Ampro Little board/plus User manual

COMPUTERS,

INCORPORATED

LITTLE BOARD/PLUS

TECHNICAL

MANUAL

Part

Number:

A74010

Revision: B

67

East

Evelyn

Ave

.•

Mountain

View,

CA

94041

• (415)962-0230

PREFACE

This

manual

is

for

integrators

of

systems

based

on

Little

Board/PLUS.

It

contains

information

on

hardware

requirements

and

interconnection,

and

details

of

how

to

use

the

system.

There

are

five

chapters,

organized

as

follows:

Chapterl-

GENERAL

DESCRIPTION:

General

information

pertaining

to

the

Little

Board/PLUS,

its

major

features,

and

a

brief

functional

description

of

the

board.

Chapter

2 - INTEGRATING A SYSTEM:

Descriptions

of

the

external

components

necessary

to

construct

a

CP/M-based

system

with

floppy

and

hard

disk

drives.

Included

are

tables

listing

the

pinouts

of

each

of

the

six

board

connectors,

as

well

as

features

and

special

considerations

concerning

the

board's

peripheral

interfaces.

Chapter

3 -

USING

THE SYSTEM:

System

power-up

procedures,

and

operation

with

AMPRO's

enhanced

CP/M

operating

system

and

utilities.

Chapter

4 -

THEORY

OF

OPERATION:

Detailed

technical

information

on

Little

Board/PLUS

hardware.

Chapter

5 -

PROGRAMMER'S

REFERENCE:

I/O

port

addresses

and

programming

information

regarding

custom

programming

of

Little

Board/PLUS.

Only

brief

descriptions

and

instructions

regarding

the

Little

Board/PLUS

system

software

are

provided

in

this

manual.

For

full

details

on

the

AMPRO-

supplied

system

software,

please

refer

to

the

Z80

System

Software

User's

Manual

(AMPRO

part

number

A74006).

PLEASE NOTE

Specifications

are

subject

to

change

without

notice.

The

contents

of

this

document

are

believed

to

be

accurate.

If

errors

are

found,

please

notify

AMPRO

COMPUTERS INC.,

at

the

address

shown

on

the

title

page

of

this

document.

The

following

is

a

list

of

trademarks

used

within

this

document:

Z80: Zilog,

Inc.

CP/M:

Digital

Research,

Inc.

mM:

International

Business

Machines

ZCPR3:

Richard

L.

Conn

LITTLE

BOARD,

LITTLE Board/PLUS, SCSI/PLUS:

AMPRO

Computers,

Inc.

No

part

of

this

document

may

be

reproduced

in

any

form,

for

commercial

purposes

without

the

express

written

consent

of

AM

PRO

Computers,

Inc.

Copyright

(C)

1985,

A.PRO

COMPUTERS INCORPORATED

TABLE OF

CONTENTS

CHAPTER 1 - GENERAL DESCRIPTION

1.1

Introduction

1.2

Features

1.3

Functional

Description

1.3.1

CPU,

Memory,

and

Timing

1.3.2

Serial

I/O

Ports

1.3.3

Parallel

I/O

Port

1.3.4

Floppy

Disk

Controller

1.3.5

SCSI/PLUS

Multi-Master

Bus

1.4

Specifications

CHAPTER

2 -

INTEGRATING

A SYSTEM

2.1

Introduction

2.2

What

Is

Needed

2.2.1

DC

Power

2.2.2

Reset,

Power

LED

2.2.3

Parallel

Printer

2.2.4

Serial

Ports

2.2.5

Floppy

Disk

Interface

2.2.6

SCSI/PLUS

Interface

2.2.7

ID

Input

Port

2.3

Board

Jumper

Configurations

2.4

Booting

the

System

2.5

Troubleshooting

CHAPTER

3 - USING THE SYSTEM

3.1

Introduction

3.1.1

Software

References

3.1.2

Conventions

3.2

First

Time

Use

3.2.1

Making

Backup

Disks

3.2.2

Customizing

Your

System

Disk

3.3

Operating

System

Features

3.3.1

CP/M

2.2

BDOS

3.3.2

AMPRO

Custom

BIOS

3.3.3

ZCPR3

Command

Processor

3.4

AMPRO-Supplied

Utilities

3.4.1

CP/M

Utilitiy

Programs

3.4.2

AMPRO

Utilities

3.4.3

ZCPR3

Utilities

3.4.4

Public

Domain

Programs

3.5

Generating

Different

Systems

CHAPTER

4 - THEORY OF OPERATION

4.1

Introduction

4.2

CPU,

Memory,

and

Timing

4.3

Board

Control

Register

4.4

Serial

Ports

4.5

Parallel

Printer

Port

4.6

Floppy

Disk

Interface

4.7

SCSI/PLUS

lnterface

1-1

1-2

1-3

1-4

2-1

2-3

2-4

2-5

2-7

2-8

3-1

3-2

3-3

3-4

3-5

3-8

3-9

3-10

3-11

4-1

4-2

4-3

4-4

CHAPTER

5 - PROGRAMMERS' REFERENCE

5.1

Introduction

5.2

ZSOA

CPU

5.3

Memory

5.4

Board

Control

Register

5.5

Counter/Timer

Circuit

5.6

Serial

Ports

5.7

Baud

Rate

Generation

5.S

Floppy

Disk

Interface

5.9

Parallel

Printer

Port

5.10

ID

Input

Port

5.11

SCSI/PLUS

Interface

5.11.1

SCSI (SASI)

Programming

5.11.2

Simple

Bidirectional

I/O

5-1

5-2

5-3

5-4

5-5

5-6

5-7

APPENDIX

A - BOARD

DIAGRAM,

PARTS

LIST,

AND

SCHEMATIC

APPENDIX

B -

TYPICAL

INTERFACE

CABLES

APPENDIX

C -

USER

GROUPS

ApPENDIX

D - COMPONENT

DATA

SHEETS

CHAPTER

1

GENERAL

DESCRIPTION

1.1

INTRODUCTION

This

chapter

provides

an

overview

and

functional

description

of

the

AMPRO

Little

Board/PLUS

single

board

computer.

It

is

intended

to

provide

a

basic

understanding

of

the

Little

Board/PLUS,

and

how

it

forms

the

basis

of

a

compact,

powerful

computer

system.

1.2

FEATURES

Little

Board/PLUS

is

a

complete

8-bit,

Z80-based

single

board

microcomputer.

It

includes

all

the

circuitry,

software,

and

firmware

necessary

to

construct

a

functional

CP/M-based

computer

system.

Some

of

the

main

features

are:

.4MHz

Z80A

8-bit

microprocessor

• 64K

bytes

dynamic

RAM,

4K

-32K

EPROM

•

Two

spare

counter/timer

channels

• Floppy

controller

capable

of

controlling

from

one

to

four

single-

or

doubl~-sided,

single-

or

double-density,

40-

or

80-track

mini

or

micro

floppy

drives

•

Two

RS232C

serial

ports

•

One

Centronics

printer

port

• SCSI/PLUS

multi-master

I/O

expansion

bus:

• SASI

Disk/Tape

controller

compatible

•

ANSC

X3T9.2 (SCSI)

compatible

•

Multiple

Little

Board

networking

•

Simple

bi-directional

I/O (17

lines)

• Mounts

directly

to

a

5-1/4"

disk

drive

• Minimum

external

components

•

Power

connector

and

voltages

compatible

with

5-1/4

inch

disk

drives

1.3

FUNCTIONAL

DESCRIPTION

The

following

paragraphs

briefly

describe

the

Little

Board/PLUS

single

board

computer.

More

detailed

information

can

be

found

,in

Chapter

4,

Theory

of

Operation.

1-1

1.3.1

CPU,

Memory,

and

Timing

The

heart

of

the

Little

Board/PLUS

is

a Z80A

8-bit

microprocessor

operating

at

4 MHz. All

system

functions

are

based

on

a

single

16

MHz

master

clock.

System

RESET

is

provided

in

two

ways:

upon

power-up

and

via

an

external

RESET

switch.

Two

types

of

memory

are

present:

EPROM

and

RAM.

A

single

28-pin

EPROM

socket

provides

from

4K

to

32K

bytes

of

firmware

space.

Jumpers

are

used

to

program

the

socket

for

a

2732,

2764,

27128,

or

27256

type

EPROM.

The

EPROM

can

be

enabled

and

disabled

by

software.

System

RAM

consists

of

eight

64k

x 1

bit

dynamic

RAM

devices.

Control

circui-

try

for

the

RAM

memory

is

entirely

digital

(no

one-shots

or

R-C

components)

and

provides

a

high

degree

of

reliability.

A

ZSO

Counter

Timer

Circuit

(CTC)

provides

four

programmable

counter

or

timer

channels.

Two

of

the

CTC

channels

provide

the

baud

rate

clocks

used

by

the

two

serial

I/O

ports.

The

other

two

CTC

channels

are

available

for

use

as

programmable

timers

in

applications

programs,

for

real-time

clock

functions,

etc.

1.3.2

Serial

Ports

A Z-SO

Dual

Asynchronous

Receiver/Transmitter

(DART)

provides

two

fully

pro-

grammable

serial

I/O

ports.

Each

channel

has

four

of

the

standard

RS232C

signals:

TxD, RxD, RTS,

and

CTS.

These

signals

are

sufficient

for

interfacing

most

serial

printers,

modems,

and

terminals.

In

those

cases

where

other

interface

signals

are

required

for

one

of

the

serial

ports,

handshaking

·signals

can

be

borrowed

from

the

second

port

(if

not

needed

by

that

port).

Polarity

and

use

of

the

handshaking

signals

is

defined

by

the

software.

Programmable

baud

rate

clocks

are

supplied

by

the

CTC

for

baud

rates

up

to

9600

baud.

Additional

circuitry

provides

baud

rates

of

19.2K

and

3S.4K

baud,

for

Port

A

only.

Since

the

two

serial

ports

are

otherwise

identical,

either

can

be

programmed

as

a

terminal,

modem,

serial

printer,

or

other

RS232C

inter-

face.

1.3.3

Parallel

Printer

Port

The

parallel

printer

port

provides

the

10

essential

signals

of

a

Centronics-

type

printer

interface:

Data

Bits

I-S,

Data

Strobe,

and

Busy.

Both

the

Data

Strobe

(output)

and

Busy

(input)

handshake

protocols

are

defined

by

software.

1.3.4

Floppy

Disk

Controller

A

Western

Digital

1772

floppy

disk

controller

device

provides

all

of

the

functions

required

to

interface

with

standard

5-1/4

inch

"mini"

--

and

most

3

to

4

inch

"micro"

--

floppy

disk

drives.

The

1772

includes

the

following

capabilities

within

a

single

LSI

device:

1-2

•

Digital

phase

locked

loop

•

Digital

write

precompensation

•

Motor

on

start/stop

delay

•

Software

controlled

step

rates

Timing

for

the

floppy

disk

interface

is

derived

directly

from

the

8

MHz

system

.

clock,

without

delay

lines,

R-C

time

constants,

or

one-shots.

This

again

results

in

a

very

high

degree

of

system

reliability.

1.3.5

SCSI/PLUS

Multi-Master

Bus

A

50-pin

"ribbon

cable

bus"

interface

which

meets

the

specifications

for

the

popular

Small

Computer

System

Interfaces

(SCSI)

--

formerly

called

"SASI"

--

provides

a

general

purpose

multi-master

I/O

expansion

bus.

All SCSI

Initiator

and

Target

functions

are

fully

supported,

including

bus

arbitration

and

dis-

.

connect/reselect.

In

addition,

Little

Board/PLUS

supports

the

Initiator

function

of

AMPRO's

innovative

SCSI/PLUS

extension

to

SCSI.

This

allows

connection

of

up

to

64

SCSI/PLUS

Target

devices,

rather

than

the

usual

eight

device

limit

of

SCSI.

Applications

include

both

direct

and

shared

use

of

a

wide

variety

of

control-

lers

and

devices,

as

well

as

tightly

coupled

Little

Board

networks.

For

example,

one

or

more

Little

Boards,

an

SCSI

Winchester

controller,

and

modules

providing

calendar/clock,

serial

port

expansion,

RAM

disk,

etc.,

might

all

coexist

on

the

same

SCSI/PLUS

bus.

The

17

bidirectional

I/O

signals

of

the

SCSI/PLUS

interface

may

also

be

used

as

general

purpose

software-controlled

digital

I/O

lines,

without

SCSI

compa-

tibility.

In

this

case

the

board's

8-bit

SCSI

bus

ID

input

register

can

serve

as

an

additional

8-bit

input

port.

1-3

1.4

LITTLE BOARD/PLUS SPECIFICATIONS

CPU:

MEMORY:

TIMER:

SERIAL

I/O:

4MHz Z80A,

8-bit

microprocessor

64

kilobytes

of

dynamic

RAM

4-32

kilobytes

of

EPROM

Z80A CTC (4

channels)

2

channels

not

used

by

AMPRO

software

Z80A

Dual

Asynchronous

Receiver/Transmitter

(DART)

Two

-RS232C

compatible

ports:

DB-25

female

conns.

Software-controlled

baud

rates:

Channel

A - 75

to

38,400

baud

Channel

B - 75

to

9600

baud

Four

standard

RS232C

signals

per

port:

Data

Out

Data

In

Handshake

Out

Handshake

In

Two

Ground

pins

PARALLEL

I/O:

Centronics-compatible

printer

port

10

signals

supported:

Data

Bits

1-8

-

output

Data

Strobe

-

output

Printer

Busy -

input

12

Ground

pins

DISK

I/O:

No.

drives

supported:

1 - 4

Disk

Controller:

WD1772

Data

rate:

250k

bps

(MFM), 125K

bps

(FM)

Sector

size:

128,

256,

512,

or

1024

bytes

Phase

locked

loop:

digital

(8 mHz)

Write

precompensation:

software

enabled

Drive

capacity

(formatted):

SCSI/PLUS

BUS

INTERFACE:

Type

1 (40

track,

1-sided)

-200K

bytes

Type

2 (40

track,

2-sided)

-400K

bytes

Type

3 (80

track,

1-sided)

-400K

bytes

Type

4 (80

track,

2-sided)

-800K

bytes

SASI

Compatible

ANSI

X3T9.2

(SCSI)

compatible

SCSI/PLUS

Initiator

compatible

Uses

NCR

5380

SCSI

bus

controller

POWER:

Same

power

connector

and

voltabes

as

mini

and

micro

floppy

disk

drives.

Power

Requirements:

+5VDC

at

O.95A

+9

to

12VDC

at

0.05A

ENVIRONMENT:

Temperature:

0

to

32

degrees

C,

operating

Humidity:

5

to

9596,

non-condensing

Altitude:

0-10,000

feet

1-4

SIZE: '

SOFTWARE:

7.75 x

5.75

x

0.75

inches

Boot

program

in

2732

EPROM

CP/M

Version

2.2

and

BIOS

on

diskette

Little

Board/Plus

system

utilities

Option:

FRIENDLY

Integrated

Operating

Environment

Option:

BIOS

and

Utilities

source

code

DOCUMENTATION:

Little

Board/Plus

Technical

Manual

Little

Board/Plus

Software

Manual

Option:

SCSI/PLUS

Technical

Specification

1-5

CHAPTER

2

INTEGRA

TING

A

SYSTEM

2.1

INTRODUCTION

This

chapter

describes

what

is

required

to

build

a

floppy

or

hard

disk

based

computer

system

using

Little

Board/PLUS

as

the

heart

of

the

machine.

Details

are

provided

concerning

external

device

requirements,

the

boards

connector

pinouts,

how

to

prepare

the

board

for

use,

and

connection

of

peripherals

such

as

terminals,

printers,

and

modems.

Refer

to

Appendix

B

for

tables.

2.2

WHAT

IS

NEEDED

A

very

minimum

number

of

external

parts

will

turn

the

Little

Board/PLUS

circuit

board

into

a

very

powerful

computer

system.

The

items

listed

in

Table

2-1

are

easily

available

components.

Item

Floppy

drive(s)

SCSI (SASI)

hard

disk

controller

(option)

Hard

disk

drive(s)

(option)

Power

supply

Reset

switch

Cables

Cabinet

Table

2-1.

System

Components

Description

1

to

4 mini

or

micro

floppy

drives,

40

or

80

track,

single-

or

double-sided

Adaptec

ACB-4000

or

Xebec

1410(A),

or

equivalent

SCSI (SASI)

hard

disk

controller

5

to

20

Megabyte

drive(s);

must

be

compatible

with

your

specific

SCSI (SASI)

controller

+12VDC @ 2.0A,

+5

VDC

@ 2.5A (2

floppies);

additional

power,

as

required

for

hard

disk

options

SPST,

normally

open,

w/LED

indicator

Serial

(2),

parallel,

floppy,

SCSI,

and

power

cables

for

Little

Board/PLUS

and

drives

Housing

for

completed

system

Figure

2-1

shows

the

Little

Board/PLUS

interface

connectors.

All

components

can

be

housed

in

a

very

small

box.

The

size

is

determined

primarily

by

the

disk

drives,

and

perhaps

the

power

supply.

A

space

of

approximately

7 x 8 x

11

inches

is

adequate

for

a

dual

floppy

system.

Tables

2-2

through

2-7

list

the

cable

connector

pinouts

for

the

board's

interface

connectors.

Table

2-2

provides

suggested

mating

connectors

and

manufacturers'

part

numbers.

2-1

Table

2-2.

External

Connector

Part

Numbers

Board

Function

Part

Number

Connector

J1

Power

Connector

Housing:

AMP

1-480424-0

Contacts:

AMP

60619-1

(4

req.)

J2

Parallel

Printer,

3M:

3399-6000

Board

end

T&B:

609-2601M

Molex:

15-29-8262

Parallel

Printer,

AMP:

57F-30360

Printer

end

3M:

3366-1001

T&B:

609-36M

J3,4

Serial

Ports

A,B

Housing:

Molex

22-01-2067

Contacts:

Molex

08-50-0114

(6

req.)

J5

RESET,

Power

LED

Housing:

Molex

22-01-2047

Contacts:

Molex

08-50-0114

(4

req.)

J6

Floppy

Disk

Interface

3M:

3463-0001

(Card

edge

connectors)

T&B:

609-3415M

Molex:

15-29-0341

J8

SCSI/PLUS

Interface

T&B:

609-5000M

Molex:

15-29-8502

Berg:

66902-150

NOTE

All

Little

Board/PLUS

s,oftware

is

distributed

on

double-

sided

48

tpi

AMPRO

format

mini

floppy

diskettes.

This

may

be

directly

read

from,

or

booted,

in

either

a

48

or

96

tpi

mini

floppy

drive.

The

only

special

requirement

for

first

time

booting

of

the

system

is

that

you

have

a

double-sided

48

or

96

tpi

mini

floppy

drive

capable

of

stepping

at

a 6

mS

step

rate,

and

a

terminal

capable

of

9600

baud

opera-

tion.

Once

you

have

initially

booted

the

system,

you

may

then

generate

a

system

disk

with

alternative

defaults,

e.g.,

single-sided,

micro

floppy,

12

mS

step

rate,

19.2K

baud

terminal

data'

rate,

etc.

2-2

PARALLEL PRINTER

J

.0

---POWER

o

•

~~---

SERIAL A

SERIAL B

~-+----

RESET. POWER LED

-

...

---

FLOPPY

'-----

m

INPUT

Figure

2-1.

Little

Board/PLUS

Connector

Locations.

2-3

2.2.1

DC

Power

The

power

connector

(Jl)

pinout

is

identical

with

that

of

the

power

connectors

on

nearly

all

5

-1/4

inch

floppy

disk

drives.

Note

that

1

on

Jl

is

reversed

from

the

other

connectors

on

the

same

end

of

the

board.

Refer

to

Table

2-3

for

power

connections.

CAUTION

BE

SURE

THE

POWER

PLUG

IS

CORRECTLY

WIRED

BEFORE

ATTEMPTING TO APPLY

POWER

TO

THE BOARD.

Table

2-3.

Power

Connections

(.11)

Signal

Name

Function

1 +12VDC

+6

to

+ 15VDC

2

Ground

return

3

Ground Ground

return

4 +5VDC +5VDC

+/-

5%

2.2.2

RESET,

Power

LED

This

connector

is

for

connection

to

an

external

SPST

switch,

to

provide

the

master

RESET

signal.

In

addition,

a 15

rnA

current

source

provides

power

to

an

LED

power-on

indicator.

Refer

to

Table

2-4

for

the

pinout

of

connector

J5.

Table

2-4.

RESET,

Power

LED

Connector

(.15)

Signal

Name

Function

1

Ground

To

LED

Cathode

2

LED

To

LED

Anode

3

Ground

To

one

side

of

RESET

switch

4 RESET To

other

side

of

RESET

switch

2.2.3

Serial

Ports

Table

2-5

lists

the

connector

pinout

and

signal

definitions

for

each

of

the

two

RS232C

serial

I/O

ports.

Serial

Port

A

is

board

connector

J3,

and

Serial

Port

B

is

board

connector

J4.

Appendix

B

gives

typical

cable

wiring

for

connection

to

terminals,

serial

printers,

and

modems.

2-4

Table

2-5.

Serial

Connectors

(.13/.14)

Signal

Name

Function

in/out

DB-25

(DCE)

1

Ground

Protective

Ground

--

1

2

Ground

Signal

Ground

--

7

3 TxD

Data

Output

out

3

4

HSO

Hand

Shake

Out

(RTS)

out

5

5 RxD

Data

Input

in

2

6 IISI

Hand

Shake

In (CTS)

in

20

2.2.4

Parallel

Printer

The

Little

Board/PLUS

parallel

printer connector

has

a

pinout

that

allows

the

use

of

flat

ribbon

cable

between

the

J2

header

and

the

first

26

lines

of

a 36

male

Centronics-type

connector

at

the

printer

end.

Refer

to

Table

2-6

for

the

printer

connector's

pinout

and

signal

definitions.

Note

that

the

numbering

convention

for

the

board's

header

connector

(J2)

differs

from

that

of

Centronics

connectors,

even

though

the

required

inter-

connection

cable

is

straight

through.

To

clarify

this,

each

signal's

corres-

ponding

Centronics

connector

number

has

been

included

in

Table

2-6.

Table

2-6.

Parallel

Printer

Connector

(.12)

J2

Signal

Name

Function

in/out

Printer

Pin Pin

1 -DS

Data

Strobe

out

1

3

Data

1

LSB

of

printer

data

out

2

5

Data

2 · · 3

· ·

7

Data

3 · · 4

· ·

9

Data

4 · · 5

· ·

11

Data

5 · · 6

· ·

13

Data

6 · · 7

· ·

15

Data

7 · · 8

· ·

.17

Data

8

MSB

of

printer

data

out

9

19

---

(Not

used)

21

BUSY

Printer

BUSY

in

11

23

---

(Not

used)

25

---

(Not

used)

2-22

(even)

Signal

grounds

19-29

24,26

---

(Not

used)

30,31

Appendix

8

provides

a

wlrmg

table

for

a

cable

which

will

work

with

most

Centronics

compatible

printers.

The

cable

required

is

identical

to

that

used

with

the

Tandy

(Radio

Shack)

TRS-80

Model

100

portable

computer.

The

Tandy

cable

part

number

is

26-1409.

2-5

2.2.5

Floppy

Disk

Interface

Table

2-7

lists

the

Goppy

disk

drive

interface

connector

(J6)

pinout

and

signals.

A

single

34-conductor

PC

edgecard

connector

goes

at

the

Little

Board

end,

while

there

can

be

from

1

to

4

PC

card

edge

connectors

for

connecting

mini

floppy

disk

drives.

Micro

Goppy

drives

generally

use

34-conductor

header

connectors,

instead.

Table

2-7.

Floppy

Disk

Interface

Connector

("'6)

Signal

Name

Function

in/out

2

-LOW

SPEED

Speed

select

(option)

out

4

---

(Not

used)

--

6 -DRIVE

DEL

4

Drive

Select

4

out

8 -INDEX

Index

pulse

in

10

-DRIVE

SEL

1

Drive

Select

1

out

12

-DRIVE

SEL

2

Drive

Select

2

out

14

-DRIVE

SEL

3

Drive

Select

3

out

16

-MOTOR

ON

Motor

on

control

out

18

-DIR

SEL

Direction

select

out

20

-STEP

Step

out

22 -WRITE DATA

Write

data

out

24 -WRITE GATE

Write

gate

control

out

26

-TRACK 00

Track

00

in

28

-WRITE PRT

Write

protect

in

30

-READ DATA

Read

data

in

32 -SIDE

ONE

Side

select

out

34 -READY

Drive

ready

(option)

in

1-33

(all

odd

pins)

Signal

grounds

--

Nearly

any

type

of

soft-sectored,

single-

or

double-sided,

40-

or

80-track,

mini

(5

1/4")

or

micro

(3"

to

4")

floppy

disk

drive

is

usable

with

the

Little

Board.

Naturally,

the

higher

the

quality

of

the

drives

you

use,

the

better

your

system's

reliability.

Here

are

some

things

that

may

be

helpful

for

you

to

know:

•

As

indicated

earlier

in

this

chapter,the

default

system

parameters

programmed

on

the

standard

Little

Board/PLUS

system

disk,

as

shipped,

require

that

drive

A

be

a

double-sided

48

or

96

tpi

mini

floppy

drive,

with

6

mS

(or

faster)

stepping

rate.

Once

you

have

booted

that

disk,

you

can

create

a

new

system

disk

with

alternative

defaults,

allowing

you

to

subsequently

boot

from

any

other

system-compatible

drive.

•

The

drives

used

must

be

compatible

with

the

AMPRO

floppy

disk

inter-

face

(see

Table

2-7).

This

interface

is

generally

referred

to

as

SA-

450

compatible.

• Use

of

high

quality

floppy

disk

drives

is

recommended;

preferably

having

DC

servo-controlled

direct

drive

motors.

•

The

drives

must

be

capable

of

12

mS

(or

faster)

stepping.

2-6

• More

than

one

type

of

floppy

disk

drive,

up

to

four,

can

be

present

in

the

system,

and

in

any

mix.

•

Each

disk

drive

must

be

jumpered

for

a

specific

Drive

Select

value,

1

through

4.

Drive

A

is

1,

B

is

2,

etc.

•

Resistive

terminations

should

be

installed

only

on

the

drive

connected

to

the

last

interface

cable

connector

(farthest

from

the

computer).

• When

using

drives

with

a

Head

Load

option,

jumper

the

drives

for

"head

load

with

motor

on"

rather

than

"head

load

with

drive

select"

jumpering.

2.2.6

SCSI/PLUS

Interface

The

SCSI/PLUS

interface

(J8)

uses

a

50-pin

male

header

connector

to

interface

with

SCSI-compatible

peripherals.

Table

2-8

shows

the

signal

names

and

numbers

for

the

SCSI/PLUS

bus

interface

connector.

Refer

to

your

disk

con-

troller

documentation,

or

the

ANSI

SCSI

(X3T9.2)

specification,

for

infor-

mation

on

the

signal

functions.

Table

2-8.

SCSI

Interface

Connector

(.18)

Signal

Function

1 -

49

(All

odd

pins)

Signal

grounds

2

-DBO

Data

Bit

0

(LSB)

4

-OBI

" " 1

6 -DB2 " " 2

8 -DB3 " " 3

10

-DB4 " " 4

12

-DB5 " " 5

14

-DB6 " " 6

16

-DB7 " " 7

(MSB)

18

-DBP

Data

Parity

20,22,24

Ground

Signal

Ground

25

---

(Not

used)

26 TERMPWR

Termination

+5

VDC

28,30

Ground

Signal

Ground

32

-ATN

Attention

34

Ground

Signal

Ground

36 -BSY

Busy

38 -ACK

Transfer

Acknowledge

40

-RST

Reset

42 -MSG

Message

44 -SEL

Select

46

-C/D

Control/Data

48

REQ

Transfer

Request

50

-I/O

Data

direction

2-7

This

interface

can

serve

a

variety

-of

purposes,

including

connection

of

hard

disk

controllers,

tape

controllers,

printer

and

communication

servers,

etc.

In

addition,

the

interface

signals

may

be

used

as

direct

input/output

lines,

allowing

the

connection

of

TTL-level

interfacing

devices

and

sensors,

etc.

The

output

signals

are

open

collector,

48mA

drivers,

and

may

be

enabled

and

disabled

under

software

control.

On-board

removable

resistor

networks

provide

bus

termination.

2.2.1

ID

Input

Port

Eight

pairs

of

jumper

pins

(J

7)

provides

an

ID

Input

Port,

which

can

be

used

by

SCSI-related

software

to

determine

the

board's

SCSI

bus

ID

for

bus

arbitra-

tion

(or

other)

purposes.

If

not

required

for

this

purpose

the

ID

Input

Port

can

be

used

as

a

general

purpose

8-bit

input

port

connector,

with

a

flat

ribbon

cable

connector

plugged

onto

J7.

Table

2-9

shows

the

signal

names

and

numbers

for

J7.

Table

2-9.

ID

Input

Port

(

...

1)

Signal

Function

1 -ID7 ID

Bit

7

(MSB)

3 -ID6 " " 6

5 -ID5 " " 5

7 -ID4 " " 4

9 -ID3 " " 3

11

";ID2

" " 2

13

-IDI

" " 1

15 -IDO " " o

(LSB)

2-16

Ground

Signal

Ground

2.3

BOARD

JUMPER

CONFIGURATIONS

Little

Board/PLUS

contains

nine

sets

of

jumpers,

which

may

be

used

to

customize

the

board's

operation.

The

jumper

sets

consist

of

either

two

or

three

pins,

with

1 a

square

pad;

each

jumper

set

is

outlined

with

white

boxes

on

the

component

side

of

the

"board.

The

options

available

through

these

jumpers

are

described

in

the

following

paragraphs.

NOTE

Do

not

solder

wires

to

the

jumper

pins,

as

this

may

void

your

board's

warranty.

Use

wire

wrap,

or

snorting

plugs

instead.

2-8

For

normal

operation,

no

jumper

setup

is

required.

All

of

the

jumper

settings

are

factory-set,

by

means

of

shorting

plugs

on

the

pins,

or

traces

on

the

bottom

side

of

the

board.

Use

of

J7

(SCSI

bus

ID)

varies,

according

to

software

requirements.

AMPRO's

standard

hard

disk

software

does

not

require

the

use

of

J7.

"IIPI

-

Clock

This

jumper,

when

shorted,

connects

the

system

16

mHz

master

clock

bus

to

the

16

mHz

hybrid

oscillator

(U2).

It

is

intended

for

test

purposes

only.

FACTORY SETTING:

shorted

"IIP2

-CTC

CLK/TRG3

This

jumper

connects

the

CTC's CLK/TRG3

input

(JMP2-2)

to

either

the

1772

FDC's

interrupt

request

output

signal

(JMP2-3)

or

to

the

CTC's

ZC/TC2

output

signal

(JMP2-1).

FACTORY SETTING:

both

options

open

JIIP3

-CTC

CLK/TRG2

This

jumper,

when

shorted,

connects

the

5380

SCSI

controller's

interrupt

request

output

signal

(JMP3-2)

to

the

CTC'S CLK/TRG2

input

(JMP3-1).

FACTORY SETTING:

open

JMP4 -

U6

Option

This

jumper

is

shorted

for

8 mHz

-only

operation

of

the

1772

FDC

device.

NOTE:

If

this

jumper

is

shorted,

the

clock

multiplexor

IC,

U6

must

not

be

present;

if

U6

is

present,

this

jumper

must

be

open.

FACTORY SETTING:

open

(U6

present)

JMP5,6

-

EPROM

Type

These

jumpers

are

used

to

program

the

board

for

various

types

of

EPROM

devices.

These

two

jumpers

are

set

as

shown

in

Table

2-10.

2-9

Table

2-10.

EPROM

Jumper

Configurations

EPROM

Type

JMP5:

1-2

JMP5:

2-3

JMP6

2732

open

short

*

2764 * *

open

27128

short

open

27256

short

open

short

Factory

setting:

open

short

open

Notes

(1)

Items

indicated

by

*

can

be

open

or

shorted;

however

do

not

short

both

JMP5

options

simultaneously.

(2) When a 2732

24-pin

EPROM

is

used,

it

must

be

plugged

into

the

lower

24

pins

of

the

28-pin

EPROM

socket,

so

that

the

2732's

1

plugs

into

3

of

the

socket.

dMP7

-

DART

RIA

This

jumper,

when

shorted,

connects

the

1772

FDC's

DRQ

output

singal

(JMP7-2)

to

the

DART's

RIA

input

(JMP7-1).

FACTORY SETTING:

open

dllP8

-

DART

DCDA

This

jumper,

when

shorted,

connects

the

5380

SCSI

controller's

DRQ

output

singal

(JMP8-1)

to

the

DART's

RIA

input

(JMP8-2).

FACTORY SETTING:

open

dllP9

-

SCSI

Termination

Power

This

jumper,

when

shorted,

connects

the

board's

+5V

DC

power

to

the

SCSI

bus

signal

line

provided

for

optional

external

termination.

FACTORY SETTING:

open

2-10

Ampro Little Board/PLUS User manual

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