Intel
®
Carrier Grade Server TIGPT1U TPS
Midplane Board
Revision 1.0
55
7.3.4.1
LVD SCSI Connectors
The low voltage differential (LVD) connector carries signals between the midplane SCSI bus
and internal SCSI drives through the SCSI SCA connectors. The LVD SCSI bus’s signals are
driven by either the baseboard SCSI controller, the LVD/SE Transceiver, or the internal SCSI
drives. Table 7-1 provides a description of each signal on the SCSI connectors.
Table 7-1. LVD SCSI Bus Signals – J2L1, J4A1, J8A1
Signal
Type
Driver
Name and Description
DB_[15..0][P, N]
I/O
LVD/
SCSI Data Bus.
These pins, with the DBP[1/0][P/N] pins
form the bi-directional SCSI data bus.
DB_P0[P, N]
DB_P1[P, N]
I/O LVD/
SCSI Data Parity.
These pins support parity on the SCSI
bus. DBP0[P/N] supports parity for data [7..0]
DBP1[P/N] supports parity for data [15..8]
DIFFSENSE I
Analog
Differential Sense.
This pin monitors the DIFFSENSE
signal from the terminator. The voltage level determines
the operating mode of the target devices on the SCSI bus.
If the voltage on the DIFFSENSE signal is from –0.35 V to
+0.5 V the mode will be SE. If it is from +0.7 V to 1.9 V the
mode will be LVD.
ATN_[P, N]
I/O
LVD/
SCSI Bus Attention.
These pins are asserted by a SCSI
device in initiator mode to alert the target that the initiator
has a message to transfer.
BSY_[P, N]
I/O
LVD
SCSI Bus Busy.
In SE mode, these pins are bi-directional
and are asserted to gain use of the SCSI bus and to
indicate that that SCSI bus is in use.
ACK_[P, N]
I/O
LVD
SCSI Bus Acknowledge.
These pins are asserted by a
SCSI device in initiator mode to acknowledge the target’s
request for a data transfer.
RST_[P, N]
I/O
LVD
SCSI Bus Reset.
In SE mode, these pins are bi-directional
and are asserted when all the SCSI devices attached to the
SCSI bus need to be reset.
MSG_[P, N]
I/O
LVD
SCSI Bus Message Phase.
These pins are asserted by a
SCSI device in target mode to indicate the Message In or
Message Out phase.
SEL_[P, N]
I/O
LVD
SCSI Bus Select.
In SE mode, these pins are bi-
directional and are asserted by the controller when
attempting to select or reselect a SCSI device.
CD_[P, N]
I/O
LVD
SCSI Bus Control/Data Phase.
These pins are asserted
or de-asserted by a SCSI device in target mode to indicate
that control or data information is being transferred over the
SCSI bus
REQ_[P, N]
I/O
LVD
SCSI Bus Request.
These pins are asserted by a SCSI
device in target mode to indicate that the target is
requesting a data transfer over the SCSI bus.
IO_[P, N]
I/O
LVD
SCSI Bus I/O Phase.
These pins are asserted by a SCSI
device in target mode to indicate the direction of data
movement on the SCSI bus between the target and the
initiator.
SCSI_ID O
GND/OPEN
SCSI ID.
Sets internal SCSI ID depending on slot. Drive 0
has SCSI address 0. Drive 1 has SCSI address 1.
MATED [1,2]
I/O
TTL
SCSI MATED.
Pins are used to determine if SCSI is
present and has proper contact. See T10/1302D Annex C
for additional information.
