Adaptec AHA-1540A/1542A SCSI Host Adapter
J2: Internal SCSI Drive Connector
J3: External SCSI Drive Connector
J4: Floppy Drive Connector
J5: Hard Drive LED Connector
Default settings are in Bold or are selected by a 
J1(1): Synchronous Negotiation
Open: Target initiates negotiation.
Jumpered: Host Initiates negotiation.
J1(2): Diagnostics Jumper
Open: Normal Operation.
Jumpered: Host runs continuous diagnostics.
J1(3): SCSI Parity
Open: Parity checking enabled.
Jumpered: Parity checking disabled.
| J1(4,5,6): SCSI ID |
| J1(4) |
J1(5) |
J1(6) |
SCSI ID |
| - |
- |
- |
#7 |
| X |
- |
- |
#6 |
| - |
X |
- |
#5 |
| X |
X |
- |
#4 |
| - |
- |
X |
#3 |
| X |
- |
X |
#2 |
| - |
X |
X |
#1 |
| X |
X |
X |
#0 |
(Default is #7)
| J1(7,8): DMA Channel |
| J1(7) |
J1(8) |
DMA# |
| - |
- |
7 |
| X |
- |
6 |
| - |
X |
5 |
| X |
X |
0 |
|
| J14: DMA REQ Channel |
| (1) |
(2) |
(3) |
(4) |
Chan# |
| X |
- |
- |
- |
#0 |
| - |
X |
- |
- |
#5 |
| - |
- |
X |
- |
#6 |
| - |
- |
- |
X |
#7 |
|
| J15: DMA ACK Channel |
| (1) |
(2) |
(3) |
(4) |
Chan# |
| X |
- |
- |
- |
#0 |
| - |
X |
- |
- |
#5 |
| - |
- |
X |
- |
#6 |
| - |
- |
- |
X |
#7 |
|
(Default DMA Channel is #5. J1(7,8), J14, & J15 should all be set to the
same value.)
| J1(9,10,11): Interrupt |
| (9) |
(10) |
(11) |
Channel |
| - |
- |
- |
#9 |
| X |
- |
- |
#10 |
| - |
X |
- |
#11 |
| X |
X |
- |
#12 |
| - |
- |
X |
#14 |
| X |
- |
X |
#15 |
|
| J16(1-6): Interrupt |
| (1) |
(2) |
(3) |
(4) |
(5) |
(6) |
IRQ |
| X |
- |
- |
- |
- |
- |
#9 |
| - |
X |
- |
- |
- |
- |
#10 |
| - |
- |
X |
- |
- |
- |
#11 |
| - |
- |
- |
X |
- |
- |
#12 |
| - |
- |
- |
- |
X |
- |
#14 |
| - |
- |
- |
- |
- |
X |
#15 |
|
| J1(12,13): DMA Speed |
| (12) |
(13) |
Speed |
| - |
- |
5.0 |
| X |
- |
5.7 |
| - |
X |
6.7 |
| X |
X |
8.0 |
 |
J7(1-4): Wait States
(1): Disable Wait States
(2): 100 Nanoseconds
(3): 200 Nanoseconds
(4): 300 Nanoseconds |
 |
| J6: AT Port Address |
| (1)A2 |
(2)A8 |
(3)A9 |
Address |
| - |
- |
- |
334h |
| X |
- |
- |
330h |
| - |
X |
- |
234h |
| X |
X |
- |
230h |
| - |
- |
X |
134h |
| X |
- |
X |
130h |
(Default Address is 330h.)
|
 |
| J10: BIOS Addr. |
| (1) |
(2) |
Address |
| - |
- |
DC000 |
| X |
- |
CC000 |
| - |
X |
DD800 |
| X |
X |
C8000 |
(Default is DC000.)
|
 |
(1) Reserved: Open
(2) Reserved: Open
(3) Reserved: Open
(4) Auto Sense
Open: Enable
Automatic Sense Request.
Jumpered:
Disable Automatic Sense Request.
|
J12: Floppy Drive Address
Open: 3F0-3F7.
Jumpered: 370-377.
 |
J17: Floppy Drive Interrupt
(1/2): IRQ#6.
(2/3): (Unknown IRQ#).
|
 |
J18: Floppy Drive DMA REQ Channel
(1/2): DMA #2.
(2/3): DMA #3.
|
 |
J19: Floppy Drive DMA ACK Channel
(1/2): DMA #2.
(2/3): DMA #3.
(Note: J18 & J19 should be set to the same channel.)
|
LA Enable Jumper (AHA-W1542A Only)
Note: This jumper exists only on the early production units. These are easily
identified by a label on the board that has a model number of AHA-W1542A.
Standard production AHA-1540A and AHA-1542A boards do not have this jumper.
When J8 is installed, address drivers LA17 - LA19 are enabled. When not
installed these address lines are not driven. Some computers, especially 80386
based machines, short address lines LA17 and SA17, LA18 and SA18, and LA19 and
SA19 together. If your computer system shorts these lines then remove jumper
J8. Default is jumper installed.
CAUTION: Incorrect installation of this jumper may not result in immediate
system problems. If it is necessary to change the state of this jumper after
the system has been configured, the SCSI hard disk must also be re-formatted.
Contact the computer system manufacturer if there is any doubt on how the
system implements these address lines.
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