Adaptec 1542B User Manual - Page 6

Section

Two

Preparation

and

Configuration

2.3.1.5

DMA

Channel

There

are

two

jumper

blocks

involved

in

selecting

the

DMA

channel.

These

are

J5

and

J9.

The

DMA

channel

selection

jumpers

consist

of

pin

pairs

7

and

8

located

in

the

large

block

of

jumper

pins

J5.

The

DMA

channel

reported

to

the

AT

during

the

Return

Configuration

command

is

set

by

these

jumpers

according

to

the

following

table.

Default

is

DMA

channel

5.

Jumper

set

J9,

pairs

1

through

4,

selects

the

DMA

REQ

signal

to

be

used

by

the

AHA-1540B/1542B.

This

jumper

set

is

located

near

the

bottom

center

of

the

host

adapter.

Pin

pair

1

is

the

leftmost

pair

of

pins.

Default

is

DMA

Request

5.

Jumper

set

J9,

pairs

5

through

8,

selects

the

DMA

ACK

signal

to

be

used

by

the

AHA-1540B/1542B

according

to

the

following

table.

This

jumper

set

is

located

near

the

bottom

center

of

the

host

adapter.

Pin

pair

1

is

the

leftmost

pair

of

pins.

Default

is

DMA

Acknowledge

5.

There

are

four

DMA

channels

that

may

be

chosen

for

use

by

the

AHA-1540B/AHA-1542B,

channels

0,

5,

6,

and

7.

The

DMA

channel

is

set

up

by

using

the

jumper

blocks

and

pin

-pairs

as

previ-

ously

described.

The

jumper

settings

for

each

channel

are

shown

in

the

following

diagrams:

AHA-1540B/1542B

2-5

adaptec

Adaptec 1542B User Manual - Page 6

AHA-1540B/AHA-1542B

Page 6 highlights