and

must

be

installed

properly

for

proper

operation.

Because

of

later

mechanical

assemblies,

it

is

also

important

that

the

transistors

seat

as

closely

as

possible

to

the

board.

The

tops

of

the

transistors

ßhould

be

no

more

than

3/8"

above

the

surface

of

the

board.

. J

( )

QO

)

Q4

(

/>

Ql

(

i)

Q5

(~

)

Q2

(\)

Q6

Q3

Q7

Install

the

three

ln914

diodes

provided.

Like

the

transistors,

these

parts

are

polarized

and

must

be

installed

so

that

the

banded

end of

the

diode

co~responds

to

the

band

indicated

on

the

circuit

board

graphics.

I \

(L

)D3 (

)>n4

V )D5

\

'

Like the

IC's,

the

seven-segment

displays

are

socketed,

but

since

the

pins

on

the

displays

are

not to

standard

tolerances,

Molex

pins

must

be

used

to

mount

these

parts.

The

molex

pins

are

tied

together

at

the

top by a

metal

strip

referred

to

as

a

"carrier",

and to

be

perfectly

correct

the

carrier

should

be

on

the

outside

of

the

two

strips

that

will

constitute

the

socket.

The

molex

pins

are

supplied

in

a continuous

strip

and

must

be

cut

into lengths of 5 pins

each

prior

to

installation

on

the

circuit

board.

Install

and

solder

the

four

rows

of

molex

pins

at

the

IC27 and IC28

locations.

Snap off

the

carrier

strip

after

the

pins

are

soldered

in

place.

We

are

now

ready

to

begin

installing

the

lntegrated

Circuits,

but

first

a

brief

explanation of

where

we're

headed.

The

chances

are

good

that

with

careful

assembly

the

8700

Computer/Controller

will

be

ready

to

operate

when

power

is

first

applied.

Nevertheless,

it

is

a good

idea

to

go

through

the

"power-up"1"

procedure

that

we

will

outline.

The

procedure

entails

the

use

of

an

oscilloscope

and should

be

used

by anyone

with

access

to

one

of

these

devices.

If

you

absolutely

cannot

get

a

scope

to

use,

you

may

skip

this

procedure,

but

for

those

who

can

use

it,

it

will

give

you confidence

in

certain

sections

of

the

computer

and

simplify

trouble-shooting

procedures

in

the

event

that

there

is

a

failure

when

the

unit

is

fully

assembled.

Open

the

integrated

circuit

package

and

install

the

following

integrated

circuits

in

their

respective

sockets.

Notice

that

the

orientation

of

the

ICs

is

keyed

by

a

semi-circular

notch

at

one

end

of

the

device,

and

that

the

position of

this

notch

should

correspond

with

the

notch

that

is

part

of

the

circuit

board

graphics.

WARNING CMOS cmcurrs

Some of

the

integrated

circuits

used

in

this

kit

are

Complementary

Metallic

Oxide

Semiconductors

(CMOS). While

state

of

the

art

internal

protection

is

provided,

these

circuits

are

still

susceptible

to

damage

from

STATIC ELECTRICITY. You should

not

experience

any

difficulties

if

you

observe

the

following

precautions.

1)

The

circuits

are

supplied

to

you

inserted

in

blocks

of

conductive

foam.

Leave

them

in

these

blocks

until

you

are

ready

to

install

the

part

•.

2)

Do

not

install

the

parts

in

sequence

other

than

that

called

for

in

the

instructions.

3)

Do

not

wear

synthetic

(

e.

g.

nylon) clothing while handling

these

parts.

Inst

all

the

following

IC

s

in

their

sockets.

NOTE: FND 357

displays

are

k~.yed

by

a

series

of

small

grooves

on

their

top edge•

.

,.

( l

ICl

74LSOO

(i

) IC2 4042

()

IC3

~

JIC4 4001 ( ) IC5 4011 ( ) IC6

IC7 4001 ( ) IC8 4001 ( ) IC9

:l

IClO 74LS02 ( )

ICll

4001 ( ) IC12

IC13 4011 ( ) IC14 4556 ( ) IC15

~···

~

IC21 4001 ( ) IC26 9368 ( ) IC29

IC27 FND 357 Display ) IC28 FND 357

4001

4042

4011

6503

9368

This

should

leave

you

with

5

ICs

that

have

not

been

installed;

four

2112 RAMs and one

170'/A PIEBUG

monitor

PROM.

(A U

sing

a

section

of

resistor

clipping,

form

and

install

the

jumper

indicated

as

S2

on

the

parts

placement

diagram.

Leave

a

generous

loop

in

this

jumper

as

it

will

be

cut

open

later.

9

10

The

jumper

that

was

installed

above

enables

a

test

feature

of

the

8700,

described

in

the

"Self

Test"

section

of

this

manual,

you should

at

this

point ski.p to

that

section

and

perform

the

tests

outlined

there.

Return

to

tllis

point

for

final

assembly

when

the

procedure

outlined

has

been

·com.pleted.

v{/

Clip

the

jumper

:i.nstalled

as

S2

in

a

into two

sections

and

spread

the

sections

apart

so

they do

not

touch, but so

that

they

may

be

re-soldered

if

needed.

<j(

Using a section

of

excess

resistor

lead,

form

and

install

the

jumper

indicated

as

Sl

on

the

circuit

board

graphics.

(This

jumper

enables

"normal"

operation

of

the

system,

and

~

be

in

place

for

the

unit to function

properly.

·

c6

In.stall

the

rema:i.ning

Integrated

Circuits

in

their

respective

soc~ets

(observe

. . • 1

orientation

markings).

i

d)

IC22

(~)

IC31 2112

2112

/

<(>

( ) IC23

IC19 2112

1702A PROM

{

<\t

IC30 2112

This

completes

assembly

of

the

8700 CPU

board.

Proceed

to

assembly

of

the

8700A

active

keyboard.

·

87

00

/A KEYBOARD ASSEMBLY

Prepare

for

asseinbly

by

thoroughly

cleaning

the

exposed

copper

circuitry

above

colored

keyboard

area.

U

se

steel

wool

and/

or

scouring

cleanser.

00

NOT

USE

PRE-SOAPED

STEEL

WOOL

PAD.

Use

particular

care

to

avoid

scratching

the

printed

keyboard

area.

Rinse

and

dry

the

board

completely

before

beginning

assembly.

A

WORD

OF

ADVICE:

-

Do

not

clean

th~

circuit

board

until

you

are

ready

to

assemble

and

test

this

unit. When

assembly

is

complete

and

the

unit

verified

as

being

operational,

a

coat

of

artist

1

~

spray

fixative (

available

at

most

artist

1

s/

,

engineers

supply

stores;

e. g.

11

Blair

Spray

Fix'')

will

keep

the

copper

bright

and

shiny and

prevent

oxidation.

DO

NOT

try

to

protect

the

copper

with any

oil-based

sprays

as

these

may

entrain

moisture

or

otherwise

become

conductive;

NOTE

that

there

are

no

sockets

used

in

the

8700/

A.

And finally,

just

so

there

is

no confusion,

the

parts

are

mounted

on

the

side

of

the

board

marked

"ICl",

11

Rl

11

9

etc.

·

ABC

l_l

l_l,

__

I ,

Silver

or

gold

-

disregard

this

band.

Begin

assembly

by

soldering

all

resistors

in

place

as

per

the

parts

placement

designators

printed

on

the

circuit

board

and

the

detail

figure

4.

Figure

4

DESIGNATION VALUE COLOR CODE

A-B-C

(})

Rl

-R16 (16

resistors)

.........

82K

....................

grey-red-orange

( )

Rl

7 - R20 ( 4

resistors)

.........

lOOK

.....................

brown-black-yellow

( ) R21 -R24 ( 4

res~stors)

.........

150K

.....................

bro~-green-yellow

( ) R25-R48 (24

res1stors)

.........

27K

.......................

red-v1olet-orange

T~~re

are

13

solid

wire

jumpers

used

on

this

board.

for7/a'.nd

install

these

jumpers.

(

~··

Form

and

install

13

jumpers.

Count

them.

(1

Locate

the

RESET

push-button

(Sl

) and

prepare

it

for

installation

by

using

a

pair

of

needle-nose

pliers,

to

carefully

bend

its

two

solder

lugs

out

to

90°

angles

as

/

1·

shown

in

detail

figure

5.

( )

Cut

the

length

of

insulated

wire

provided

into two

equal

5-inch

lengths,

strip

1/4

inch

of

insulation

from

each

end

of

each

wire

and

twist

and

tin

the

exposed

ends.

Solder

one

end

of

each

of

the

lengths

to

the

lugs

of

the

switch.

U

sing

the

solid

wire

provided,

SOLDER

TWO

LENGTHS

OF

INSULA

TED

WIRE

Figure

5

11

12

1

:t

i

Using

the

hardware

supplied, mount

the

RES~T

button

in

the

circular

hole

directly

above

the

rectangular

display

cut-out. NOTE

that

the

pushbutton

m.ounts

from

the

component

side

of

the

board

so

that

the

actuating

stud

protrudes

from

the

side

of

the

board

printed

with

the

keyboard

designations.·

Solder

one

of

the

two

wires

connected

to

the

RESET button

to

the

circuit

board

point

labeled

"A"

and

the

other

to

the

circuit

board

point

labeled

"B".

Install

the

14

lead,

DIP

header

terminated

I/O

connector

as

follows:

(f)

From

the

component

side

of

the

board,

push

the

14

pins

of

the

keyboard

I/O

cable

header

(

either

end

may

be

used)

into

the

14

holes

provided

at

the

circuit

board

location

marked

"I/0". While

either

end

of

the

jumper

may

be

used

here,

the

header

MUST

be

installed

so

that

the

wires

coming

from

it

point TOWARDS THE NEAREST EDGE

OF

THE CffiCUIT BOARD

as

shown

in

detail

figure

6.

(

\)

Carefully

solder

all

14

pins

of

the

header

in

place.

Excessive

heat

at

this

operation

can

melt

the

header.

Make

sure

that

the

copper

is

very

clean

before

soldering.

INSTALL

DIP

HEADER

50

THAT

WIRES

COME

FROM

SIDE

CIRCUIT

BOARD

EDGE

WARNING

CMOS

CIRCUITS:

Observe

cautions

previously

outline •

Figure

6

A

three-wire

grounded

soldering

iron

is

ideal

but

if

you

don't

have

one,

your

present

iron

may

be

used

by allowing

it

to

heat,

then

UNPLUGGING

it

during

the

soldering

operation.

Before

soldering

and

after

unplugging

touch

the

tip

of

the

iron

momentarily

to

the

ground

screw

of

an

electrical

outlet

or

other

source

of

ground

to

drain

the

static

charges.

Install

the

six

4001 CMOS

NOR

gate

packages

IC-1

through IC-6.

t~~~~~~-6

............

~:::lB

.

THIS COMPLETES ASSEMBLY

OF

THE PAIA

8700/

A KEYBOARD.

FINAL ASSEMBLY-

/'.

Using

the

hardware

illustrated,

mount

the

8700A

active

keyboard

above

the

8700

CPU

board.

Note

that

two

5/16"

spacers

are

used

on

each

of

the

1"

machine

screws

that

hold

the

keyboard

above

the

processor,

and

that

the

displays

are

visible

through

the

rectangular

cut-out

above

the

RESET·

switch.

ALSO

check

that

the

solder

lugs

on

the

RESET

switch

(S3 on

the

8700A)

do

not

contact

any

of

the

components

on

the

CPU

board.

If

necessary,

loosen

the

switcb

and

re-orient.

Uusing

the

hardware

illustrated,

mount

the

two

remaining

rubber

feet

at

the

rear

edge

of

the

8700

board.

(

~l\fate

the

14

header

of

the

keyboard

I/O

cable

with

the

14

socket

J3

(the

middle

socket

of

the

five

along

the

rear

edge

of

the

CPU

board).

4-40X

(-4

PLACES

,„

4-

40

X

"'4

- 2 PLACES

Figure

7

S_...1

6" SPACER-8

PLACES

RUBBER

FEET-

6 PLACES

4-40NUTS-6

PLACES

THIS

COMPLETES

ASSEMBLY

OF

THE PAIA 8700

COMPUTER/CONTROLLER.

Check

out

the

system

using

the

Testing

and

Preliminary

Familiarization

section

which

follows.

13

;>,,

',

NOTES

14

TESTING &

FAMILIARIZATION

THE

PAiA

MONITOR

(PIEBUGl

Now

that

you

have

your

computer

assembled

the

is

obviously to

try

it

out.

To

do

that

you

will

have to know a

little

bit

about

the

monitor

program.

We

will

assume

that

you know

little

or

nothing about

computers

and

attempt

to explain why

there

is

a

monitor

program

in

the

first

place.

You

can

think of

your

computer

as

a

machine

that

follows

your

instructions

to

the

letter.

That's

really

all

that

any

computer

is.

The

group

of

instructions

you give

it

to do a

specific

job

is

called

a

program.

A

person

that

writes

a

set

of

instructions

(program)

for

a

computer

is

commonly

called

a

"computer

programmer".

There

are

lots

of

computers

in

the

world,

consequently

there

are

lots

of

computer

programmers.

You

are

about to

become

one!

In

general,

a

computer

by

itself

is

useless.

There

is

no way to feed

instructions

into

it

or

get

results

out of

it.

Although

it

has

the

ability

to follow

your

directions

it

must

rely

on

external

equipment

or

devices

for

input and output

operations.

The

external

equipment and

devices

fall

into a

category

known

as

"peripherals"

and include

such

things

as

printers,

CRT

terminals,

teletype

terminals,

tape

drives,

card

readers,

and

so

on.

On

small

computers

you may find

peripherals

such

as

cassette

recorders,

A/D

and

D/

A

converters,

relays

to

control

external

events,

etc.

The

PAIA 8700

Computer/Controller

has

two

peripherals

that

come

with

it;

a keyboard and

display.

The

keyboard

has

24

"touch-pad"

keys.

Each

key

is

activated

by

simply

touching

it

with

your

finger,

there

is

no

key

movement.

If

you

have

the

CS-87

Cassette

option

each

keystroke

is

accompanied

by

the

muted

"beep"

of

the

audible

feed-back

circuitry.

Eight

of

the

keys

are

for

control

functions

while

the

other

sixteen

represent

the

hexadecimal

number

set.

Hexadecimal

is

a

number

set

that

fits

computers

very

well

but

contains

sixteen

symbols

instead

of

ten

like

you

are

used

to working

with

now.

The

symbols

used

in

the

hex

(short

for

hexadecimal)

set

are

O

through

9 and A

through

F (

i.

e.

, O

12

34 56 7 89

AB

CD E

F).

If

you

don't

know

hex

it

will

be

fairly

easy

for

you to

learn

since

you

are

already

familiar

with

all

the

symbols.

Obviously

the

purpose

of the

keyboard/display

is

to

get

programs

and

infor-

mation

into and out of

your

PAIA

computer.

However, to do

this

task

the

computer

must

have the

instructions

(program)

to

tell

it

how to

perform.

That

is

the

purpose

of

the

monitor

program.

It

instructs

the

computer

on how to

interpret

the

information

from

the

keyboard

and what

information

is

to

be

sent

to

the

display.

The

basic

use

of

the

monitor

is

in

loading and examining the

contents

of

memory

using

the

keyboard

and disp1ay.

That

gives

you the ability to

enter

a

program

into

the

computer

from

the

keyboard,

try

it

out,

and change

it

if

necessary

.•

The

Monitor

will

perform

other

functions to

aid

you

in

your

feat

of using the

computer

and

those

functions

will

be

explained

as

you

read

on.

15

ENTERING

A

PROGRAM.INTO

THE

COMPQTER

' .

-·

The

following

is

a

sample

program

that

we

will

use

as

an

example:

ADDR CODE LABEL INSTRUCTION COMMENTS

0000 A9 00 BEGIN LDA

#0

;CLEAR ACCUMULATOR

0002

BD

20 08

REPEAT

STA $0820 ;DISPLAY ACC

0005

AO

00 LDY #0

;CLRY

0007 A2 50 LDX #$50 ;SPEED SETTING (IN HEX)

0009 es LOOP INY ;DELAY LOOP

OOOA

DOFD

BNE LOOP ;BRANCH UNTIL

Y=O

oooc

CA DEX ;CHECK

SPEED

OOOD

DQ

FA BNE LOOP ;BRANCH UNTIL

X=O

OOOF

F8

SED ;SET DECIMAL

MODE

0010 18 CLC ;CLR CARRY

0011 69

01

ADC

#1

;ADD

1 TO ACC

0013 4C 02 00

JMP

REPEAT

;00

IT

ALL

AGAIN

Fig

1.

This

program

will

make

your

computer

count

from

O

to

99 and

then

start

over.

You

will

be

able

to

see

it

count

by

watching

the

display.

You

will

notice

that

the

format

of

this

program

listing

is

divided into

five

"fields";

ADDR, CODE, LABEL, INSTRUCTION and COMMENT.

Each

of

these

fields

has

its

own

significance.

The

ADDR

column

is

the

"address"

in

memory

(more

on

this

shortly)

of

the

data

or

instruction.

The

CODE

column

is

the

actual

"machine

language"

which

will

be

stored

at

the

memory

location

specified

by

the

ADDR

field.

The

first

two

digits

of

the

CODE

field

are

referred

to

as

the

OP-CODE,

this

is

the

part

of

the

code

field

that

tells

the

computer

which

instruction~

among

its

repertoire

of

many

dozen,

it

is

to

execute.

The

pairs

of

digits

following

the

op-code

are

called

the

OPERAND and

in

general

this

part

of

the

CODE

field

tells

the

computer

where

and how to

execute

the

instruc-

tion

specified

by

the

op-code.

Notice

that

some

op-codes

have

one

pair

of

digits

for

the

operand

while

others

have

two

pair

or

none

at

all.

In

general,

a.

computer

executes

instructions

in

a

linear

manner;

doing

one,

then

the

line,

then

the

etc;

but,

there

will

be

times

when a

program

will

"loop";

that

is,

repeat

a given

section

of

the

program

a

number

of

times

to

obtain

the

required

result.

For

the

convenience

of

the

programmer

(this

is

!!2.t

entered

into

the

macbine)

the

LABEL

field

is

provided

for

naming

specific

locations

or

parts

of

the

program

that

are

to

be

"jumped"

to

out

of

their

normal

sequence.

For

example,

the

last

instruction

in

our

demo

program

is

JuMP

REPEAT,

which

mea.n.s

that

when

the

computer

executes

this

instruction

it

will

jump

back

to

the

portion

of

the

program

marked

as

REPEAT

in

the

label

field

(in

this

case,

at

location

0002) and continue

running

the

program

from

that

point on.

The

INSTRUCTION

field,

like

the

LABEL

field

is

provided

as

an

assistance

16

to

the

programmer.

lt

is

difficult

(at

least)

to

remember

all

of

the

op-codes

in

the

computer'

s

repertoire,

and

the

INSTRUCTlON

field

provides

space

for

a

mnemonic

(pronounced

ne

1

-mon-ic

- a

memory

aid)

for

the

instruction

that

the

computer

is

to

execute.

Some

programmers

may

be

able

to

look

at

the

op-code

A9

and

remember

that

it

is

the

instruction

for

loading

the

accumulator

in

the

immed-

iate

mode,

but

LDA #0 (LoaD

Accumulator;

#,

an

almest

universal

symbol

for

"immediate";

and

O,

the

thing

tobe

entered

in

the

accumulator)

is

a whole

lot

easier

to

remember.

The

COMMENT

field

is

another

aid

to

the

programmer.

In

this

area

is

written

a

short

comment

on

the

reason

for

using

that

instruction.

ldeally,

the

scope

of

the

comments

used

should

be

sufficient

for

a

person

other

than

the

programmer

to

make

out

what

it

is

that

the

program

is

doing

(this

rarely

happens

in

practice).

As

you

may

have

concluded,

the

ADDR

and

CODE

fields

are

the

only

ones

that

have

anything

to

do

with

the

numbers

that

you

enter

into

the

computer

to

make

the

program

run.

At

this

point

it

becomes

necessary

to

define

a

"byte".

As

we

mentioned

above,

some

of

the

instructions

consist

of

two

digits,

some

four,

and

some

six,

but

all

of

them

were

in

two-digit

clusters.

Each

cluster

is

called

a

''byte"

and

that

is

the

main

unit

of

measurement

we

will

be

working

with.

For

example:

instead

of

saying

each

instruction

can

consist

of

two,

four,

or

six

digits,

we

say

that

it

consists

of

one,

two,

or

three

bytes.

The

memory

of

your

computer

is

also

measured

in

bytes.

lt

comes

with

512

bytes

and

an

additional

512

bytes

can

be

added by

simply

plugging

in

four

more

memory

lC

's.

lt

takes

three

bytes

of

memory

to

store

(hold) a

three-byte-instruction.

Each

byte

of

mem-

ory

has

a unique

address

associated

with

it

which

enables

the

computer

to

pick

out

the

particular

byte

it's

looking

for.

You

can

easily

visualize

how

the

computer's

memory

is

organized

if

you

think

of

it

as

a town

with

only one

very

long

street.

All

the

houses

of

the

town

are

on

that

one

street

and

the

only way

you

can

locate

a

particular

house

is

by

its

address.

If

you

think

of

each

house

as

representing

one

byte

of

memory

then

that's

what

your

computer's

memory

looks

like.

Each

unique

address

is

specified

using

a

four-

digit

hex

number.

Look

under

the

"ADDR"

column

of

the

program

listing

(Fig.

1)

for

µn.

example

of

this.

Notice

that

some

numbers

are

skipped

in

the

column.

Each

address

shown

is

the

address

of

the

first

byte

of

the

instruction

on

the

same

line.

In

the

case

of

a

two-

or

three-byte

instruction

the

addresses

of

the

additional

bytes

are

not

shown

but

they

are

counted.

Count

the

bytes

in

the

program

and

you

will

notice

that

each

time

you

start

on

a new

line,

the

count

will

agree

with

the

address

listed

on

that

line

until

you

get

past

nine.

Remember

now

that

we

are

working

in

hexadecimal

(hex)

and

there

are

six

more

symbols

to

count

after

the

"9"

symbol.

Here

is

an

example

of

how to

count

in

hex:

0,1,2,3,4,5,6,7,8,9,A,B,C,D,E~F,10,ll,

12,13,14,15,16,17,18,19,

lA,

lB,

lC,

lD,

lE,

lF,

20~21,

...••....•....

97,98,99,9A,9B,9C,

9D,9E,

9F,

AO,Al,A2,

..•..••

A8,A9,AA,AB,AC,AD,AE,AF,

BO,

Bl,

B2,

.......•

F8,

F9,.FA,FB,

FC,

FD,

FE,

FF,

100, 101, 102,

..••.•...•

and

so

on.

17

\

Now

you should

be

ready

to

enter

the

program

from

Fig.

1 into

yourcomputer.

·.Start by applying

power

tO

the

computer

•

then

press

the

reset

button.

Arbitrarily

touch

some

of

the

numbered

keys

and

notice

how

the

.numbers

shift

left

through

the

display.

The

display

only shows

the

last

two

entries

from

the

keyboard

but

the

computer

can

remember

as

many

as

the

last

twelve.

If

anything

goes

wrong and

the

display

stops

responding

to

the

keyboard,

press

the

reset

button

and

it

should

return

to

normal;

. 18

Now

type:

0-0-0-0

DISPLAYshows: 00

(Touch

the

Okey

four

times)

DISPLAY

xx

<x-don't know,

don't

care)

(Touch

the

DISP key)

Tbis

sets

the

pointer

to

memory

location 0000, which

is

the

address

of

the

first

byte

to

be

entered

into

the

memory

(see

ADDR column

of

Fig.

1.

).

The

display

will

show

the

contents

of

that

location.

This

operation

lets

the

monitor

know

where

in

memory

your

program

is

tobe

stored

(programs

don't

always

start

at

0000).

Type:

A-9

ENTER

DISPLAY shows:

A9

XX

Tbis

ente:rs

the

first

byte

of

the

program

into

the

computer's

memory,

moves

the

pointer

to

the

nex.t

address

in

memory

and

displays

the

contents

of

that

lt

is

important

to

understand

the

concept

of

the

pointer

since

it

will

be

referred

to

quite

often.

Each

time

the

"ENTER"

key

is

touched1 what you

see

in

the

display

will

be

stored

in

the

memory

location

specified

by

the

pointer.

The

pointer

will

then

be

increment-

ed

to

the

nex.t

memory

location and

the

contents

of

that

location

will

be

displayed.

Type:

0-0

ENTER DISPLAY shows: 00

XX

This

enters

the

second

byte

of

the

progra.m into

memory.

The

first

and

second

bytes

of

the

program

form

the

first

instruction

of

the

program

which

is

a LDA

(load

accumulator)

instruction

(See

Fig.

1).

Type:

8-D

ENTER

2-0

ENTER

0-8

ENTER

DISPLAYshows:

8D

XX

20

XX

08

XX

These

three

bytes

form

the

second

instruction

(STA-store

accumulator)

of

the

program

(See

Fig.

1).

Now

that

you

have

the

hang

of

it,

enter

the

rest

of

the

program

listing

under

the

"CODE"

column

in

Fig.

1

starting

with

AO,

00, A2,

etc

•

CORRECTING

ERRORS

lf

you

make

a

mistake

in

typing

but

catch

it

before

touching

the

"ENTER"

key

then

you

can

correct

it

by

simply

retyping

the

correct

entry;

the

mistake

will

be

shifted

out

of

the

display.

If

you

have

already

entered

the

mistake

in

memory;

then

touch

the

"BACKSPACE"

key

and

the

mistake

will

reappear

in

the

display.

Now

type

the

correct

entry

and

then

be

sure

to

touch

the

11

ENTER"

key

or

the

memory

will

still

contain

the

mistake.

Touching

the

"BACKSPACE"

causes

the

mon.itor to

decrement

the

pointer

and

then

display

that

location.

EXAMINING

THE

PROGRAM

Now

that

you

have

the

program

in

memory

it's

a good

idea

to go

back

and

cneck

it

to

make

sure

it

was

entered

100%

correctly.

If

even

one

digit

is

wrong

then

the

program

will

not

operate

properly.

First

you

must

let

the

monitor

know

where

in

memory

your

program

is;

or

in

more

technical

terms:

set

the

pointer

to

the

beginning

of

the

program.

To

do

that

you

must

type:

"0-0-0-0-DISPLAY".

Always

remember

that

the

"DISPLAY"

key

is

used

to

set

the

pointer.

The

display

should

now show

the

first

byte

of

the

program

(A9).

If

it

doesn't

then

you

have

done

something

wrong

and

you

should

start

all

over.

If

it

does

then

you

can

examine

the

by

simply

touching

the

"ENTER"

key.

This

causes

the

data

shown

in

the

display

(which

is

what

was

in

the

memory

location

in

the

first

place)

tobe

entered

back

into

the

same

memory

location

and

increments

the

pointer

to

display

the

You

can

step

through

the

program

by

repeatedly

touching

the

"ENTER"

key.

The

series

of

bytes

seen

in

the

display

should

correspond

with

the

ones

in

the

program

("CODE"

column

of

Fig.

1).

lf

you

find a

byte

that's

not

correct

you

should

retype

it

while

it's

in

the

display

and

then

touch

the

"ENTER"

key.

RUNNING

THE

PROGRAM

Everything

should

be

set

to

run

the

sample

program

now.

To

execute

(run) a

program

you

must

tell

the

computer

where

the

starting

point

of

the

program

is.

lt)

the

sample

program

the

starting

point

is

at

the

beginning

instruction

(ADDR 0000);

However,

not

all

programs

start

at

their

beginning.

Type:

0-0-0-0

RUN DISPLAY

shows:

00

the

program

countiri.g

This

tells

the

monitor

to

execute

a

program

starting

at

location

0000.

If

all

is

well

your

display

should

have

started

with

00

and

should

be

counting

its

way

to

99

at

which

time

it

will

start

over.

It

will

take

approximately

30

seconds

to

count

from

00

to 99.

If

your

display

is

not

counting

then

something

is

wrong

and you

should

go

back

and

examine

the

program

for

errors.

Notice

that

touching

keys

on

the

keyboard

produces

no

results

since

the

computer

is

running

the

sample

program

and

not

the

monitor

program.

Keyboard

control

can

only

be

regafaed

by

pressing

the

"RESET"

button

which

causes

the

computer

to

return

to

the

monitor

program.

19

MODIFYING

THE

PROGRAM

Y

ou

can

make

your

computer

count

faster

or

slower

by changing

the

speed

setting

at

address

0008.

To

make

it

count

faster,

a

smaller

number

should

be

sub-

stituted.

For

example;

Type:

RESET

0-0-0-8

DISP

2-0

ENTER

0-0-0-0

RUN

DISPLAY

shows:

00

08

50

20

es

00

counting

This

will

cause

the

counting

rate

to

increase

by

more

than

double.

Notice

that

the

operations

performed

were:

(

o-o-o-8-DISPLAY)

set

the

pointer

to

location

0008;

(2-0-ENTER)

enter

20

in

location

0008;

(0-0-0-0-RUN)

run

the

program

starting

at

location

0000. (Note:

the

speed

setting

is

in

hex;

therefore

the

largest

number

that

can

be

used

is

"FF"

and

not

"99".)

·

Y

ou

can

change

the

number

that

the

program

counts

with

by

changing

location

0012

(presently

"Ol").

Try

"05".

For

an

interesting

effect

restore

location

0012 to

"Ol"

and

then

change

locations

0007

and

0008 to "AA"

and

"EA"

respectively.

(The

easiest

way to

accom-

plish

this

is

as

follows:

0-0-0-7-DISPLAY-A-A-ENTER-E-A-ENTER-O-O-l-2-

DISPLAY-0-1-ENTER).

This

replaces

a

two-byte

instruction

(LDX #$50)

with

two

one-byte

instructions

("TAX"

and

"NOP")• Now

run

the

program

and

note

that

the

effect

produced

is

to

count

slower

as

the

number

gets

larger.

It

is

left

as

an

exercise

to

the

user

to

determine

why

these

changes

produce

this

effect.

If

you would

like

for

the

computer

to

teach

you how

to

Count

in

hex

then

restore

the

program

to

normal

and

then

Change

location

OOOF

to

"D8".

Run

the

program

and

watch

the

display

count

up

in

hexadecimal

(You

may

want

to slow

it

down

as

noted

above).

OTHER

GOODIES

IN

PIEBUG

So

far

you

have

used

four

control

keys

(DISPLAY,

ENTER,

BACKSPACE,

and

RUN).

Four

more

remain

tobe

defined

(POINTER HIGH,

POINTER

LOW,

TAPE,

and

RELATIVE ADDRESS COMPUTE).

Since

the

pointer

contains

four

digits

but

the

display

can

only show two

digits,

the

pointer

is

divided

into

two

segments:

POINTER HIGH

and

POINTER

I.DW.

Each

contains

two

digits

of

the

pointer.

POINTER

HtGH

(PH)

AND

POINTER

LOW

(PL)

These

two

keys

are

used

to

see

exactly

what

address

the

pointer

contains.

Touching

key

"PH"

will

display

the

first

two

digits

of

the

pointer

and

likewise

"PL"

will

display

the

last

two

digits.

Normal

sequence

is

'·'PH-PL-DISP"

which

will

show

you

2othe

pointer

and

then

the

contents

of

the

location

it's

pointing

to.

TAPE

lf

you

have

the

cassette

tape

option

this

key

can

be

used

to

save

programs

on

tape

and load

them

back

into

the

computer

at

a

later

time.

Details

of

its

use

are

supplied

with

the option.

***CAUTION***

lf

your

computer

does

not

have

this

option and you touch

this

key, you

may

lose

control

of

the

computer

and

it

may

overwrite

portions

of

your

program

with

garbage

and

it

may

just

eat

your

lunch!

RELATIVE

ADDRESS

COMPUTE

As

you

learn

to

write

programs

you

will

develop a

need

to

compute

relative

addresses.

These

addresses

take

only two

digits

instead

of

the

usual

four

and

can

be

computed

by

hand. However, a much

faster

and

more

accurate

way

is

to

let

the

computer

do

it

at

the touch of a button.

The

monitor

contains

a

program

to compute

relative

addresses

for

you.

To

use

it

you

simply

enter

a

program

as

you

normally

would and

then

when you

come

to a

brauch

operand,

instead

of

typing

in

the

operand

(relative

address)

type

in

the

absolute

(4-digit)

address

of

the

destination

and

then

touch

the

"REL"

key.

Instantly

the

correct

operand

will

appear

in

the

display.

lf

the

display

indicates_

11

00

11

then the

destination

was

out

of

range.

Otherwise

you

may

enter

the

operand

with

the

"ENTER"

key.

Part

of

the

sample

program

is

used

for

an

example.

Starting

at

location

0009;

Type:

0-0-0-9

DISP

C-8

ENTER

D-0

ENTER

0-0-0-9

REL

ENTER

DISPLAY shows: 09

X.X

es

X.X

DO

X.X

09

FD

When you touched

the

"REL"

key

the

display

should have

indicated

"FD"

9

as

shown

in

the

program.

DEBUGGING

YOUR

PROGRAMS

Normally

a new

program

will

never

run

properly

the

first

time

(this

is

a

perfect

example

of

Murphy's

Law:

lf

anything

can

go

wrong,

it

will!).

Therefore

some

means

of

determining

what

went

wrong

with

your

program

is

necessary.

Most

computers

use

a

"breakpoint"

for

this

purpose.

The

idea

behind

it

is

to

stop

the

computer

at

some

specified

point

in

your

program

and

display

the contents of

the

processor's

internal

registers

as

well

as

any

other

memory

locations

pertinent

to

your

program

(such

as

those

containing

status

information).

By doing

this

you

can

compare

the

status

of

the

computer

against

what you thought

it

should

be

at

that

point.

lf

it

doesn't

agree

then

you

have

a

clue

to

what

is

wrang

and

by

placing

the

breakpoint

at

in

your

program

you

can

determine

just

where

it

is

that

you and

your

computer

disagree.

21

Paia 8700 Guide

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