2 months ago
- The Amiga floppy controller uses four separate chips instead of a single integrated controller like the NEC765.
- Two 8520 CIAs handle control I/O: the odd CIA manages outputs from the drive (disk sensing), and the even CIA manages inputs to the drive (selection, control, stepping).
- Gary handles motor control and write data, processing signals from Paula through a NAND gate inverter.
- Paula processes read data, performs DMA, and includes a hardware digital PLL for data separation; it does not handle drive selection or motor control.
- MFM encoding/decoding is handled in software by the trackdisk.device in Kickstart ROM.
- The author found detailed patents for Paula's DPLL (US patent 4780844) and Paula itself (US patent 4829473), revealing hardware-based data separation.
- The Amiga's approach is more software-heavy than PC controllers, offering greater flexibility.