CompactFlash Card Pinout

True IDE Mode

CompactFlash, Pin Out

CompactFlash uses a 50-Pin connector [2 rows of 25 pins]. The 50-pin connector is on 50-mil centers [1.27mm].
Pins 1 to 25 are located on the row near the key, and pins 26 to 50 are located in the row above that.

CF Pinout Location and Connector Layout

Active low signal use a '-' prefix. The CompactFlash card operates in one of three modes. The function of some of the pins change with each mode.
The three modes are PC Card ATA using I/O mode, PC Card ATA using Memory mode, and True IDE mode compatible with most IDE drives. This page lists the True IDE mode pinout.
Refer to these pages for additional pin out styles of CompactFlash.
PC Card Memory Module Pinout
PC Card I/O Mode Pinout
The main CompactFlash page.

CF True IDE Mode Pinout
Pin # Signal Function Pin Type In, Out Type
1 GND - Ground
2 D03 I/O I1Z, 0Z3
3 D04 I/O I1Z, 0Z3
4 D05 I/O I1Z, 0Z3
5 D06 I/O I1Z, 0Z3
6 D07 I/O I1Z, 0Z3
7 -CS0 I I3U
8 A10 I I1Z
10 A09 I I1Z
11 A08 I I1Z
12 A07 I I1Z
13 Vcc - Power
14 A06 I I1Z
15 A05 I I1Z
16 A04 I I1Z
17 A03 I I1Z
18 A02 I I1Z
19 A01 I I1Z
20 A00 I I1Z
21 D00 I/O I1Z, OZ3
22 D01 I/O I1Z, OZ3
23 D02 I/O I1Z, OZ3
24 IOCS16 O OT3
25 -CD2 O Ground
26 -CD1 O Ground
27 D11 I/O I1Z, OZ3
28 D12 I/O I1Z, OZ3
29 D13 I/O I1Z, OZ3
30 D14 I/O I1Z, OZ3
31 D15 I/O I1Z, OZ3
32 -CS1 I I3U
33 -VS1 O Ground
34 -IORD I I3U
35 -IOWR I I3U
36 -WE I I3U
38 Vcc - Power
39 -CSEL I I2Z
40 -VS2 O Open
43 RFU O OZ1
44 RFU I I3U
45 -DASP I/O I1U,ON1
47 DO8 I/O I1Z, OZ3
48 DO9 I/O I1Z, OZ3
49 D10 I/O I1Z, OZ3
50 GND - Ground

True IDE mode only uses A0 - A2; Pins 8, 10, 11, 12, 14, 15, 16 and pin 17 are grounded at the Host.
True IDE mode does not use this line; Pin 36 should be tied to Vcc at the host.
True IDE mode does not use this line; Pin 44 should be held high or tied to Vcc at the Host.

PC motherboard

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Modified 6/13/15
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