Amiga Hardware DatabaseManufacturer Byte by Byte, USA | Date 1987 | Amiga A1000 | Interface Zorro I |
- SCSI and ST-506 controller
- ST-506 hard disk controller card with a SCSI option, offered as an option for the PAL & PAL Jr. expansion chassis
- card conforms to the Zorro I standard and could therefore be used in other expansion chassis if mechanically fitting
- based on a Commodore design, it is electrically identical to the Commodore A2090 controller card - except for the SCSI part, which was not completely finished at the time
- the SCSI drives are controlled by the WD 33C93 IC
- the ST-506 drives are controlled by the Zilog Z80B CPU
- the 33C93 chip can be controlled by either the 68000 (default) or by the Z80
- DMA transfers are provided by the custom Commodore (MOS) 8727 IC featuring a 64 byte FIFO buffer
- the Z80 CPU has 2 kB RAM to buffer commands from the Amiga, 8 kB PROM with driver routines and 1 kB RAM for storage of variables
- cannot autoboot
- does not support the RDB standard and the SCSI Direct protocol
- does not support partitions and drives larger than 256 MB
- the ST-506 interface does not support 16-head drives
- with SCSI option: 50 pin internal SCSI connector, DB25 external connector
- C²-ML (or C2-ML) marking on the PCB denotes the board technology (copper clad multi-layer) and is often mistakenly understood as expansion name
w/o SCSI option, front side
w/o SCSI option, back side