CD32 CD-ROM Subsystem
Here is some information on the internal drive of the CD32.
This information comes from the CD32 service manual.
A separate PCB (2 layer) contains the CD electronics. This board contains the RF amp and servo chip, the audio DSP chip, and a small microcontroller for controlling the servo, focus, and communicating with the main CPU. The main CPU and RAM perform any prefetching/ buffering and ECC as necessary.
The mechanism for the Amiga CD32 is a Sony KSM-2101BAM. The KSM-2101BAM has no drawer, or drawer motor. It is simply a spindle motor, traverse motor, and optical pickup. Chinon will provide the drive PCB. The electronics are based on the Sony CD chipset, which support double-speed operation. The microcontroller firmware has changed slightly in this version of the drive to (1) remove the firmware to control the drawer, and (2) revise the communications protocol to use a new 3-wire channel instead of the older 6-wire channel (to save pins on the ASIC) and (3) support multi-session discs (which is useful for PhotoCD support).
The software driver for the CD subsystem has been converted to run entirely on the 68EC020. The software also supports Akiko and its new DMA. This driver incorporates all the prefetching tricks and double-speed support completely from the 68EC020. It also supports both Mode 1 and Mode 2 (Form 1 and 2) discs. This is required to read all types of CD media called out in the Philips Yellow Book. This includes CD-I discs, PhotoCD® discs, and MPEG discs.
Updated 08 July 2017