Hard Disk Pinout -- Laptop and Desktop -- ATA or IDE

1 Hard Disk Pinout -- Laptop and Desktop -- ATA or IDE

Here is the pin assignment for the ATA (also known as IDE) interface for the hard disk in a portable computer (laptop or notebook). The pinout for a desktop is the same, but uses only the first 40 pins. Also beware that the laptop connector is mechanically different: the pins are more closely spaced, as compared to the desktop connector. This makes it harder than you might have guessed to attach a laptop-style disk to your desktop machine ... although it is certainly possible to make or buy an adapter.

pin     assignment      pin     assignment
1       -Reset          2       GND
3       Data 7          4       Data 8
5       Data 6          6       Data 9
7       Data 5          8       Data 10
9       Data 4          10      Data 11
11      Data 3          12      Data 12
13      Data 2          14      Data 13
15      Data 1          16      Data 14
17      Data 0          18      Data 15
19      GND             20      Key (no pin)
21      (reserved)      22      GND
23      -IOW            24      GND
25      -IOR            26      GND
27      IO Chrdy        28      Ale
29      (reserved)      30      GND
31      IRQ14           32      -IOCS16
33      Addr 1          34      (reserved)
35      Addr 0          36      Addr 2
37      -CS0 (1F0-1F7)  38      -CS1 (3f6-3f7)
39      -Active         40      GND 
41      +5VDC (logic)   42      +5VDC (motor)
43      GND             44      Type (0==ATA)

The disks are male; the cables are female. Pin 1 is traditionally on the top side (i.e. label side) of the disk, on the right as you face the drive, as marked with a ``v'' in the diagram below.

2 Master/Slave Jumpers

For desktops (40 pin connector) the master/slave jumper pinout is definitely nonstandard; check your disk to see if the scheme is printed on it. Otherwise track down the documentation for your disk.

For laptops (44 pin connector) the master/slave jumper scheme given below seems to be pretty common, although I wouldn’t be surprised to find others. Looking at the pins, we have:

			 v
    ...................... ..  device 0
    ............ ......... ..  i.e. master

			 v
    ...................... .|  device 1
    ............ ......... .|  i.e. slave

			 v
    ...................... ..  cable select
    ............ ......... ==

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