Chapter 4 SCSI Commands
MODE SELECT (6) / (10) Command (15h / 55h)
DLT-S4 Interface Reference Guide
136
Table 82
Parallel SCSI
— SPI
Negotiated Settings Mode
Subpage — Field Descriptions
Field
Description
PS
Parameters Savable. For
MODE SELECT
, must be set to 0.
SPF
SubPage Format. Always set to 1. Indicates that this page uses the page_1 page
format.
Page Code
Identifies the type of
MODE SELECT
page being transferred. A value of 19h identifies
this as the Port Control Page.
Subpage Code
The
SUBPAGE CODE
field indicates which mode subpage is being accessed. Mode
subpage code values are listed in SPI-5. If the parameter data of a
MODE SELECT
command contains a mode subpage formatted mode page with the
SUBPAGE CODE
field is set to zero, the SCSI target device returns a
CHECK CONDITION
status. The
sense key sets to
ILLEGAL REQUEST
and the additional sense code set to
ILLEGAL
FIELD IN PARAMETER LIST
.
Page Length
Indicates the number of bytes in the page, excluding the 4 bytes that make up the
header. The length is returned in
MODE SENSE
commands and must subsequently be
set to the same value when performing
MODE SELECT
.
Protocol
Identifier
A value of 1h indicates that this mode page applies to a SPI-5 compliant port (see the
SCSI Parallel Interface - 5
(SPI-5) standard).
Transfer Period
Factor
The
TRANSFER PERIOD FACTOR field
indicates the negotiated transfer period factor
for the current I_T nexus.
REQ/ACK
Offset
The
REQ/ACK Offset
field indicates the negotiated
REQ/ACK
offset for the current I_T
nexus.
Transfer Width
Exponent
The
TRANSFER WIDTH EXPONENT
field indicates the negotiated transfer exponent for
the current I_T nexus.
Protocol
Options Bits
The
PROTOCOL OPTIONS BITS
field indicates the negotiated protocol options for the
current I_T nexus.
Transceiver
Mode
The
TRANSCEIVER MODE
field specifies the current bus mode of the SCSI target port
as defined below:
Code
Bus Mode
00b
Unknown
01b
Single ended
10b
Low Voltage Differential
11b
High Voltage Differential (not supported)
