Specifications

2.2 Connector used on 2.5-inch drives
The ATA connector on 2.5-inch drives has 50 pin positions. In addition
to the key pin, one pair of pins is removed, and the four end pins are used
as jumpers for master/slave configurations, as shown in Figure 4. This
leaves 44 pins to supply power and conduct signals to and from the drive.
The signal pins (1 through 40) are assigned the same signals as in the
40-pin connector used for 5.25- and 3.5-inch drives. Power is supplied
through pins 41, 42 and 43. The mating cable connector is a 44-conductor
nonshielded connector with 2 rows of 22 female contacts on 0.079-inch
(2 mm) centers, as shown in Figure 5 on page 6.
Pin
A
C
1
3
5
7
9
11
13
15
17
19
21
23
25
27
29
31
33
35
37
39
41
43
Pin
B
D
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
Signal / use
master/slave jumper
master/slave jumper
no pin
Ground
DD8
DD9
DD10
DD11
DD12
DD13
DD14
DD15
key (no pin)
Ground
Ground
Ground
SPSYNC:CSEL
Ground
IOCS16–
PDIAG–
DA2
CS3FX–
Ground
+5V (motor)
Type
Signal / use
master/slave jumper
master/slave jumper
no pin
RESET–
DD7
DD6
DD5
DD4
DD3
DD2
DD1
DD0
Ground
DMARQ
DIOW–
DIOR–
IORDY
DMACK–
INTRQ
DA1
DA0
CS1FX–
DASP–
+5V (logic)
+Ground
Figure 4. Pin assignments for the 50-pin male ATA interface connector
used on 2.5- and 1.8-inch drives
ATA Interface Reference Manual, Rev. C 5