The Mysterious CFexpress Card Specification / Pinout

It seems like CFexpress is going to replace CFast and CF card as the new de-facto DSLR storage medium, at least for Japanese camera manufacturers. The Internet kept its mouth very shut about what this CFexpress Card actually is, with specification no where to be found.

However, piecing a few separate pieces of information together, we can make up pretty much what the specification is: it’s more-or-less M.2 with non PCI-e pins removed, with a new “INS#” pin. It’s also single sided, and utilizes a PCB edge connector.

The connector looks like this:

Here’s the pin assignment table:

PINSignalI/O DirectionRequired on Media?
R/O/NC
Required on Host?
R/O/NC
Notes
1GNDRR
2PERp1OOR
3PERn1OOR
4GNDRRTie to ground if lane 1 present
5PETn1IOR
6PETp1IOR
7ReservedNCR
8ReservedNCR
9PERST#IRR
10+3V3RR
11CLKREQ#OROActive Low.
Pull-up of >5kOhm on Host
12INS#ORRActive Low.
Tie to ground on media side.
Pull-up of 100-200kOhm on Host
13REFCLK-IRR
14REFCLK+IRR
15GNDRR
16PERn0ORR
17PERp0ORR
18GNDRR
19PETn0IRR
20PETp0IRR
21GNDRR
PIN assignment / pinout. Source: http://www.farnell.com/datasheets/2815914.pdf

Host-side dimensions drawing:

(From: http://www.rego.com.tw/_admin/upload/product/rego_15562428745ngxni.pdf)

It seems trivial to make a dummy CFexpress card and just use a NVMe drive instead. Project for another day?

By Yifan Gu

aka. Frank, aka. 顾屹凡

1 comment

  1. Hi,

    Great work! I found your page when I searching CFexpress Type A Pin assignment.
    Still not found any usefull info…

    But I assume that the CFe-A Pinout is almost same as Type B from Pin9 to Pin21, not sure.

    Do you have some info for this Type A card?

    Like

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