42 Barracuda 18XL Product Manual, Rev. A
8.1.1 Function description
J2
jumper
installation Jumper function description
TE
(Applies only to “N” and “W” models)
On
With the jumper installed, the onboard (non-removable) terminator circuits are enabled (con-
nected to the I/O lines).
Default
is jumper installed.
Off Terminator circuits not enabled (not connected to I/O lines).
SE
On Forces drive to use single-ended I/O drivers/receivers only.
Off Drive can operate on the interface in low voltage differential mode or single-ended,
depending on the voltage state of the I/O “DIFFSNS” line.
Default
is no jumper on.
DS ME
Off
Off Spindle starts immediately after power up—
Default
setting.
Off On Drive spindle does not start until Start Unit command received from host.
On Off Spindle Startup is delayed by SCSI ID times 12 seconds after power is applied, i.e., drive 0
spindle starts immediately when DC power connected, drive 1 starts after 12 second delay,
drive 2 starts after 24 second delay, etc.
On On Drive spindle starts when Start Unit command received from host. Delayed start feature is
overridden and does not apply when
ME
jumper is installed.
WP
On Entire drive is write protected.
Off
Drive is not write protected.
Default
is no
WP
jumper installed.
PD
On Parity checking and parity error reporting by the drive is disabled.
Off
Drive checks for parity and reports result of parity checking to host.
Default
is
PD
jumper not installed.
RES (2)
Off
Reserved jumper position. Default is no jumper installed.
TP
(Not for “LC” model)
Off No terminator power is connected to drive terminators or SCSI bus I/O cable.
1
No jumpers
on is factory
default.
1. See Figure 7d and 7e for pins used for Termpower.
On Drive supplies power to SCSI bus I/O cable.
1
A jumper on the
TP
position may be needed to
power external terminators (see Section 9.8 and Figure 10a).
TP1 and TP2
(Applies only to “N” and “W” models)
On This horizontally-positioned jumper across the two
TP
positions furthest from the PCB edge,
connects terminator power from SCSI bus I/O Termpower cable
2
to the drive’s internal termi-
nators (for single-ended I/O only).
2. See Figure 7d for pins used for Termpower.
Off See above explanations for
TP
jumpers.
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