CDU-541
CD-ROM
DRIVE
SCSI
INTERFACE
MANUAL
5
.2.
3 .
MODE
SENSE
CollUlland
==============================================================================
Bit
I
Byte
:
7
6
5
4
3
2
1 o
=============================================================================-
o i
Operation
Code (lAh)
-----i-----------------------------------------------------------------------
1 :
Logical
Unit
Number
i
Reserved
-----1-----------------------------------------------------------------------
2 i
PC
i
Page
Code
-----i-----------------------------------------------------------------------
3 :
Reserved
I
-----1-----------------------------------------------------------------------i
4 1
Allocation
Length
1
-----1-----------------------------------------------------------------------\
5 1
Control
Byte
:
==============================================================================
The
MODE
SENSE
command
provides
a means
for
a
controller
to
report
parameters
to
the
initiator.
It
is
a complementary
command
to
the
MODE
SELECT
command.
The
page
control
(PC)
field
defines
the
type
of
parameter
values
to
be
returned
as
shown below.
Table
5-5:
Page
Control
Bit
Definition
======================================
DB(7)
DB(6)
Type
of
Parameter
Values
------------------------
0 0
Current
Values
0
1
Changeable
Values
1
0
Default
Values
1 1
Default
Values
======================================
5.2.3.1.
Current
Values
A
PC
field
value
of
Oh
requests
the
controller
return
the
current
values
for
the
page
code
specified.
The
current
values
returned
are
either
the
parameters
set
in
the
last
successful
MODE
SELECT
command
or
the
default
values
if
a
MODE
SELECT
command
has
not
been
executed.
5.2.3.2.
Changeable
Values
A
PC
field
value
of
lh
requests
the
controller
return
the
changeable
values
for
the
page
code
specified.
The
page
requested
will
be
returned
with
the
bits
that
are
allowed
to
be
changed
set
to
one.
Parameters
that
are
not
changeable
will
be
set
to
zero.
If
any
part
of
a
field
is
changeable
all
bits
in
that
field
are
set
to
one.
The
page
descriptor
as
defined
in
this
document
will
always
be
returned
even
if
none
of
parameters
are
changeable
within
the
page.
5-11
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