Industrial Micro Systems 464 - Configuring the 464 Board; Phantom Line (JACK JD) Configuration; Enable I;O (JACK JB) Setting; I;O Address Selection (JACK JC)

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The

464

board

features

a

parity

circuit

to

provide

increased

data

security.

A

parity

bit

is

written

during

every memory

write

such

that

the

total

number

of

"1"

bits

written

are

odd.

During

memory

reads

the

total

number

of

"1"

bits

are checked.

The

parity

error

is

set

if

the

number

of

"1"

bits

checked

are

even,

Parity

errors

during

memory reads

can

interrupt

or

stop

the

CPU. A LED

r-

indicator

on

the

board

is

lighted

to

indicate

the

error,

The

status

of

the

parity

circuit

may

be

read

J

from

the

memory

board's

I/O

Port.

CONFIGURING

THE

464

BOARD

PHANTOM LINE OACK JO)

The

phantom

signal

(pin

67)

shunt

is

etched

so

that

the

board

will

be

disabled

by

an

activated

Phantom

Line.

1£

this

is

not

desirable,

then

the

etch

connecting

the

two

pads

of

JD (PH) may

be

cut

on

the

rear

of

the

board.

aD

must

be

connected

when

using

the

464

board

with

Industrial

Micro

System

CPU

boards,)

Note:

The

Phantom

Line

affects

memory

read

operations

only.

Memory

write

operations

are

not

affected

by

the

Phantom

Line. . ,

EN

I/O

OACK JB)

-...J

THE

"EN

I/O"

(Enable I/O)

shunt

JB

must

be

installed

for

the

board

to

respond

to

I/O

commands.

This

will

be necessary

for

bank

mode

or

parity

operations.

I/O

SELECTION

OACK

JC)

The

selection

of

the

boards

I/O

address

is

done

on

jack

JC.

The

jack

is

labeled

0-7

(top

to

bottom)

for

the

respective

address

bits

(AO-A7)

of

the

I/O

address.

A

"1"

is

programmed

by remoyin¥ a

shunt.

Thus,

to

program

I/O

address

OFH

the

top

four

shunts

(0-3)

would

be

removed

("l's")

and

.J

the

bottom

four

shunts

(4-7)

would

be

installed

("O's"),

(Note

that

the

liEN

1/0"

shunt

must

be

on

for

the

board

to

respond

to

the

I/O

command.)

CPU

SELECTION

OACK

JF)

, i

The

8080

shunt

(JF)

should

be

installed

for

systems

using

8080

CPU's.

For

2-80

systems

this

shunt

should

be

removed.

FRONT

PANEL OACK JH)

If

the

464

board

is

to

be

used

with

an

"IMSAI"

front

panel,

the

shunt

JH

must

be

in

the

right-most

(FP)

position.

MEMORY

SPEED

OACK JA)

The

JA

shunt

controls

the

timing

of

the

memory

board.

The

H

position

is

for

200NS

RAMS

and

the

L

position

is

for

250NS

RAMS.

This

shunt

is

factory

installed

on

the

H

position

and normally

should

not

be

changed.

High

speed

operation

is

required

for

the

2-80

processor.

INDUSTRIAL

MICRO

SYSTEMS.

INC.

000464

REV A

8/12/80

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