Method and apparatus for automatic sector format identification in an optical storage device

An apparatus for determining a sector format of an optical disc from a digital information stream, wherein the digital information stream includes a subcode portion and a data portion, comprising:

• a clock for generating a timing signal relative to incoming bits of the digital information stream;
• a serial-to-parallel converter for processing incoming bits of the digital information stream according to the clock;
• a first register for storing the subcode portion;
• a first counter for identifying within the stored subcode portion a periodic channel;
• sector type identification logic for decoding the periodic channel to determine whether the channel indicates a particular sector type;
• and
• a first signal for identifying the particular sector type indicated by the periodic channel.

A method for identifying a sector format in a sector of an optical disc, wherein information in the sector includes a data portion and a subcode portion, comprising the steps of:

• (a) polling a data type indicator bit from a subcode portion of a sector of an optical disc;
• (b) returning a first signal in response to the data type indicator bit, wherein the first signal is representative of the data type of the sector of the optical disc;
• (c) extracting mode indicator bits from a data portion of the sector wherein the first signal is representative of a CD-ROM type sector;
• (d) returning a second signal in response to the mode indicator bits, wherein the second signal is representative of the mode of the sector of the optical disc;
• (e) extracting a fist set of subheader bytes and a second set of subheader bytes when the second signal is representative of a Mode-2 CD-ROM sector;
• (f) comparing the first set of subheader bytes with the second set of subheader bytes;
• (g) polling a form indicator bit in the first set of subheader bytes when the first set of subheader bytes is equivalent to the second set of subheader bytes;
• and
• (h) returning a third signal in response to the form indicator bit, wherein the third signal is representative of the form of the sector of the optical disc.

An apparatus for determining a sector format of an optical disc from a digital information stream, wherein the digital information stream includes a subcode portion and a data portion, comprising:

• a clock for generating a timing signal relative to incoming bits of the digital information stream:
• a serial-to-parallel converter for processing incoming bits of the digital information stream according to the clock;
• a first register for storing the subcode portion;
• a first counter for identifying within the stored subcode portion a periodic channel;
• sector type identification logic for decoding the periodic channel to determine whether the channel indicates a particular sector type;
• a first signal for identifying the particular sector type indicated by the periodic channel;
• a second register for storing the data portion;
• a second counter for identifying a header;
• sector mode identification logic for decoding the header to determine whether the header indicates a particular sector mode;
• and
• a second signal for identifying the particular sector mode indicated by the header.

A method for adjusting a size of a data field in buffer memory based upon a data type of a section of an optical disc, comprising:

• (a) polling a data type indicator bit from a subcode portion of a sector of an optical disc;
• and
• (b) returning a first signal in response to the data type indicator bit, wherein the first signal is representative of a data type of the sector of the optical disc;
• and
• (c) adjusting a size of a data field in a buffer memory based upon the returned first signal.