SH7263 Datasheet, PDF (1171/1862 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7260 Series

Section 21 CD-ROM Decoder (ROM-DEC)
(4) Interpolated Sync Plus External Sync Mode
In interpolated sync plus external sync mode, synchronization is based on the detected sync code
patterns as long as they are present, and if a sync pattern is not detected at the 2352nd byte, the
sync code maintenance is applied. Synchronization in this mode is more quickly responsive to
changes in synchronization timing than synchronization in the automatic sync maintenance mode.
However, decoding still becomes incorrect when a sync pattern is input with abnormal timing.
Figures 21.13 and 21.14 show the operation in interpolated sync plus external sync mode in the
cases of abnormally short and long sectors, respectively.
Input data
Sync code
detection
Abnormal sector
Sector 1
Sector 3
Sector 4
Sector 5
Sector 6
Maintain
Output data
Sector 1
Sector 3
Sector 4
Sector 5
Abnormal
sector
Figure 21.13 Operation in Interpolated Sync Plus External Sync Mode
(When an Abnormally Short Sector is Encountered)
Input data
Sector 1
Abnormal sector
Sector 3
Sector 4
Sector 5
Sync code
detection
Maintain
Output data
Sector 1
Sector 3
Abnormal Abnormal
sector
sector
Sector 4
Figure 21.14 Operation in Interpolated Sync Plus External Sync Mode
(When an Abnormally Long Sector is Encountered)
Rev. 2.00 Mar. 14, 2008 Page 1137 of 1824
REJ09B0290-0200