Commodore: A4091
DKB: 4091
Connection: Zorro III

Commodore A4091
Commodore A4091

Front of 4091
Front of 4091

Back of 4091
Back of 4091

DKB 4091 with items
DKB 4091 with items

Hi Res Version, Commodore A4091 - 60K
Hi Res Version, Front of 4091 - 583K
Hi Res Version, Back of 4091 - 577K
Hi Res Version, DKB 4091 with items - 764K
Image of DKB 4091 Box, Front - 145K
Image of DKB 4091 Box, Back - 160K
Image of 4091 backplate - 75K

This card was originally designed and sold by Commodore, but was later manufactured and sold under license by DKB. The A4091 is a full-length Zorro-III DMA Fast SCSI-II hard drive controller designed for the A4000. It is based on the NCR 53C710 chip. Unlike some similar products, it is only a Fast SCSI-2 controller; it has no sockets for additional RAM. The A4091 package includes an active terminator and a custom ribbon cable, which is nicely folded to accommodate up to five internal drives, one on-board and a pair in each of the front and rear bays. The A4091 requires a revision 11 Buster, which Commodore supplied loose with the card. It works with A3640 3.1 and 3.2 revisions, but not 3.0. The board is theoretically capable of 10 megabytes per second transfer rates.

Board Layout

  _________________________________________________________________
 | ... ... LED      :::::::::::::::                                |___
 |                    50-Pin SCSI                                  |
 | ||| ||| |||         Connector                                   |
 | ||| ||| ||| |||                                                 |#
 |             |||      ||||||                                     |# External
 | ||| ||| ||| |||      ||||||                                     |# HiDensity
 | ||| ||| ||| |||      ||||||                                     |# SCSI-2
 |                      ||||||                                     |# Connector
 | |||     |||                                                     |#
 | ||| ||| |||                                                     |=sw 8
 |     |||                      . Power                            |=   :
 |                              : Connector                        |=   :
 |_________________________________________________________________|=sw 1
     ||||||||||||||||||||||||||||||                                |
LED Connectors

To DSPLY To MB

CN351 CN308
-------------------------
| o o o o o o
|
| N R B B R N
| C e l l e C
| d a a d
| c c
| k k
|

Unplug the Front Panel LED cable from the connector on the motherboard and plug it into the CN351. To make the LED operate for IDE drives as well, use the extra cable supplied with the A4091 to connect CN308 to the motherboard.

Rear Connector View

---------------------------------------------------------------
| |
| DIP Switch External SCSI-2 Connector |
| _________________ |
| ON | | 1 25 |
| | 1 2 3 4 5 6 7 8 | {}:::::::::::::::::::::::::{} |
| OFF |_________________| 26 50 |
| |
---------------------------------------------------------------

DIP Switch Settings, defaults are all OFF

SCSI Address of Card

0 1 2 3 4 5 6 7

SW1 ON OFF ON OFF ON OFF ON OFF
SW2 ON ON OFF OFF ON ON OFF OFF
SW3 ON ON ON ON OFF OFF OFF OFF

SCSI Fast Bus

SW4 OFF indicates that the SCSI Fast Bus feature is enabled.
Set this switch to ON if none of your SCSI devices
support SCSI Fast Bus.

Short/Long Spinup

SW5 OFF indicates that your system uses the standard spinup
(booting) time. Set this switch to ON to request a longer
booting period. If one of your SCSI devices has a long
power-on cycle, the Amiga may not recognise it during the
standard booting period.

Synchronous Mode

SW6 OFF indicates that the synchronous mode feature is enabled.
Set this switch to ON to disable synchronous mode. Synchronous
mode does not require acknowledgement for every byte transmitted,
which can mean improved response time with most SCSI devices.

External SCSI Termination

SW7 OFF indicates that you do not have any external devices.
This activates the terminator on the board since this is
one end of the SCSI bus. Set this switch to ON when you
install an external device. This disables the termination
on the board since it is now in the middle of the SCSI bus
(not at the end).

Logical Unit (LUN) Enable

SW8 OFF indicates that unit 0 is the only unit recognized. Set
this switch to on to enable the system to recognize 1-6 as
LUNs.

Contributions to this page by:
Bob Emery, Francisco Rabay Jr, Iggy Drougge, Warren Block


Einem link gefolgt? Hier gehts zur Hauptseite

Followed a link? Please go to the Main Site