Adaptec AHA-1540b/1542b SCSI Host Adapter
Default settings are in Bold or are selected by a 
.
J5: GENERAL CONTROL
| SCSI Address |
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 |
|---|
| J5(4) | X | -- | X | -- | X | -- | X | -- |
|---|
| J5(5) | X | X | -- | -- | X | X | -- | -- |
|---|
| J5(6) | X | X | X | X | -- | -- | -- | -- |
|---|
7 is the Default setting.
| DMA Channel |
| 0 | 5 | 6 | 7 |
|---|
| J5(7) | X | -- | X | -- |
|---|
| J5(8) | X | X | -- | -- |
|---|
5 is the Default setting.
| Interrupt Channel |
| 9 | 10 | 11 | 12 | 14 | 15 |
|---|
| J5(9) | -- | X | -- | X | -- | X |
|---|
| J5(10) | -- | -- | X | X | -- | -- |
|---|
| J5(11) | -- | -- | -- | -- | X | X |
|---|
11 is the Default setting.
| DMA Transfer Speed |
| 5.0 | 5.7 | 6.7 | 8.0 |
|---|
| J5(12) | -- | X | -- | X |
|---|
| J5(13) | -- | -- | X | X |
|---|
5.7 is the Default setting.
J6: BIOS/AUTO SENSE CONTROL
J7: ADDRESS SELECTION
| I/O Port Address |
| 334 | 330 | 230 | 134 | 130 |
|---|
| J7(2) | -- | X | -- | X | --
|
|---|
| J7(3) | -- | -- | X | X | --
|
|---|
| J7(4) | -- | -- | -- | X | X
|
|---|
330 is the Default setting.
| BIOS Wait State (ns) |
| -0- | 100 | 200 | 300 |
|---|
| J7(5) | -- | X | -- | X
|
|---|
| J7(6) | -- | -- | X | X
|
|---|
0 Wait States is the Default setting.
| BIOS Address |
| DC00 | CC00 | D800 | C800 |
|---|
| J7(7) | -- | X | -- | X
|
|---|
| J7(8) | -- | -- | X | X
|
|---|
DC00 is the Default setting.
J8: FLOPPY DISK SELECTION (AHA-1542B Only)
J9: HOST ADAPTER DMA/IRQ SELECTION
This Host Adapter may also be ordered with a SCSI-2 External Connector, as part
number 1540b100, or 1540b100.
Starting with their v3.20 BIOS & uCODE, Adaptec added support for drives over
1 Gigabyte in size. The new code utilizes a previously reserved pin - J6(2) - for
enabling this support. This will not affect drives of less than 1GB that are attached.
Also added was support for peripherals which have longer start-up times, notably, some
IBM drives (The 0661 Lightning Series comes to mind.)
[ F1 ]: Fuse, 1.5 Amp, 125 Volt
[ =5= ]: Termination Resistor, 220/330 Ohm
| 1540b | 1542b |
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