SC2500 User Guide Ver 2.1
May 6, 2003
Page 23 of 26
6.2 Default Jumper Configuration
Definition
State
Switches
a.
SCSI ID
Device 0
ID0 – OFF
Switch pos. 1 OFF
ID1 - OFF
Switch pos. 2 OFF
ID2 - OFF
Switch pos. 3 OFF
b.
Termination
Disabled
Switch pos. 4 OFF
c.
Term Power
Cable
Switch pos. 5 OFF
d.
Writes
Enabled
Switch pos. 6 OFF
e.
SCSI ID Source
Connector
Switch pos. 8 ON
6.3 SCSI ID Selection
6.3.1 The SC2500 can use any of the 8 SCSI IDs available on the SCSI bus,
although the highest priority device, SCSI ID 7, is usually reserved for the
initiator. Switch selection for each SCSI ID is shown below. To use the main
interface connector for ID setting, the jumper SW1-8 must be on. To use the
switch block, SW1-8 must be off.
ID2 or SW2 ID1 or SW2 ID0 or SW1
SCSI ID SELECTED
ON
ON
ON
SCSI ID 7
ON
ON
OFF
SCSI ID 6
ON
OFF
ON
SCSI ID 5
ON
OFF
OFF
SCSI ID 4
OFF
ON
ON
SCSI ID 3
OFF
ON
OFF
SCSI ID 2
OFF
OFF
ON
SCSI ID 1
OFF
OFF
OFF
SCSI ID 0
6.4 Write Protection
The WP switch of jumper is used to write protect the SC2500. When the
host processor sends a write command, the condition of this switch is
checked. If switch SW1-6 is on, writes are disabled, and an error message
will be returned to the SCSI controller. Moving the switch to the off position
will enable writes on the board, allowing full read/write access to the
memory array.
6.5 Termination
Memtech’s SC2500 employs active termination on the SCSI drive.
Termination is normally disabled on the drive. To enable termination, move
SW1-4 to the ON position. To supply power to the Termination Power line
on the SCSI cable, move SW1-5 to the ON position. Power is sourced to
the SCSI cable through a Schottky diode. Normally, power is supplied to
the drive from the cable and the host adapter.
