ACSI (Atari Computer System Interface) is a SCSI-derived bus on the Atari ST using a DB19 connector for hard drives, CD-ROM drives, and the SLM804 laser printer from 1985 to 1994.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | D0 | Data bit 0 | I/O |
| 2 | D1 | Data bit 1 | I/O |
| 3 | D2 | Data bit 2 | I/O |
| 4 | D3 | Data bit 3 | I/O |
| 5 | D4 | Data bit 4 | I/O |
| 6 | D5 | Data bit 5 | I/O |
| 7 | D6 | Data bit 6 | I/O |
| 8 | D7 | Data bit 7 | I/O |
| 9 | /CS | Chip select active low | I/O |
| 10 | GND | Ground | GND |
| 11 | A1 | Address bit 1 | I/O |
| 12 | /IRQ | Interrupt request | I/O |
| 13 | /DRQ | DMA request | I/O |
| 14 | /DACK | DMA acknowledge | I/O |
| 15 | R/W | Read write direction | I/O |
| 16 | /RST | Reset | I/O |
| 17 | GND | Ground | GND |
| 18 | GND | Ground | GND |
| 19 | +5V | 5V power | PWR |