[Info] NX Mount Protocol Summary

ihkim wrote:

This post is quick summary of NX mount protocol. About 4 years ago, I spent several months to figure out how NX body and lens communicate, and I quite close to working version of AF adapter. You can take a look youtube video clip how my work worked OK to communicate with NX body in below post.

http://www.mydiyworld.net/?p=695

Since the time, it was on hold and I have been working for DIY NX macro extension tube set project.

I posted all deatil what I figured out in my blog as below. But, unfortunately they are written in Korean. Google can translate some of them, but some posts included images.

http://www.mydiyworld.net/?cat=108

For anyone who is interested in knowing how NX mount protocal looks like, I will give you some information as good start for your interest.

This research has been made with NX10 which is quite old body. For sure, NX protocol must have become much complecated and faster.

Basic Protocol

NX protocol is based on SPI (Serial Peripheral Interface) communication. NX body is set as Master and Lens is set as Slave.

Basic Pin Out

Pin 1: SPI Clock - Body (Master) generates clock signal to syncronize SPI communition. (Normal High)
Pin 2: SPI MOSI - (Master Out Slave In) Body sends data to Lens. (Normal Low)
Pin 3: SPI MISO - (Master In Slave Out) Lens sends data to Body. (Normal High)
Pin 4: AF Tick - This line is used only when AF is performed. This tick commands lens report the lens status (AF location, moving status, etc). (Normal High)
Pin 5: Lens Data Ready - (Normal High) Lens set this line LOW when lens has data ready to send Body. Once this signal set LOW by lens, body will generate SPI Clock, and Lens will transfer prepared data with the clock signal.
Pin 6: GND. 0V
Pin 7: Power (3.3V) It is a powersource for microcontroller in Lens.
Pin 8: Power (5.0V) It is a powersource for motors in Lens (AF and Aperture motor)

That is about it for today. I am not an EE expert and it is far from my major in colledge, though.

If you are interested, I will post further information about NX protocol.

Thank you,
ILHYOUNG.

Hi Ilhyoung,

I´m definitely interested in the work you have done, impressive to say the least.

From your website it seems that you have sorted out the communication protocol between Body and lens, or do you think there still is pieces that is unknown?

For me the "dream" output from your effort and from those who have reengineered the canon EF mount would be a lens converter to be able to use EF lenses on an NX body.

The flange distance for NX is 25.5 and EF 44 mm so there should be room for some electronics to do the conversion. The Sigma SA mount also uses the EF lens protocol and has 44mm as flange distance, but it uses a version of the Pentax K-Bayonet.

A converter between NX and EF would solve the limited lens amount problem for NX system..

I recently built myself a 3dprinter and have also some experience in PCB Cad (on hobby level..) but i dont have the programming skills to pull such a project through.... however if you need anything printed or some electronics done I would be glad to help out.

Keep up the good work!

Regards

Mats