Specifications

2.0 ATA cables and connectors
The standard ATA interface cable is a 40-conductor nonshielded cable. The
cable should be no more than 18 inches (457 mm) long, with connectors
that provide strain relief and are keyed at pin 20. Two types of connectors
are used on Seagate’s ATA-capable drives: a 40-pin connector for 5.25-
and 3.5-inch drives, and a 50-pin connector for 2.5- and 1.8-inch drives.
2.1 Connector used on 5.25- and 3.5-inch drives
The standard connector used on 5.25- and 3.5-inch drives has 40 pin
positions in 2 rows of 20 pins each, on 100 mil (0.1 inch) centers (see
Figures 1, 2 and 3). Pin 20 is removed for keying. The mating cable
connector is a keyed, 40-pin-position nonshielded female connector with
2 rows of 20 contacts on 100 mil centers. For 5.25- and 3.5-inch drives,
power is supplied to the drive through a separate 4-conductor cable.
Seagate recommends using 40-pin connectors such as AMP part num-
ber 1-499496-0, Du Pont part number 66900-040, or equivalent.
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
Ground
DD8
DD9
DD10
DD11
DD12
DD13
DD14
DD15
key (no pin)
Ground
Ground
Ground
SPSYNC:CSEL
Ground
IOCS16–
PDIAG–
DA2
CS3FX–
Ground
Pin Pin SignalSignal
RESET–
DD7
DD6
DD5
DD4
DD3
DD2
DD1
DD0
Ground
DMARQ
DIOW–
DIOR–
IORDY
DMACK–
INTRQ
DA1
DA0
CS1FX–
DASP–
Figure 1. Pin assignments for the 40-pin male ATA interface connector
used on 5.25- and 3.5-inch drives
ATA Interface Reference Manual, Rev. C 3