North_Star_Z80A_Processor_Board_ZPB A_Rev_2_1977 North Star Z80A Processor Board ZPB A Rev 2 1977

/

NORTH

STAR

*

COMPUTERS,

INc.

2547 Ninth Street · Be

rk

el

ey,

Ca

li

fornia

94

710 •

(4

15) 549-0

85

8

I

North

Star

Z80A. PROCESSOR

BOARD

ZPB-A

/

Contents

Cautions

• . . . . . • • . . . . . . . 2

Introduction

.

.........•

3

Limited

Warranty

. . . . • • • . . . .

..

4

Out

of

Warranty

Repair

. . . . . . . • 4

ZBP-A

Parts

List

. • . . • . . . • . .

.•

5

PROM

Opt

i

on

Parts

List

. . . . . . . .

•.

6

A~sembly

I

n

form~tion

.

..

•

.....

7

Figure

lA:

Component

Identification

.

10

ZPBAssembly

. .

..

•.•.•...•

11

ZBP

Board

Checkout

.

..•..

..

15

PROM

Option

Assembly

and

Checkout

. . 20

Con

f

iguration

Options

. . 4

•••••••

21

The

o

ry

of

Operation

. . . . . . . . . 24

Append

i x

1:

Pulse

Signal

Detection

.•..

28

Appendix

2:

S-100

Bus

Signals

....•.

29

Assembly

Figures

. . . • . . . . .

30

Schematic

Drawings

. . . .

.•

. .

..

31

Copyright

1977,

North

Star

Co

m

puters,

I

nc.

REVISION 2

CAUTIONS

1.

Correct

this

document

from

the

errata

sheets,

if

any,

before

doing

anything

else.

2.

Building

this

product

from

a

kit

is

a

complex,

demanding

project.

It

should

not

be

attempted

without

prior

kit

building

experience.

3.

Do

NOT

insert

or

remove

the

ZPB

from

the

computer

while

the

power

is

turned

on.

Note

that

the

power

is

not

completely

off

until

the

capacitors

have

discharged,

several

seconds

after

turning

of

the

power

switch.

.

4.

Do

NOT

insert

or

remove

IC's

from

the

board

while

the

power

is

turned

on.

5.

Be

sure

each

5

volt

regulator

is

generating

5

volt

output

voltage

before

installing

any

IC's.

6.

Be

careful

to

insert

all

IC's

in

correct

positions

and

with

correct

orientation.

Be

sure

all

IC

pins

are

correctly

inserted

into

the

socket

holes

and

are

not

bent

under

the

IC

and

are

not

outside

the

socket.

7.

Carefully

observe

the

anti-static

handling

procedure

for

the

static

sensitive

devices

(these

are

the

Z80A

and

the

2708

PROM

in

the

PROM

option).

The

procedure

is

described

in

the

Assembly

Information

section

of

this

manual.

North

Star

Z80A

PROCESSOR

BOARD

2

INTRODUCTION

The

North

Star

Computers

Z80A

Processor

Board

(ZPB)

provides

Z80

microprocessor

capability

on

the

S-100

bus.

The

use

of

the

Z80A

chip

allows

full

speed

4MHz

operation

as

a

standard

feature.

The

ZPB

can

be

used

in

any

standard

S-100

bus

computer

and

will

operate

in

conjunction

with

nearly

all

other

S-100

bus

boards.

However,

the

ZPB

has

been

specifically

designed

to

integrate

into.

the

North

Star

Computers

HORIZON

computer

system.

In

addition

to

the

Z80A

microprocessor

and

support

logic

to

interface

to

the

standard

S-100

bus,

the

ZPB

contains

the

following

features

and

options:

1.

AUTO-JUMP

feature

that

will

cause

an

automatic

jump

to

any

address

at

power-on

or

reset.

2.

VECTORED

INTERRUPTS.

ZPB

logic

will

respond

to

eight

levels

of

interrupt

requests,

determine

the

highest

priority

request

pending

and

generate

the

appropriate

RST

instruction.

The

logic

may

be

disabled

to

allow

the

function

to

be

performed

on

another

board.

3.

FRONT

PANEL

INTERFACE

for

direct

connection

to

IMSAI

and

other

similar

front

panels.

40

ADDRESS

MIRROR

feature

to

simulate

the

input/output

characteristics

of

the

8080

mieroprocesso[.

This

feature

maintains

compatibility

with

some

S-100

bus

peripheral

boards.

Address

mirroring

may

be

disabled

to

allow

use

of

the

more

powerful

Z80

protocol.

5.

PROM

OPTION. lK

of

2708

type

erasable

PROM

can

be

'added

to

the

ZPB.

This

allows

configuration

of

systems

that

requ1re

resident

monitor

and

bootstrap

programs.

If

you

have

purchased

the

ZPB

as

a

kit,

firyt

skim

this

entire

manual.

Before

beginning

assembly,

careful~y

read

the

Assembly

Information

section.

Whether

you

purchased

the

ZPB

as

a

kit

or

assembled,

read

the

Configuration

section

before

attempting

to

use

the

ZPB.

Note

that

a

Z80

Technical

Manual

has

been

included

to

fully

describe

the

operation

of

the

Z80A.

3

North

Star

Z80A

PROCESSOR

BOARD

LIMITED

WARRANTY

North

Star

Computers,

Inc.

warrants

the

electrical

and

mechanical

parts

and

workmanship

of

this

product

to

be

free

of

defects

for

a

period

of

90

days

from

date

of

purchase.

If

such

defects

occur,

North

Star

Computers,

Inc.

will

repair

the

defect

at

no

cost

to

the

purchaser.

This

warranty

does

not

extend

to

defects

resulting

from

improper

use

or

assembly

by

purchaser,

nor

does

it

cover

transportation

to

the

factory.

Also,

the

warranty

is

invalid

if

all

instructions

included

in

the

accompanying

documentation

are

not

carefully

followed.

Should

a

unit

returned

for

warranty

repair

be deemed

by

North

Star

Computers,

Inc.

to

be

defective

due

to

purchaser's

action,

then

a

repair

charge

not

to

exceed

$30

without

purchaser's

consent

will

be

assessed.

ANY

UNIT

OR

PART

RETURNED

FOR

WARRANTY

REPAIR

MUST

BE

ACCOMPANIED

BY

A

COpy

OF

THE

ORIGINAL

SALES

RECEIPT.

This

warranty

applies

to

units

located

outside

the

United

S~ates

of

America

only

if

all

costs

and

arrangements

for

transportation

of

the

product

to

and

from

the

factory

are

borne

entirely

by

the

customer.

This

warranty

is

made

in

lieu

of

all

other

warranties,

expressed

or

implied,

and

is

limited

to

the

repair

or

replacement

of

the

product.

No

warranty,

expressed

or

implied,

is

extended

concerning

the

completeness,

correctness,

or

suitability

of

the

North

Star

equipment

for

any

particular

application.

There

are

no

warranties

which

extend

beyond

those

expressly

stated

herein.

OUT·OF

WARRANTY

REPAIR

If

your

unit

is

out

of

warranty

and

you

are

unsuccessful

at

diagnosing

or

repairing

the

problem,

out-of-warranty

service

may

be

arranged

with

a

local

dealer

or

other

experienced

local

computer

technician.

Alternatively,

any

North

Star

products

may

be

shipped

PREPAID

to

the

North

Star

address

with

a

clear

written

description

of

the

problem.

Include

as

many

details

as

possible

about

the

problem

and

about

your

system

configuration.

Your

unit

will

be

returned,

C.O.D.,

within

30

days

after

receipt

by

North

Star.

Out-of-warranty

repair

service

is

billed

at

the

rate

of

$25.00

per

hour.

If

you

wish

to

place

an

upper

limit

on

the

amount

of

time

spent

on

your

unit,

mention

this

in

the

written

description.

North

Star

Z80A

PROCESSOR

BOARD

4

ZPB-A

PARTS

LIST

1 ZPB

Manual

1

Z80

Technical

Manual

1 ZPB

printed

circuit

board,

5"

x

Ie"

1

40-pin

IC

socket

7

20-pin

IC

sockets

14

l6-pin

IC

sockets

14

14-pin

IC

sockets

1

16-pin

DIP

header

1

lN4l48

diode

2 5

volt

regulators,

7805

or

340T-5

2

heat

sinks,

6107B-14

I

crystal,

8MHz

2

6-32x3/B"

machine

screws

2

#6

lock

washers

2

6-32

nuts

Integrated

Circuits

3

74LS00

1

74LS132

2

74LS02

1

74LS148

1

74LS03

'J

74LS175

..J

2

74LS04

7

74LS241

J

74LS08

2

74LS257

1

74LS14

1

7404

1

74LS32

<

74367

1

74LS74

1

8T97

2

74LS75

1 Z80A

Resistors

1

100

ohm

(brown-black-brown)

1

330

ohm

(orange-orange-brown)

2

470

ohm

(yellow-violet-brown)

11

lK

ohm

(brown-black~red)

I

10K

ohm

(brown-black-orange)

4

lK

ohm

networks,

Part

No.

l0-9-l-R1K

1

2.2K

ohm

network,

Part

No.

10-9-l-R2.2K

Capacitors

I

1

19

2

1 .

1

5

33pf

470pf

.047uf

6.8uf

39uf

100uf

dipped

mica

(may

be

marked

"330J03")

dipped

mica

ceramic

disc

dipped

tantalum

dipped

tantalum

electrolytic

North

Star

Z80A PROCESSOR

BOARD

PROM

OPTION

PARTS

LIST

2

74LS136

IC

1

2708

EPROM

1

+12

volt

regulator,

78L12

1

-5

volt

regulator,

79L05

1

24-pin

IC

socket

3

14-pin

IC

sockets

1

14-pin

DIP

header

1

lK

resistor

(brown-black-red)

1

3.9K

resistor

(orange-white-red)

1

3.9K

resistor

network,

Part

No.

10-9-1-R3.9K

4

2.2uf

dipped

tantalum

capacitors

North

Star

Z80A

PROCESSOR

BOARD

6

ASSEMBLY

INFORMATION

Read

completely

through

each

section

before

beginning

the

first

instruction

step

of

that

section.

Perform

all

operations

in

the

sequence

indicated.

Read

each

step

entirely,

including

any

notes

that

accompany

the

step,

before

beginning

to

follow

the

step.

WORK

AREA

AND

TOOLS

Start

with

a

clean,

well-lit

and

well-ventilated

area

to

work.

The

area

should

be

large

enough

to

accommodate

the

kit,

tools,

parts

and

assembly

instructions~

Suggested

tools

are:

screwdrivers,

needle-nose

pliers,

diagonal

cutters,

soldering

iron,

solder,

and

masking

tape.

A number

of

tests

will

require

using

a

YOM

(ohmmeter-voltmeter),

or

VTVM.

Also

highly

desirable,

but

not

necessary,

are

an

IC

inserter,

a

screw-holding

screwdriver,

an

oscilloscope

or

logic

probe,

and

an

extender

card.

[Note

that

if

you do

not

have

an

oscilloscope

or

logic

probe,

waveforms

can

be

detected

by

one

of

the

procedures

described

in

Appendix

1.]

SOLDERING

TIPS

For

best

results

use

a

15

to

25

watt

soldering

iron

or

an

iron

with

a

temperature

controlled

tip

(approximately

700

degrees).

The

tip

should

be no

wider

than

the

solder

pads

on

the

printed

circuit

board.

Use

only

a

fine

gauge

rosin

core

solder

(60/40

or

63/37).

Do

NOT

use

acid

core

solder

as

this

can

severely

damage

a

printed

circuit

board.

When

soldering,

keep

the

soldering

iron

tip

on

the

pad

just

long

enough

for

the

solder

to

completely

flow.

If

the

solder

does

not

draw

up

the

wire

then

more

solder

is

required.

Do

not

use

so

much

solder

that

it

overflows

the:

pad.

i~

a

solidified

joint

is

not

sn1ny,

1L

may

be

a

cold

solder

joint

and

should

be

remelted.

The

soldering

iron

tip

should

be

cleaned

frequently

by

wiping

on a damp

sponge

When

you

have

completed

assembly

of

a

board,

inspect

it

for

unintended

solder

connections

or

"bridges",

as

well

as

unsoldered

leads.

After

soldering,

it

is

recommended

that

the

rosin

flux

be

removed

from

the

board

using

flux

remover,

FREON

or

paint-thinner

type

solvent.

This

will

make

looking

for

soldering

problems

easier

and

give

the

board

a

clean,

professional

appearance.

IC

SOCKET

INSTALLATION

Integrated

circuit

(IC)

sockets

can

be

installed

by

first

inserting

them

into

the

printed

circuit

board,

then

placing

another

flat

board

over

the

IC

sockets

and

finally'

turning

over

this

sandwich.

Be

sure

that

each

IC

socket

is

inserted

into

the

proper

location

and

is

oriented

such

that

1

of

the

socket

corresponds

to

the

1

indication

on

the

PC

board

layout

legend.

(Refer

to

figure

IA

to

identify

I on

an

IC

socket.)

To

solder

IC

sockets,

first

solder

just

two

opposite

corner

pins

7

North

Star

Z80A

PROCESSOR

BOARD

for

all

sockets

being

installed.

Then

remelt

the

corner

connections

while

applying

pressure

down on

the

board.

This

will

remove

any

gaps

'that

may

be

present

between

the

IC

sockets

and

the

PC

board.

Finally,

solder

the

remaining

pins

of

the

IC

sockets.

DIP

HEADER

SOLDERING

When

making

jumper

connections

on

a DIP

header,

solder

resistor

or

capacitor

lead

snippings

between

the

leads

to

be

connected.

When

more

than

two

pins

are

to

be

connected

together,

bend

a

sIngle

wire

so

that

it

routes

to

each

pin,

and

solder

each

once.

Insert

the

header

in

an

IC

socket

on a

PC

board

to

hold

it

during

soldering.

Overheating

the

pins

with

t~e

soldering

iron

will

melt

the

plastic

of

the

header.

If

there

are

multiple

jumpers

on

a

header,

make

sure

that

no

unintended

connections

are

made by

carefully

routing

the

jumpers,

or

by

insulating

each

jumper

with

some

wire

insulation.

RESISTOR

AND

CAPACITOR

INSTALLATION

To

install

resistors

or

capacitors,

first

make

right

angle

bends

in

the

leads

to

fit

the

PC

board

hole

spacing.

(Some

capacitor

leads

are

already

appropriately

spaced

and

do

not

need

bending.)

Then

insert

the

leads

as

far

as

possible

through

the

correct

.

holes

in

the

PC

board

and

spread

the

leads

slightly

on

the

solder

side

of

the

board

to

keep

the

part

in

place.

After

a

grou~

of

resistors

or

capacitors

has

been

inserted,

then

solder

the

leadS

on

the

solder

side

of

the

board

and

snip

off

the

excess

leads

as

close

to

the

board

as

possible.

Use

caution

to

avoid

eye

injury

from

flying

bits

of

wire.

Save

the

lead

clippings

for

later

use

in

making

jumper

connections.

PRINTED

CIRCUIT

BOARD

LAYOUT

The

white

component

layout

legend

is

printed

on

the

component

side

of

a

printed

circuit

(PC)

boar~.

All

components

are

inserted

from

this

side

(component

side)

and

soldered

on

the

other

side

(solder

side).

Locations

on

the

PC

board

are

identified

by

two-character

codes

as

marked

on

the

board:

a

digit

followed

by

a

letter

indicating

the

horizontal

and

vertical

coordinates

of

the

location.

Note

that

in

North

Star

kits,

IC's

can

be

found

on

styrene

pads

in

positions

corresponding

to

their

intended

locations

on

the

PC

board.

nrimbering

conventions

for

the

S-l~~

edge

pins

are

as

follows:'

When

viewing

the

component

side

of

the

board

(with

the

edge

facing

down),

pins

1,2,

•••

,

5~

range

from

left

to

right.

When

viewing

the

solder

side

of

the

board,

pins

l~~,

99,

•••

, 51

range

from

left

to

right.

North

Star

Z8~A

PROCESSOR

BOARD

8

MaS

INTEGRATED CIRCUIT

HANDLING

Some

North

Star

PC

boards

use

some

MaS-type

IC's.

These

parts

are

identified

as

such

in

the

instructions.

MaS

devices

can

be

damaged

by

static

electricity

discharge,

so

special

handling

is

necessary

to

protect

them.

Handle

MaS

devices

as

little

as

possible

and

avoid

touching

the

pins.

Place

the

conductive

foam

or

tube

which

contains

the

MaS

device

onto

the

PC

board

before

removing

the

device

from

the

foam

or

tube.

Also,

be

sure

both

hands

are

touching

the

foam

or

tube

when

the

device

is

removed

from

the

foam

or

tube.

Once

a

MaS

device

has

been

installed

in

a

PC

board,

handle

the

.board

as

little

as

possible.

Of

course,

never

insert

or

remove

any

IC

while

power

is

applied

to

the

board,

and

never

remove

or

insert

a

PC

board

while

power

is

applied

to

the

motherboard.

9

North

Star

Z80A PROCESSOR

BOARD

c::=======~~

100

MFD

)J::=======:3

positive (+) lead

\};...

.

Axial Lead

Electrolytic Capacitor

========(€]DDD[:)~======~

Transistor and

Regulator (To-92)

Resistor

Quick-Connect

Lug

Integrated Circuit (lC)

Ceramic

Disc

Capacitor·

Ii'

-

Dipped

Mylar

Capacitor

I C Socket

Dipped

Mica

Capacitor

Figure

1A.

Identification

and

orientation

of

components.

Resistor Network

Dipped

Tantalum

Capacitor

positive

(+) lead

DIP

Header

ZPB

ASSEMBLY

Before

beginning

assembly

of

the

ZPB,

first

check

that

you

have

all

the

parts

listed

in

the

parts

list.

Note

tha

t

in

the

f01lowing

instructions,

"le

ft"

and

"r

ight"

refer

to

those

directions

when

viewing

the

component

side

of

the

PC

board

with

the

100-pin

edge

facing

down.

Using

an

ohmmeter,

check

for

open

circuits

between

the

pair

of

solder

pads

for

each

of

the

following

seven

capacitor

locations:

C22,

C23,

C25,C26,

C27, C28,

and

C29.

If

any

shorts

are

found,

locat~

and

correct

the

problem

or

return

the

PC

board

for

repla'cement.

Insert

and

solder

the

40-pin

IC

socket

at

location

3C,

following

the

procedure

given

in

the

Assembly

Information

section.

Insert

and

solder

the

seven

20-pin

IC

sockets

with

correct

orientation.

Insert

and

solder

a

16-pin

IC

socket

at

location

IG.

Note

that

this

socket

has

reverse

orientation

from

all

the

others,

with

I

in

the

upper

right

corner.

ZS.

Insert

and

solder

the

remaining

thirteen

16-pin

sockets

with

correct

orientation.

t';;"2\

~

zs.

11

Insert

and

solder

the

fourteen

14-pin

sockets

with

correct

orientation.

Do

not

install

sockets

in

locations

5C,

5D,

and

5E

(inside

dashed

line)

unless

you

are

assembling

the

PROM

option

at

this

time.

Insert

and

solder

the

five

single-in-line

(SIP)

resistor

networks

labeled

RNI,

RN2, RN4, RN5,

and

RN6

on

the

layout

legend.

RN6

is

a

2.2K

ohm

network

and

the

remaining

four

are

IK

ohm

networks.

RN3

is

part

of

the

PROM

option.

Orient

each

SIP

so

the

end

marked

with

a "I"

(sometimes

this

end

has

a

beveled

corner)

corresponds

to

the

end

marked

with

a

dot

on

the

layout

legend.

Insert

and

solder

the

following

sixteen

resistors.

Refer

to

the

Assembly

Information

section

for

resistor

installation

procedures.

Resistor

Value

Color-code

Location

(~

Rl

470

ohm

yellow-violet-brown

IF

North

Star

Z80A PROCESSOR

BOARD

~~

R2

470

ohm

yellow-violet-brown

IF

R3

IK

ohm

brown-black-red

2E

(V'j

RS

IK ohm

brown~black-red

SG-

(~

R6

IK ohm

brown-black-red

4F

(

R7

330

ohm

orange-orange-brown

4C

(v)

R8

IK

ohm

brown-black-red

6B

(~R9

IK

ohm

brown-black-red

6B

(.

RII

IK

ohm

brown-black-red

4G

(1

Rl2

IK

ohm

brown-black-red

7C·

(Vr

R13.

lK

ohm

brown-black-red

7A

(~

Rl4

IK

ohm

brown-black-red

7A

( RIS lK

ohm

brown-black-red

8F

(v)

Rl6

10K

ohm

brown-black-orange

8G

(

V(

Rl7

100

ohm

brown-black-brown

8G

(v

R18

lK

ohm

brown-black-red

8G

~

Insert

and

solder

the

lN4l48

diode

at

location

8G. The

end

of

the

diode

marked

with

a

band

is

the

cathode

end

and

should

be

oriented

toward

the

top

of

the

board.

/ZrD

Insert

and

solder

the

l0flh:lf.

electrolytic

cap~cito.r

(C29)

~

located

near

8A. The

posltlve

end

(marked

wlth

a "+"

or

a

red

dot)

should

be

oriented

toward

the

right

as

indicated

on

the

layout

legend.

Some

capacitors

mark

the

negative

end

with

a

"-"

instead

of

the

positive

end.

I .

~.l.

Insert

and

solder

the

39uf

tantalum

capacitor

(C2l)

near

~

location

7G.

Be

sure

to

orient

the

capacitor

so

that

the

lead

marked

with

a "+"

is

inserted

through

the

hole

marked

with

a

"+".

~.

Insert

and

solder

the

two

6.8uf

tantalum

capacitors

(C22

and

~C23)

at

locations

8F

and

8G.

Be

sure

to

orient

the

'capacitors

so

that

the

lead

marked

with

a "+"

is

inserted

through

the

hole

marked

with~a

"+".

G.l:V

Insert

and

solder

the

470pf

dipped

mica

capacitor

(Cl)

at

location

IF.

Some

470pf

capacitors

are

marked

"47lJO".

@~Inser~

and

solder

the

33pf

dil?ped'

mica

capacitor

(CS)

at

.

locatlon

2F.

Some

33pf

capacltors

are

marked

"330J03".

<iI0rnsert

and

solder

the

nineteen

ceramic

disc

bypass

capacitors

in

locations

marked

with

an

asterisk

on

the

layout

legend.

rZl~.Insert

and

solder

the

8MHz

crystal

at

location

IF.

Make

~

right

angle

bends

in

the

two

leads

so

the

crystal

will

lie

parallel

with

the

PC

board.

To

hold

the

crystal

package

in

place,

use

a

piece

of

snipped

resistor

lead

to

solder

the

top

of

the

crystal

package

to

the

corresponding

hole

in

the

board.

A

little

space

should

be

left

between

the

cryst~l

and

the

PC

board

to

avoid

the

possibility.of

shorts.

North

Star

Z80A

PROCESSOR

BOARD

12

.

NOTE:

The

BMHz

crystal

is

used

for

4MHz

operation

of

the

processor.

If

2MHz

operation

is

desired,

then

a

4MHz

crystal

(not

supplied)

should

be

used.

See

the

Configuration

section

for

details

•.

Recheck

the

circuiis

between

the

capacitor

leads

as

in

step

Zl

and

make

sure

they

are

still

open

circuits.

Note

that

the

capacitors'which

have

been

installed

may

cause

the

ohmmeter

needle

to

jump when

first

contact

is

made

but

the

indication

should

rapidly

return

to

a

high

resistance.

(~

Insert

and

so~der

the

tWO.5-volt

regulators

(03

and

Q4).

\J

These

parts

will

be

marked

"7805"

or

"340T-5".

Bend down

the

three

leads

of

the

regulator

90

degrees

so

that

the

leads

go

into

the

correct

holes

while

the

machine

screw

holes

line

up.

Install

the

heat

sink

and

regulator

so

that

the

following

sequence

results

from

bottom

to

top:

6-32

machine

screw

head,

PC

board,

heat

sink,

regulator,

lock

washer,

and

nut.

Finally,

make

sure

the

leads

do

not

touch

each

other

or

the

heat

sinks

and

then

tighten

the

machine

screw

and

solder

the

regulator

leads.

NOTE:

Heat

sink

grease

may

be

used

though

it

is

not

generally

needed.

Tightening

the

bolts

too

tight

can

crack

the

PC

board.

e C

/,..

"'1.-:; !.

Cf1

( c

?.

'!>::.

~,O

'-

V

Z19.

with

the

computer

power

off,

plug

the

partially

assembled

board

into

the

motherboard.

Then

turn

on

the

power.

with

a

DC

volt

meter

check

that

both

regulators

are

generating

5

volts

output.

These

voltages

can

be

measured

across

the

pins

of

C22

and

C23.

wait

a few

minutes

and

measure

again.

The

regulators

should

not

get

very

hot

in

this

configuration~

However,

with

all

parts

installed

it

is

normal

for

the

regulator

to

feel

quite

hot

to

the

touch.

Remember

to

turn

off

the

power

before

removing

the

board.

Construct

a

16-pin

DIP

header

with

jumpers

set

up

for

a

starting

address

of

EB00

hex.

This

is

the

standard

HORIZON

starting

address.

If

some

other

starting

address

is

desired,

change

the

header

after

completing

the

checkout

instructions.

See

figure

lZ

for

the

details

of

the

header

configuration.

Refer

to

the

Assembly

Information

section

for

header

construction

procedures.

Plug

the

completed

header

into

location

2E

(the

POJ

ADDRESS

socket)

with

the

correct

orientation.

/

---,,!>"""t-

2.

...

5,

DCj

G

'1,..

~

-;.

.)

I

00

Insert

the

33

integrated

circuits

(all

exce?t

the

z80A

chip).

Be

sure

that

all

IC's

have

1

oriented

to

the

bottom

left

corner.

Do

not

insert

any

IC's

inside

the

area

for

the

PROM

option

(outlined

with

a

dashed

line).

SVO

/J'YltV

TOT r

fJJ!O

-z..-1?O!

Recheck

the

regulator

output

voltages

as

in

step

Zl9.

13

North

Star

Z80A

PROCESSOR

BOARD

Z23

•.

Remove

the

PC

board

from

the

computer

and

then

plug

in

the

Z80A

chip

with

correct

orientation.

Refer

to

the

Assembly

Information

section

for

MOS

device

handling

procedures.

Z24.

Inspect

the

board

in

a

good

light

to

insure

that:

A.

all

solder

joints

are

good,

i.e.

there

are

no

bridges

of

solder

beween

adjacent

solder

joints,

no

unsoldered

joints,

and

no

cold

solder

joints

indicated

by

a

dull

finish

on

the

solder.

B.

all

IC

pins

are

in

the

IC

socket

holes,

not

outside

the

socket

and

not

folded

under

the

chip.

Pins

folded

under

can

often

be

detected

by

sighting

down. a row

of

chips

to

see

if

there

is

any

blockage

of

light

under

the

chips.

C.

all

parts

are

installed

in

the

correct

locations

with

the

correct

orientation.

The

ZPB

is

now

completely

assembled.

Proceed

to

the

RAM

Board

Checkout

section.

North

Star

Z80A

PROCESSOR

BOARD

14

RAM

BOARD

CHECKOUT

The

following

checkout

procedure

should

be

followed

for

a

newly

assembled

board.

It

can

also

be

used

to

diagnose

problems

in

previously

operational

boards.

This

checkout

procedure

assumes

that

no

other

board

besides

the

ZPB

is

plugged

into

the

S-100

bus.

This

makes

it

possible

to

get

the

ZPB

operational

even

if

no

other

board

in

the

system

is

yet

working.

This

procedure

assumes

only

that

the

correct

unregulated

voltages

have

been

applied

to

the

bus,

that

the

computer

has

a

reset

switch,

and

that

the

bus

lines

are

not

shorted

to

each

other.

The

following

terms

are

used

in

specifying

expected

test

results.

GND

LOW

HIGH

+5V

AC

ground,

0

volts

DC

logic

zero,

0-.7

volts,

normally

about

.3

volts

logic

one,

2.4-5.0

volts,

normally

about

3

volts

+5

volts

from

power

supply

Signal

with

pulses

(as

opposed

to

DC

signal)

When

referring

to

the

name

of

a

signal

from

the

schematic

drawings,

if

the

signal

is

identified

with

a

bar

over

its

name

then

the

name

of

the

signal

is

followed

by

a

slash

(e.g.,

STORE/)

in

the

checkout

instructions.

When

describing

an

AC

pulse,

the

notation

(±W,P)

refers

to

a

positive

or

negative

pulse

with

a

width

of

Wand

a

period

of

P.

For

example,

a

positive

pulse

of

width

125

nanoseconds

appearing

every

25

microseconds

would

be

represented

as

(+125ns,25us).

See

Appendix

1

for

details

on

how

to

detect

pulse

signals.

The

abbreviation

MB

before

a

number

indicates

a

bus

on

the

motherboard.

If

an

oscilloscope

will

be

used

to

test

the

board,

a

"scope

ground"

may

be

installed

by

soldering

a

"bridge"

of

jumper

wire

between

the

two

PC

board

holes

that

connect

edge

connector

pins

50

and

100

near

location

2A.

Note

that

either

of

the

two

regulator

machine

screws

can

also

be

used

for

ground

test

points.

~

Check

for

correct

clock

signals

on

the

ZPB

as

follows:

15

A.

Install

a

jumper

wire

at

PE

(near

location

4G)

if

the

PE

trace

was

has

been

cut.

B. Remove

the

lW

jumper

(near

location

6G)

if

it

was

previously

installed.

North

Star

Z80A

PROCESSOR

BOARD

c

•.

Install

a

jumper

wire

at

MW

(near

location

6A)

if

the

MW

trace

has

been

cut.

D.

with

the

computer

power

off,

install

only

the

ZPB

in

the

computer

motherboard.

E.

Turn

on

the

compu~er

power

and

check

for

the

following

signals.

Note

that'all

timing

signals~iven

below

assume

the

ZPB

is

configuredfRr

standard

4MHz

operation.

",

Signal

Location

Description

t

:fl~)

~

I-\.v,n-

{ qq'1

'bt-t

(91.

v-PHI

Z80

6

AC,

(+125ns,250ns)

......

VPHI 2

MB

24

AC,

(+

125ns,

25

0ns')

V;;HI 1

MB

25

AC,

(+62ns,250ns)

\ \

q"1

W

\

2MH

Z

CLOCK/

MB

49

AC,

(-250ns,500ns)

~"

If

any

of

these

are

wrong,

trace

back

to

the

crystal

to

determine

the

cause.

C1v~

This

step

will

check

the

reset

logic.

Use

the

same

setup

as

the

and

check

the

following

signals

while

alternately

depressing

and

releasing

the

computer

reset

switch.

Switch Switch

Signal

Location

Depressed

Released

RESET/

I/MB

75

LOW

HIGH

V7G

6

HIGH

LOW

RST/ y'5G

6

LOW

HIGH

POC/

","'MB

99

LOW

HIGH

Check

the

auto-jump

logic

as

follows:

A.

Leave

the

board

configured

as

in

the

B.

Turn

off

the

computer

power

and

remove

the

ZPB

from

the

computer.

Temporarily

connect

the

PRDY

signal

to

ground

by

soldering

a

piece

of

jumper

wire

beween

7F

5

and

7F

7

on

the

solder

side

of

the

ZPB.

C.

Install

only

the

ZPB

in

the

computer

'motherboard

and

then

turn

on

the

power

and

depress

and

release

the

reset

switch.

The

processor

should

pause

immediately

after

performing

the

auto-jump

sequence

and

just

before

executing

the

first

instruction

at

the

auto-jump

address.

Sheck

that

the

SMI

signal

at

motherboard

44

is

HIGH.~

D.

Assuming

the

jump

address

specified

on

the

header

at

location

E2

is

E800,

then

E800

should

be

on

the

motherboard

address

lines.

HIGH

signals

should

be

observed

on

the

following,

motherboard

pins:

North

Star

Z80A

PROCESSOR

BOARD

16

../

/'

./

V

pins

32,

85, 86,

and

87.

LOW

signals

should

be

observed

on

the

following

motherboard

pins:

I

v v V'"

Vv"

v'

v

V'/

"/'

.

pins

29,

30, 31,

33,

34,

37,

79,

80,

81, 83,

and

84

The

processor

should·

have

executed

a

single

instruction

(JMP

E800)

and

then

gone

into

a

wait

state

during

the

instruction

fetch

at

that

address.

The

Theory

of

Operation

section

describes

the

auto-jump

sequence.

If

SMI

is

high

but

the

address

is

wrong,

check

the

data

paths

through

the

POJ

header

and

multiplexors.

If

SMI

is

LOW,

skip

to

the

to

see

if

the

processor

can

execute

instructions

at

all.

If

SMI

has

an

AC

signal,

check

the

wait

logic

from

PRDY

to

WAIT/.

C4.

This

step

checks

out

the

Z80A

while

executing

a

one

instruction

program.

17

A.

With

the

power

off,

remove

the

jumper

from

PRDY

to

ground

from

the

ZPB.

B.

Turn

on

the

power

and

then

depress

and

release

the

reset

switch.

The

Z80

should

be

executing

an

RST

7

instruction

repeatedly.

Observe

that

all

the

data

input

(01)

lines

are

HIGH

by

checking

the

following

motherboard

pins:

.

t/./

/

~..

~(if

/

plns

41,

42,

43,91,

93, 94,

and 95

C.

If

you

have

an

oscilloscope,

then

check

that

the

signals

ZD0-ZD7

are

HIGH

during

Ml

at

the

Z80A

chip

pins:

/

pins

14,

15, 12,

8,

7,

9,

10,

and

13

~0

~!.-'-.

D.

Check

that

the

following

motherboard

address

lines

are

AC

signals:

v'

t/

V

pins

29-34,

37,

and

79-87.

E. The

RST

7

instruction

causes

a

subroutine

call

to

location

0038

hex,

thus

the

stack

address

stored

will

be

0039 hex

(stored

as

alternating

00

byte

and

39

hex

byte).

Thus,

observing

the

data

output

bus

(DO),

the

following

motherboard

bus

pins

should

always

be

LOW:

~!

\ Du,utcJ

(,...

tZ(;r~,)E::~:-;':

pins

35,

40,

88,

and

90.

and

the

following

motherboard

bus

pins

should

have

AC

signals:

pins

36,

38,

39,

and

89

North

Star

Z80A

PROCESSOR

BOARD

North

Star

Computers,

Inc.

2547

Ninth

Street

Berkeley,

California

94710

Gentlemen:

September

9,

1978

I

am

resonding

to

your

request

for

information

regarding

possible

errors

in

the

Horizon

documentation.

I'm

sure

it's

redundant

but

here

goes

anyway:

ZPB-A

board

checkout

procedure,

page

17,

par.

C4-E

is

no

longer

valid

due

to

the

addition

of

the

DO

bus

pull-up,

RN6.

These

lines

wi.ll

go

hi.gh

when

ever

the

DO-EN

line

disables

IC's

1

Band

1A

giving

an

AC

indication

during

the

test.

Incidently,

my

Horizon

I

kit

webt

together

beautifully

and

so

far,

seems

to

be

working

like

a

champ!

//f)

Check

for

the

following

signals

at

the

Z80

chip:

L,)f

Signal

PHI

Ml/

INT/

NMI/

WAIT/

RST/

Vcc

ground

Location

6

27

16

17

24

26

11

29

Description

AC,

(+125ns,250ns)

AC,

(-;,,500ns,2750ns)

HIGH

./

HIGH

+5V

GND

~The

following

signals

should

be

observed

.on

the

motherboard

bus

lines:

Signal

XRDY

VI0/

VII/

VI2/

VI3/

VI4/

VI5/

VI6/

VI7/

NMI/

STAT-DSBL/

CC-DSBL/

ADDR-DSBL/

DO-DSBL/

PHLDA

PWAIT

PINTE

SMI

SOUT

SINP

SMEMR

SHLTA

SSW-DSBL/

PMREQ/

PRFSH/

MWRITE

RUN

PINT/

PHOLD/

PSYNC

PWR/

PDBIN

SWO/

Location

3

~.

§

6

~

8

,9

3.13

.11

,12

·18

. '

Pln

19

,22

pin.·23

.:26

pin~

27

28

44

pin-45

t46

pin- 47

.48

r53

65

6

..

6

6j3

pin"7l

pin-73

pin~

74

76

17

78

97

Description

HIGH

LOW

HIGH

AC,

(+500ns,2750ns)

LOW

AC,

(+375ns,2750.ns)

LOW

HIGH

AC,

4-pulses

every

2750ns

AC,

(-475ns,2750ns)

AC,

(+250ns

twice,2750ns)

HIGH

AC,

3

+pulses

every

275f3ns

AC,

(-250ns

twice,

2750ns)

Z\C,

(+360ns,2750ns)

A~,

(-250ns

twice,

2750ns)

North

Star

Z80A

PROCESSOR

BOARD

18

If

these

checkout

steps

have

been

successful,

then

the

ZPB

has

successfully

done

an

auto-jump

and

executed

a

simple

program.

Therefore,

most

of

the

circuits

on

the

ZPB

have

been

tested.

The

ZPB

should

now

have

its

configuration

options

set.

Be

sure

to

remove

all

special

jumpers

added

during

the

checkout.

It

is

then

ready

to

be

used

in

conjunction

with

the

other

boards

in

the

computer

system.

If

the

PROM

option

is

being

used,

install

it

at

this

time.

Diagnosis

of

a·

problem

in

a

previously

operational

board

will

usually

be

successful

using

the

following

procedure:

1.

Determine

that

the

ZPB

is

in

fact

the

board

that

has

the

problem

by

attempting

to

use

it

in

another

computer.

2.

Check

that

the

regulator

outputs

are

correct.

Then,

in

an

orderly

fashion

begin

replacing

IC's

in

the

ZPB

with

known

good

parts

until

the

problem

disappears.

If

a

board

that

was

working

has

not

been

subjected

to

any

abnormal

abuse

then

an

IC

failure

will

be

the

cause

of

the

problem

in

nearly

every

case.

3.

If

the

board

is

still

failing

then

the

problem

may

be

a

result

of

any

of

the

following

less

likely

conditions:

dirty

edge

connector

contacts,

bad

parts

other

than

the

IC's,

bad

connection

in

an

IC

socket,

or

introduction

of

a

short

or

open

in

the

traces

on

the

board.

19

NorthStar

Z80A

PROCESSOR

BOARD

PROM

OPTION

ASSEMBLY

AND

CHECKOUT

Before

assembling

the

PROM

option,

the

rest

of

the

ZPB

should

be

completely

assembled

and

checked-out.

Pl.

Insert

and

solder

the

24-pin

IC

socket

at

location

4E

with

the

correct

orientation.

P2.

Insert

and

solder

the

three

14-pin

IC

sockets

with

correct

orientation.

P3.

Insert

and

solder

the

resistor

network

RN3

at

location

40

so

that

1

(or

the

beveled

corner)

corresponds

to

the

dot

on

the

layout

legend.

P4.

Insert

and

solder

R4

(3.9K,

orange-white-red)

at

location

3E

and

R10

(lK,

brown-blak-red)

at

location

5C.

P5.

Insert

and

solder

the

+12

volt

regulator

(~arked

~78L12~)

at

location

01

(near

location

8B).

Also

insert

and

solder

the

-5

volt

regulator

(marked

"79L05")

at

locatibn

02

(near

location

8B).

The

regulators

should

be

oriented

so

that

the

flat

sides

of

the

parts

face

the

direction

indicated

on

the

layout

legend.

P6.

Insert

and

solder

the

four

2.2uf

tantalum

capacitors

(C25,

C26, C27,

and

C28)

at

location

8B

oriented

so

that

the

leads

marked

with

a

"+"

correspond

to

the

holes

marked

with

a .,+"

on

the

layout

legend.

P7.

Using

the

14-pin

DIP

header

and

some

lead

snippings

construct

a

header

to

determine

the

PROM

location

in

memory.

Refer

to

the

Configuration

section

(step

J8)

for

details.

Plug

the

completed

header

into

location

5E

with

correct

orientation.

P8.

Enable

the

PROM

option

by

cutting

the

"PE"

trace

between

locations

3G

and

4G.

P9.

Insert

the

3

integrated

circuits

as

indicated

on

the

layout

legend

with

correct

orientation.

When

inserting

the

PROM

observe

the

MOS

device

handling

precautions

given

in

the

Assembly

Information

section.

P10.

The

PROM

option

can

now

be

checked

out

by

reading

the

contents

of

the

PROM

using

a

monitor

program

or

control

panel.

Note,

however,

that

control

panels

which

display

the

01

bus

(e.g.,

Altair)

will

not

display

the

PROM

contents.

North

Star

Z80A PROCESSOR

BOARD

20

CONFIGURATION

OPTIONS

There

are

a number

of

configuration

options

possible

on

the

ZPB

that

are

specified

by

wIrIng

jumpers

on

the

board.

The

desired

configuration

should

be

wired

according

to

the

following

instructions

before

the

board

is

used.

Jl.

Signal

grounding.

Backplane

pins

20

and

70

may

be

optionally

connected

to

ground.

These

connections

can

be

made by

installing

the

jumpers

labeled

"EC20/1

and

"EC70/1,

respectively,

located

at

6A.

These

connections

should

be

made

unless

these

grounds

would

interfere

with

the

operation

of

other

boards

on

the

bus.

Grounding

these

pins

will

reduce

backplane

noise

and

thus

provide

more

reliable

performance.

Both

pins

should

be

grounded

with

a

HORIZON.

20

should

not

be

grounded

for

use

with

the

IMSAI.

Neither

should

be

grounded

on

an

Altair.

J2.

Memory

wait

states.

The

"lW"

jumper

to

the

right

of

location

7G,

if

connected,

forces

at

least

one

wait

state

on

every

memory

or

I/O

reference

made by

the

processor.

(If

a memory

board

specifies

one

or

more

wait

states,

then

that

number

of

wait

states

will

be

used

for

references

to

that

board.)

The

jumper

should

be

installed

if

memory

in

the

system

is

not

fast

enough

to

run

with

zero

wait

states

at

4MHz

(about

300ns

or

faster)

and

the

memory'

itself

cannot

be

configured

to

have

one

wait

state.

If

you

are

not

sure

your

memories

are

this

fast,

connect

the

jumper

to

get

the

system

running

and

experiment

later.

The

North

Star

16K

RAM

Board

does

not

require

any

wait

states.

J3.

Processor

speed.

Normally

the

processor

runs

at

4MHz.

However,

provision

has

been

made

to

run

at

2MHz.

To

achieve

2MHz

operation,

replace

the

8MHz

crystal

at

location

IF

with

a

4MHz

crystal

(not

supplied).

Then

cut

the

"4"

trace

above

location

6F

and

install

the

"2"

jumper

instead.

This

keeps

the

clock

on

backplane

49

at

2MHz

as

required

by

some

S-

11313

bus

boards.

J4.

Address

mirroring.

As

required

by

some

S-100

bus

boards,

the

ZPB

simulates

an

8080

during

IN

and

OUT

instructions

by

driving

the

port

address

onto

both

8-bit

halves

of

the

address

bus.

To

disable

this

feature

and

take

advantage

of

the

greater

flexiblility

of

the

Z80,

cut

the

"AM"

(address

mirror)

trace

to

the

left

of

location

7F

and

install

the

"NM"

(no

mirror)

jumper

instead.

J5.

Control

panel.

The

ZPB

normally

generates

the

MWRITE

signal

to

backplane

68.

If

the

ZPB

is

used

in

systems

with

control

panels

or

other

boards

that

generate

MWRITE,

then

the

"MW/I

trace

below

location

6B

should

be

cut.

Leave

the

trace

in

place

for

use

in

the

HORIZON.

Cut

the

trace

when

used

with

an

Altair

or

IMSAI.

21

North

Star

Z80A

PROCESSOR

BOARD

J6

•.

Vectored

interrupts.

The

ZPB

is

supplied

with

logic

to

respond

to

an

interrupt

request

on

the

vectored

interrupt

request

liries

VI0-VI7

by

generating

the

indicated

RST

instruction.

This

logic

may

be

disabled

by

installing

the

"ID"

jumper

above

location

7E.

This

will

allow

some

other

board

to

respond

to

interrupt

conditions.

J7.

PROM

option.

If

the

PROM

option

is

installed,

then

the

"PE"

trace

to

the

left

of

16cation

3G

must

be

cut

to

en~ble

the

on-board

PROM.

J8.

PROM

Address

Selection.

The

lK

bytes

of

on-board

PROM

can

be

selected

to

reside

in

any

of

sixty-four

lK

regions

of

the

Z80

address

space.

The

address

selection

logic

compares

the

six

high

order

address

bits

(A10-A15)

from'

the

Z80

against

the

six

bits

specified

with

jumper

wires

on

the

header

at

location

5E.

Pins

8-13

correspond

to

the

six

address

bits

A10-A15,

respectively.

All

bits

that

should

match

a

"zero"

bit

should

have

their

corresponding

pins

connected

to

1

or

2

with

jumper

wires.

All

bits

that

should

match

a

"one"

bit

should

have

their

corresponding

pins

connected

to

6

or

7

with

jumper

wires.

Figure

IP

shows

the

jumper

assignments

and

some

examples.

J9.

Auto-Jump

Address

Selection.

Any

of

the

64K

different

addresses

may

be

specified

as

the

auto-jump

address

with

jumper

wires

on

the

16

header

at

location

2E.

The

eight

pins

9-16

on

the

header

correspond

to

pairs

of

address

bits

according

to

the

following

table.

Low

Addr

Bit

High

Addr

Bit

9 0 8

10

1 9

11

2

10

12

3

11

13

4

12

14

5

13

15

6

14

16

7

15

The

address

bit

pins

9-16

should

each

be

connected

to

one

of

the

pins

1-8

according

to

the

following

table:

Connect

to

1

or

2

if

both

the

high

nrder

and

low

order

address

bits

of

the

pair

are

"ones".

Connect

to

3

or

4

if

the

high

order

address

bit

is

a

"one"

and

the

low

order

address

bit

is

a

"zero".

Connect

to

5

or

6

if

the

high

order

address

bit

is

a

"zero"

and

the

low

order

address

bit

is

a

"one".

North

Star

Z80A PROCESSOR

BOARD

22

23

Connect

to

7

or

8

if

both

the

high

order

and

low

order

address

bits

of

the

pair

are

"zeros".

For

example,

if

bit

9

of

the

jump

address

is

a

"one"

and

bit

1

is

a

"zero"

then

10

should

be

connected

to

3

or

4.

If

jump

address

bit

15

is

a

"zero"

and

bit

7

is

a

"zero"

then

16

should

be

connected

to

7

or

8.

Figure

lZ

shows

the

jumper

assignments

and

some

examples.

North

Star

Z80A PROCESSOR

BOARD

THEORY

OF

OPERATION

Z80A

AND

CONTROL

CIRCUITS

The

primary

function

of

the

ZPB

is

to

interface

the

Z80A

processor

to

the

S-100

bus

with

its

control

lines.

The

following

'list

gives

the

S-L00

control

signals

along

with

pertinent

comments

about

their

use

and

derivation.

A

slaah

at

the

end

of

a

name

indicates

that

the

signal

is

active

low

(negative

logic).

Signal

22

19

23

68

78

26

74

73

28

65

12

99

72

ADDR-DSBL/

CC-DSBL/

DO-DSBL/

MWRITE

PDBIN

PHLDA

PHOLD/

PINT!

PINTE/

PMREQ/

PNMI

POC/

PRDY

Description

Disables

the

address

line

drivers

onto

the

S-100

bus

when

true.

Disables

drivers

for

PSYNC,

PDBIN,

PWAIT,

PWR,

PMREQ,

and

PRFSH

when

true.

Disables

the

data

output

bus

(DO)

drivers

when

true.

,

True

during

a memory

write

operation

of

the

Z80.

This

signal

should

be

disconnected

if

the

ZPB

is

used

in

a

system

where

MWRITE

is

generated

on

the

control

panel

board

or

some

other.board.

Indicates.

that

the

Z80

is

reading

the

DI-;-:'bus

during

a memory

read,

input,

or

interrupt

ackno~ledge

operation4

The

hold

acknowledge

response

by

the

Z80

to

a

hold

req~est

(PHOLD).

Indicates

that

the

Z80

execution

is

suspended

and

that

a

DMA

bus

operation

may

begin.

Used

to

request

the

Z80

to

sus.pend

activity

and

allow

direct

memory

access

by

a

peripheral

d'evice.

Interrupt

request

line

to

the

Z80

from

the

on-

board

vectored

interrupt

logic

or

from

some

other

board.

This

signal

("interrupts

enabled"

on

8080

systems)

is

normally

true

tiut

goes

false

momentarily

during

interrupt

acknowledge

sequences

thus

providing

an

edge

to

latch

the

VI

lines

for

boards

such

as

the

IMSAI

PIC-8.

Memory

cycle

request

signal

from

the

Z80.

Non-maskable

interrupt

request

to

Z80.

System

reset

synchronized

to

the

Z80

clock.

True

when

the

RESET

switch

is

depressed

or

momentarily

when

power

first

comes

on.

When

false,

causes

the

Z80

to

WAIT.

Usually

generated

by memory

boards

to'

extend

memory

cycles

for

slow

access

time

memories.

See

'also

XRDY.

North

Star

Z80A

PROCESSOR

BOARD

24

75 PRESET/

66 PRFSH/

76

PSYNC

27

PWAIT

77

PWR/

71

RUN

48

SHLTA

46 SINP

96

SINTA

47

SMEMR

44

SMI

45

SOUT

21

SS

98

SSTACK

53

SSW-DSBL

18 STA-DSBL/

97

SWO

03

XRDY

DATA

BUS

connected

to

the

reset

switch.

Dynamic memory

refresh

signal

generated

by

the

Z80.

This

signal

is

true

between

memory

and/or

IO

cycles

of

the

Z80.

Usually

one

clock

cycle

wide

(sometimes

two).

Usually

used

by

wait

state

counters

on memory

boards.

True

when

the

Z80

is

in

the

wait

state

caused

by

PRDY

or

XRDY.

Timing"

sign~l

generated

during

memory

write

and

output

operations

which

indicates

that

valid

data

is

on

the

DO

bus.

Signal

generated

by

a

control

panel

to

indicate

the

processor

should

be

in

run

mode

True

if

theZ80

is

executing

a

halt

instruction.

True

during

an

input

operation.

True

during

an

interrupt

qcknowledge

operation.

True

during

a memory

read

operation~

True

during

the

i~struGtion

opcode

fetch

portion

of

each

instruction

cycle

of

the

Z80.

For

instructions

with

two

opcode

bytes,

this

signal

is

true

twi~e.

,_;.~.

True

durlpg

output

operatlons.

Generated

by

a

control

panel

to

indicate

that

the

Z80

should

be

in

run

mode

during

a

single

step

operation.

Always

false.

On

8080

systems

indicates

that

a

stack

reference

cycle

is

in

progress.

DisablesDI

bus

receivers

and"

enables

CP

bus

receivers.

Used

during

input

of

sense

"switches

from

a

control

panel.

Disables

drivers

for

SMEMR,

SWO,

SINP,

SHLTA,

SMl,

SOUT,

and

SINTA.

True

when

the

Z80

is

sending

data

out

on

the

DO

bus.

Causes

the

Z80

to

enter

~ait

mode when

false.

Usually

generated

by

a

control

panel

to

cause

a

control

panel

stop.

There

has

been

some

conflict

of

use

between

this

signal

and

PRDY

so

care

should

be

taken

to

guarantee

that

drivers

on

this

line

from

different

boards

cannot

be

simultaneously

active.

NOTE:

This

and

the

following

sections

will

be

more

meaningful

if

the

schematic

drawings

are

referenced

while

they

are

read.

The

capitalized

signal

names

refer

to

names

used

in

the

drawings.

The

Z80

data

bus

(ZD0-ZD7)

is

the

8

data

bits

directly

connected

to

the

Z80

processor.

The

data

bus

from

the

control

panel

(CP0-

CP7)

is

gated

onto

the

ZD

bus

by

the

CPIN-EN

signal

during

control

panel

operations.

The

S-100

data

input

bus

(DI0-DI7)

is

25

North

Star

Z80A

PROCESSOR

BOARD

)

gated

onto

the

ZD

bus

by

the

DI-EN

signal

during

Z80

read

operations

(RD-D)

except

on-board

PROM

reads

and

during

interrupt

operations

(XINTA).

The

ZD

bus

is

gated

onto

the

control

panel

bus

whenever

a

control

panel

operation

is

not

in

progress.

The

ZD

bus

is

gated

onto

the

S-100

data

output

bus

(D00-D07)'

b'y DO-EN

during

memory

write

and

output

operations

of

the

Z80.

The

data

from

the

on-board

PROM

is

gated

onto

the

ZD

bus

directly

by

the

PROM-EN

signal

during

on-board

PROM

read

operations.

ADDRESS

BUS

The

sixteen

address

lines

from

the

Z80

(ZA0-ZA15)

are

connected

through

drivers

to

the

S-100

address

bus

(A0-A15)

except

during

input/output

operations.

In

this

latter

case"if

the

address

mirroring

feature

is

enabled

then

the

low

order

8

address

bits

from

the

Z80

are

gated

onto

both

the

top

and

bottom

8

blts

of

the

S~100

address

bus.

This

feature

allows

simulation

of

8080

I/O

operations

for

systems

that

include

S-100

boards

that

take

advantage

of

this

8080

characteristic

•.

VECTORED

INTERRUPTS

The

on-board

vectored

interrupt

capability

provides

for

a

priority

response

to

8

interrupt

levels.

Whenever

the

Z80

generates

an

interrupt

acknowledge

condition

(INTA),

the

state

of

the

eight

interrupt

request

lines

(VI0-VI7)

is

latched

(8B,

8C)

and

the

latch

outputs

are

fed

to

a

priority

encoder

(8D).

The

~hree

encoder

outputs

indicate

the

highest

priority

pending

interrupt

re~uest.

These

lines

are

merged

with

"1"

bits

at

the

multiplexors

(2D,

IE)

to

provide

the

correct

RST

instruction

on

the

Z80

data

bus

(ZD0-ZD7)

when

the

multiplexor

is

enabled

by

MX-

EN.

The

INT-RQ

signal

out

of

the

encoder

indicates

that

at

least

,one

interrupt

request

level

is

pending

and

causes

an

interrupt

request

to

the

Z80

if

on-board

interrupts

are

enabled

(OBIE).

AUTO-JUMP

The

auto-jump

feature

causes

an

automatic

jump

to

a

jumper-wire-

specified

address

(2E)

upon

power-on

or

reset.

The

register

at

4G

is

configured

to

be

a

four

state

counter.

The

restart

condition

(RST)

resets

the

register

and

each

successive

read

cycle

(RD)

causes

the

register

to

shift

to

the

until

the

auto-jump

sequence

is

done

in

the

fourth

state

(AUJ-DONE).

The

first

three

states

cause

the

three

bytes

of

an

unconditional

jump

instruction

to

the

specified

address

to

be

multiplexed

(IE,

2D)

onto

the

Z80

data

bus

(ZD0-ZD7).

The

AUJ-DONE

signal

disables

the

auto-jump

feature

until

the

condition

reinitiates

the

entire

sequence.

The

AUJS

signal

causes

the

two

address

bytes

to

be

selected

by

the

multiplexors

(IE,

2D)

during

the

second

and

third

states.

The

jump

opcode

is

generated

during

the

first

state

as

a

special

case

of

the

interrupt

logic

which

generates

a JMP

instruction

rather

than

an

RST.

North

Star

Z80A PROCESSOR

BOARD

26

The

auto-jump

feature

can

be

disabled

by

removing

the

74LSl75

chip

from

location

4G.

ON-BOARD

PROM

OPTION

The

ZPB

has

provision

for

one

on-board

2708

type

EPROM.

The

PROM

address

can

be

specified

by

jumper

wire

selection

(5E)

to

start

on

any

lK

address

boundary.

The

address

comparison

to

test

for

on-board

PROM

addresses

is

performed

by

the

exclusive-or

gates

(5C,

5D)

The

PROM

is

enabled

(PROM-EN)

if

the

high

order

6

address

bits

compare

during

a

memory

read

operation.

A

wait.

state

is

provided

for

the

PROM

so

that

the

r~st

of

memory

may

run

at

full

speed.

27

North

Star

Z80A PROCESSOR

BOARD

APPENDIX

1.

PULSE

SIGNAL

DETECTION

Some

steps

in

the

checkout

procedure

will

require

test

equipment

capable

of

distinguishing

a

signal

containing

pulses

from

a

DC

signal.

Anyone

of

the

following

will

suffice.

1.

Use

of

an

oscilloscope

is

best

since

the

shape

and

frequency

of

the

pulses

can

also

be

determined.

2.

Use a

logic

probe

that

detects

pulses.

3.

If

the

ZPB

is

being

assembled

for

use

with

a

HORIZON,

then

use

a

counter

on

the

motherboard

to

divide

the

frequencies

down

to

the

audio

range

and

then

play

the

result

through

a

hi-fi

amplifier.

To

do

this,

remove

the

74LS161

at

location

7D

on

the

motherboard.

Then

attach

the

test

probe

wire

to

jumper

2D

16

(this

is

the

input

to

the

divider).

Next,

take

the

output

of

the

divider

at

jumper

10A

11

and

connect

to

the

AUX

input

of

the

audio

amplifier.

Finally,

connect

the

AUX

input

ground

on

the

audio

amplifier

to

signal

ground

on

the

motherboard.

This

arrangement

will

divide

high

frequency

signals

by 4096

and

thus

put

the

resulting

signal

in

the

audible

range.

Thus

a 4

MHz

signal

will

be

heard

as

a

tone

one

octave

higher

than

a

2MHz

signal.

4.

Construct

the

"probe"

shown

in

figure

lC

on

a

piece

of

cardboard

or

perf-board.

This

probe

converts

high

frequency

signals

to

DC

signals.

The

voltage

of

the

resulting

DC

signal

will

be

proportional

to

the

duty

factor

of

the

tested

wave

form.

North

Star

Z80A

PROCESSOR

BOARD

28

APPENDIX

2.

S-100

BUS

SIGNALS

# SIGNAL

1 +8

VOLTS

51

+8

VOLTS

2

+16

VOLTS

52

-16

VOLTS

3

XRDY

53 SSW-DSBL/

4

VI0/

54

EXT-CLR/

5

VII/

55

6

VI2/

56

7

VI3/

57

8

VI4/

58

9

VIS/

59

10

VI6/

60

11

VI7/

61

GROUND

(optional)

12

62

13

63

14

64

15

65 PMREQ/

16

66

PRFSH/

17

67

PHANTOM

18

STA-DSBL/ 68

MWRITE

19

CC-DSBL/

69

PSI

20

GROUND

(optional)

70

GROUND

(optional)

21 SS 71

RUN

22

ADDR-DSBL/ 72

PRDY

23 DO-DSBL/ 73

PINT/

24 PHI 2 74 PHOLD/

25 PHI 1 75

PRESET/

26

PHLDA

76

PSYNC

27

PWAIT

77

PWR/

28 PINTE 78 PDBIN

29

AS,

79

A0

30

A4

80

Al

31 AJ: 81 A2·

32

AIS

82

A6'

33

A12

83

A7'

34

A9

84

A8

.

3~

001

85

A13

36

00,0 86 A14

37

A10

87

All

DO"l...

38

004

88

~

39

DOS

89 D03

40

D06

90

D07

41

012

91

DI4

42

013

92

DIS

43

017

93

DI6

44

SM1

94

DI1

45

SOUT

95

010

46

SINP

I

96

SINTA

47

SMEMR

97

SWO

48

SHLTA

98

SSTACK

49

2MHZ

CLOCK/

99

POC/

50

GROUND

100

GROUND

29

North

Star

Z80A PROCESSOR

BOARD

SOURCE

OF

ONES

IN

80TH

BYTES

~======jfr;:~

SOLJRCf:

OF

ONES.

IN

HI

BYT E I

..

.

-=======:f:l

ZEROES

IN

LO

BYTE

5

SOURCE

OF

ZEROES

IN

HI

BYTE?

"~=====::::J

BIT

7

ilT

,

SIT

S

BIT

+

BIT

3

81

T

2-

BIT

I

BIT

q>

i:iATED

TO

DATA BUs

DURINg

.AUJ

SEG/UE:NCE

SOURC.E

OF

ONES

IN

LO

8YT

E I

ZEROES

IN

BOTH

BYTES

-======:::::JQ!;L'='-g

o

FtP¢C

FI~()RE

I

Z:

AUJ

(POJ)

ADDRESS

HEADER

(LOCATiON

2.E))

WITH

THREE

EXAMPLES.

LOGIC.

LEVEL

WHICH

_=======~

MATCHES ZEROES

1..0",C.

I..EVEL

WHICH

MATCHES

ONES

o o

BITI5"j

BIT

14

BIT

13

81

T

IZ

Blr

II

BI

r

14>

o o

FROM

CPU

~

ZAIS"

ZAI4

ZAI3

ZAI2.

ZAII

zAIIP

MATCH

o

c

o

5C,D

o

f:,C,URE I

P:

PROM

ADDRESS

HEADER

(LOCATION

5E)J

WITH

THREE

EXAMPLES.

I'

--

-

--

------- -

-,

I

"-

I

f-

a

I

1.2.K

47tiJpF IN4148 1 I

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ZPB

SIGNAL

(,ROUND

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S\G.NAL

DETEC.TOR

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DISABLES

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North_Star_Z80A_Processor_Board_ZPB A_Rev_2_1977 North Star Z80A Processor Board ZPB A Rev 2 1977

North_Star_Z80A_Processor_Board_ZPB-A_Rev_2_1977 North_Star_Z80A_Processor_Board_ZPB-A_Rev_2_1977

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