Sony CDU-541 - Page 25

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CDU-541 CD-ROM DRIVE SCSI INTERFACE MANUAL
The Sub-channel Q data contains the following:
4
bits
Reserved
4
bits
Control Field
8 bits
Track Number Field in
bcd format
8
bits
Index Number Field in
bcd format
8
bits
Relative Minute Field
in bcd format
8
bits
Relative Second Field
in bcd format
8
bits
Relative Frame Field in bcd format
8
bits
Absolute
Minute Field in bcd format
8
bits Absolute Second Field in bcd format
8
bits
Absolute Frame Field in bcd format
72 bits total sub-channel Q data
The data symbols make up the block of data that is returned to the user
during a read operation. A block of data is made up of 98 frames, so there
are (98 x 24) 2352 bytes of data in a block. A block of data contains the
following if the CD-ROM Mode field has a value of one:
12
bytes
Synchronization
4 bytes
CD-ROM data header
Absolute Minute Field in
bcd format
Absolute Second Field in
bcd format
Absolute Frame Field
in bcd format
CD-ROM Mode Field
2048 bytes
user defined data
-
4 bytes Error Detection Code
8 bytes zero
276
bytes Layered Error
Correction
Code
A block of data contains the following if the CD-ROM Mode field has a value
of two:
12
bytes Synchronization
4 bytes CD-ROM data header
Absolute Minute Field in bcd format
Absolute Second Field in bcd format
Absolute Frame Field in bcd format
CD-ROM Mode Field
2336 bytes user defined data
NOTE: Many drives are capable of returning CD-ROM Mode one data in a 00-
ROM Mode two format. This allows the user to investigate the error
detection and error correction codes. However if the data is encoded as
CD-ROM Mode two it cannot be read as CD-ROM mode one data.
The address in the CD-ROM Header field is usually the same as the address in
the sub-channel Q data for a particular sector. However a tolerance of + one
second is allowed.
The address in the TOC for the start of user data in track has a tolerance
of + 0 second.
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