CDFS Technical Details
CDFS
» CDFS Technical Details
CDFS Technical Details
CDFS Control Block
Data Modes
The following table details the different data modes that CDFS currently understands.
| Mode | Meaning |
|---|---|
| 0 | Audio |
| 1 | Data Mode 1 |
| 2 | Data Mode 2 format 1 |
| 3 | Data Mode 2 format 2 |
Addressing Mode
Addresses have different meaning depending on the addressing mode:
| Mode | Meaning |
|---|---|
| 0 | Logical block addressing (Offset in blocks from the start of a CD’s data area) |
| 1 | Red Book addressing (A time offset from a CD’s first frame, in the form detailed below this table) |
| 2 | Physical block addressing (offset in blocks from the first block on the CD) |
Red Book Addressing Details
| Byte | Label | Meaning |
|---|---|---|
| 0 | FF | Frame number (0 – 74) (75 frames in one second) |
| 1 | SS | Seconds (0-59) |
| 2 | MM | Minutes (0-99) |
| 3 | Reserved |
CDFSDriver assumes that all discs have a lead-in period of 2 seconds (150 blocks). The CD_ConvertToLBA and CD_ConvertToMSF SWIs know to apply this offset; the conversion is such that LBA 0 and MSF 00:00:00 both correspond to physical block 150. Attempting a mode 0 or mode 1 access to addresses below physical block 150 may result in an error.
CD Drive Status
| Value | Meaning |
|---|---|
| 1 | OK |
| 2 | Busy |
| 4 | Not Ready (e.g. Drive empty) |
| 8 | Unavailable |
16 Byte Track Block
The following block is used by CD_SetParameters and CD_GetParameters.
| Offset | Contents |
|---|---|
| 0 | Log spin-down delay 0-15 (0 equivilent to 16, 1 = shortest) |
| 4 | Number of retries |
| 8 | Read mode (0, 1 and 3 for data, 2 for audio) |
| 12 | Speed in multiples of ‘standard’ speed |
See also
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