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CDU-541 CD-ROM DRIVE SCSI INTERFACE MANUAL
5.2.33.
START/STOP UNIT Command
==============================================================================
Bit:
7
6
5
4
3
2
1
o
Byte :
==============================================================================
o
:
Operation Code (lBh)
1
-----1-----------------------------------------------------------------------1
1
: Logical Uni t Number:
R e s e r v e d : Immed
-----i-----------------------------------------------------------------------
2
i
Reserved
-----I----------------------------------------------~------------------------
3
1
Reserved
-----1-----------------------------------------------------------------------
4
I
Reserved
I
LoEj
I
Start
f
-----1-----------------------------------------------------------------------1
5
I
Control Byte
I
==============================================================================
The START/STOP UNIT command requests that the controller enable or disable
the logical unit for further operations.
An
immediate (Immed) bit of one indicates that status will be returned as
soon as the operation is initiated.
An
Immed bit of zero indicates that
status will be returned after the operation is completed.
A load/eject (LoEj) bit of zero indicates that no action is to be taken
regarding loading or ejecting the disc.
A LoEj bit of one indicates that the
disc is to be unloaded if the start bit is zero.
A start bit of one requests the logical unit be made ready for use.
A start
bit of zero requests that the logical unit be stopped.
LoEj
Start
Description
o
o
1
1
o
1
o
1
spin down the disc, optical pick-up is not moved
spin up the disc. seek to last address requested
spin down the disc. eject the caddy
not supported
If a PREVENT MEDIUM REMOVAL command has been issued.
a request to eject the
disc will be terminated with a CHECK CONDITION status.
The sense key will be
set to ILLEGAL REQUEST, and the additional sense code set to PREVENT BIT SET.
5-60
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