Chapter 4 SCSI Commands
MODE SENSE (6) / (10) Command (1Ah / 5Ah)
DLT-S4 Interface Reference Guide
193
Table 109
Parallel SCSI
—
SPI Negotiated Settings Mode
Subpage — Field Descriptions
Field
Description
PS
Parameters Savable. Always set to 0.
SPF
SubPage Format. Always set to 1. Indicates that this page uses the
sub_page mode format.
Page Code
Identifies the type of
MODE SENSE
page being transferred. A value of 19h
identifies this as the Port Control Page.
Subpage Code
Identifies the type of
MODE SENSE
subpage being transferred. A value of
03h identifies this as the SPI Negotiated Settings Mode Subpage.
Page Length
Indicates the number of bytes in the page, excluding the 4 bytes that make
up the header.
Protocol Identifier
A value of 1h indicates that this mode page applies to an SPI-5 compliant
port (see the
SCSI Parallel Interface – 5
(SPI–5) standard.
Transfer Period Factor
Indicates the negotiated Transfer Period Factor for the current I_T nexus
(see the
SCSI Parallel Interface – 5
(SPI–5) standard.
REQ/ACK Offset
Indicates the negotiated REQ /ACK Offset for the current I_T nexus (see
the
SCSI Parallel Interface – 5
(SPI–5) standard).
Transfer Width Exponent
Indicates the negotiated REQ /ACK
Offset for the current I_T nexus.
Value
Description
00h
Specifies 8 bit data bus (i.e.
narrow transfer agreement).
01h
Specifies 16 bit data bus (i.e. wide transfer agreement)
Protocol Options Bits
Indicates the negotiated Protocol Options for the current I_T nexus (see
the
SCSI Parallel Interface – 5
(SPI–5) standard).
Transceiver Mode
Indicates the current Transceiver Mode, as defined below:
Code
Bus Mode
00b
Unknown
01b
Single ended
10b
Low Voltage Differential
11b
High Voltage Differential (not supported)
Sent PCOMP_EN
Indicates the PCOMP_EN bit sent for the current I_T nexus.
Received PCOMP_EN
Indicates the PCOMP_EN bit received for the current I_T nexus.