SEGA SATURN DEVELOPER'S MANUAL

5.4 Sector data format
(1) Basic format: The sector data format basically conforms to the CD-ROM XA sector format.

Figure 5.8 CD-ROM XA sector format
(2) Handling of subheader and user data (2048 bytes) (a) Subheaders other than mode 2 (header mode part is 02H) are treated as 0. (b) There is user data immediately after the header only in mode 1 (the header mode is 01H). Otherwise, mode 2 Suppose user data is in the same position as Form 1. (c) When storing user data from a device other than a CD-ROM device, it is handled in the same way as mode 2 form 1. First The 24 bytes are 0, and the user data is undefined.: (a) Subheaders other than mode 2 (header mode part is 02H) are treated as 0. (b) There is user data immediately after the header only in mode 1 (the header mode is 01H). Otherwise, mode 2 Suppose user data is in the same position as Form 1. (c) When storing user data from a device other than a CD-ROM device, it is handled in the same way as mode 2 form 1. First The 24 bytes are 0, and the user data is undefined.
(3) Conversion of absolute time from BCD to FAD: The absolute time BCD (minute: second: frame) in the header is converted to FAD using the following formula.
FAD = {(M1 × 10 + M2) × 60 + (S1 × 10 + S2)} × 75 + (F1 × 10 + F2)
[M1 M2 S1 S2 F1 F2]: Absolute time BCD (6 digits, 3 bytes)
Absolute time is always converted using the above formula without checking the correctness of the value.

5.4 Sector data format