Pioneer SCSI-2 - Manual (Page 80)

Play Audio(10)
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2.11 Play Audio(10) (45h)
Operation Code is (45h).
Logical Block Address
The logical block address field specifies the logical block at which the audio play back
operation will begin. If all bytes in the logical block address field are set to FFh, it means
to start at the current optical head location. This feature allows the host to modify the audio
ending address without interrupting the current audio playback operation.
Transfer Length
Specifies the number of contiguous logical blocks that will be played. A transfer length
field of zero indicates that no audio operation will occur. This condition will not be
considered an error. Any other value indicates the number of logical blocks that will be
played.
The PLAY AUDIO(10) command requests that the target play audio starting at the specified
logical block address for the specified transfer length. The command function (Immed bit) and
the output of audio signals will be as specified by the settings of the audio control parameters in
the MODE SELECT PAGE CODE E.
The status returning condition depends on the Immed bit of MODE SELECT page code E. The
Immed bit in MODE SELECT page code E of one requests that this command return the status
byte as soon as the audio playback operation has been started. The Immed bit in MODE
SELECT page code E of zero requests that this command return the status byte when audio
playback operation is completed, or an error occurs.
If any commands related to audio operations are implemented then the PLAY AUDIO command
will be implemented to allow a method for the initiator to determine if audio operations are
supported. A target responding to a PLAY AUDIO command which has transfer length of zero
with Check Condition status and setting the sense key to ILLEGAL REQUEST does not support
audio play operations.