(40 PIN IDC MALE)
44-pin connector at the notebook HDD
The 44-pin ATA connector is the 2.5-inch (notebook) variant of the parallel ATA interface governed by the ATA/ATAPI standards family (T13 Technical Committee / NCITS). Pins 1–40 carry the same signals as the standard 40-pin IDC header used on 3.5-inch desktop drives, with 2.54 mm (0.100 in) pin pitch and pin 20 removed for keying. Pins 41–42 add +5 V power and pins 43–44 provide ground, replacing the separate 4-pin Molex power connector required by full-size drives. This adapter maps the 44-pin notebook connector to a standard 40-pin ATA bus, making 2.5-inch drives usable in desktop systems when an appropriate power supply is provided.
| ATA 40 Pin | ATA 44 Pin | Name | Description |
|---|---|---|---|
| 1 | 1 | /RESET | Reset |
| 2 | 2 | GND | Ground |
| 3 | 3 | DD7 | Data 7 |
| 4 | 4 | DD8 | Data 8 |
| 5 | 5 | DD6 | Data 6 |
| 6 | 6 | DD9 | Data 9 |
| 7 | 7 | DD5 | Data 5 |
| 8 | 8 | DD10 | Data 10 |
| 9 | 9 | DD4 | Data 4 |
| 10 | 10 | DD11 | Data 11 |
| 11 | 11 | DD3 | Data 3 |
| 12 | 12 | DD12 | Data 12 |
| 13 | 13 | DD2 | Data 2 |
| 14 | 14 | DD13 | Data 13 |
| 15 | 15 | DD1 | Data 1 |
| 16 | 16 | DD14 | Data 14 |
| 17 | 17 | DD0 | Data 0 |
| 18 | 18 | DD15 | Data 15 |
| 19 | 19 | GND | Ground |
| 20 | 20 | key (nc) | - |
| 21 | 21 | DMARQ | DMA Request |
| 22 | 22 | GND | Ground |
| 23 | 23 | /DIOW | Write Strobe |
| 24 | 24 | GND | Ground |
| 25 | 25 | /DIOR | Read Strobe |
| 26 | 26 | GND | Ground |
| 27 | 27 | IORDY | I/O Ready |
| 28 | 28 | Device Cfg | Spindle Sync or Cable Select |
| 29 | 29 | /DMACK | DMA Acknowledge |
| 30 | 30 | GND | Ground |
| 31 | 31 | INTRQ | Interrupt Request |
| 32 | 32 | /IOCS16 | IO ChipSelect 16 |
| 33 | 33 | DA1 | Address 1 |
| 34 | 34 | PDIAG | Passed Diagnostics |
| 35 | 35 | DA0 | Address 0 |
| 36 | 36 | DA2 | Address 2 |
| 37 | 37 | /IDE_CS0 | (1F0-1F7) |
| 38 | 38 | /IDE_CS1 | (3F6-3F7) |
| 39 | 39 | /ACTIVE - /DASI - DASP | Led driver |
| 40 | 40 | GND | Ground |
| – | 41 | VCC | +5 V |
| – | 42 | VCC | +5 V |
| – | 43 | GND | Ground |
| – | 44 | GND | Ground |
Notes
Pin 20 is physically removed (keyed) on both the 40-pin and 44-pin connectors to prevent incorrect cable insertion. Pin 34 (PDIAG-/CBLID-) doubles as the cable-detect line on 80-conductor cables: it is grounded inside the blue host connector of an 80-conductor cable, allowing the host to identify cable type. The 80-conductor cable (with 40 signal conductors interspersed with 40 ground conductors) is mandatory for Ultra DMA modes 3 and above (Ultra ATA/44 and higher); its connectors are colour-coded blue (host/motherboard), grey (Device 1/slave), and black (Device 0/master). Ultra DMA transfer rates: mode 0 = 16.7 MB/s, mode 1 = 25.0 MB/s, mode 2 = 33.3 MB/s, mode 3 = 44.4 MB/s, mode 4 = 66.7 MB/s, mode 5 = 100 MB/s. Maximum cable length is 457.2 mm (18 in).
Signals
- /RESET — Active-low reset signal from host to device
- DD0–DD15 — 16-bit bidirectional data bus
- DMARQ — DMA transfer request, asserted by device
- /DIOW — I/O write strobe (also STOP in Ultra DMA)
- /DIOR — I/O read strobe (also HSTROBE in Ultra DMA)
- IORDY — I/O ready; device deasserts to insert wait states
- Device Cfg — Pin 28; used for Cable Select (CSEL) or Spindle Sync depending on drive configuration
- /DMACK — DMA acknowledge from host
- INTRQ — Interrupt request from device to host
- /IOCS16 — Indicates 16-bit I/O transfer in progress
- DA0–DA2 — 3-bit task-file register address bus
- PDIAG-/CBLID- — Pin 34; Passed Diagnostics signal (Device 1 to Device 0); also serves as cable-detect (CBLID-) on 80-conductor cables
- /IDE_CS0 — Chip select for task-file registers at addresses 1F0h–1F7h
- /IDE_CS1 — Chip select for control/status registers at addresses 3F6h–3F7h
- DASP- — Pin 39; Device Active / Slave Present; drives an activity LED and signals Device 1 presence
- VCC — Pins 41–42; +5 V supply (44-pin connector only)
- GND — Ground (pins 2, 19, 22, 24, 26, 30, 40, 43, 44)