Reading Audi LIN BUS

#1

Hi all!

My name is Eero and im from Finland. I studying in electric automation engineer specialized to programming. I am at first year and it taks 3-4 years to graduate.

I have done some retrofits to my previous Audi A4 2009, but now i am learned programmin mostly Python and C# i realized what nice things i can do to my car.

I have changed new steering wheel from Audi TTS mk2 to my Audi A7 2011. Airbag problem was solved easily with R8 airbag with two detonators but problem is buttons. TTS steering wheel have two buttons more than in A7.

I do not know is that TTS with newer LIN BUS system than A7, or is those buttons giving just different signals and A7 does not understand them. Any of those buttons working, just lights are working but they coming from + and ground.

Anyways, i want to read the LIN BUS signals of the buttons. Can i do it with Macchina m2?

I have to read what TTS SW buttons giving and what A7 SW is giving. So i can translate TTS signal to A7.

How can i do that, is not clear yet. I have to program some microprocessor module to translate one code to another, LIN wire which is coming from steering wheel have to go trough that module.

Is there anyone who having experience with this?

#2

I do not have a great deal of experience with this, but the M2 does have the hardware for LIN.
https://docs.macchina.cc/m2-docs/detailed-reference/interfaces

Here’s an article that might help
https://gm-techlink.com/?p=11835

#3

I read all info of those, but still do not have answer for the problem is m2 able to read Audi A7 LIN. There is transceivers and LIN inputs so it should work, question is, does it support that version of LIN.

I just do not want to spent $100 as a student with low monthly income if it’s not working :smile:

#4

If you look at the M2 schematics, it uses a TJA1027 for LIN.
If we look at the TJA1027 data sheet:
“It is primarily intended for in-vehicle sub-networks using baud rates up to 20 kBd … The TJA1027 is fully LIN 2.0, LIN 2.1, LIN 2.2, LIN 2.2A, SAE J2602 and ISO 17987-4:2016 (12 V) compliant. The LIN physical layer is independent of higher OSI model layers (e.g. the LIN protocol). Consequently, nodes containing an ISO 17987-4:2016 (12 V) compliant physical layer can be combined, without restriction, with LIN physical layer nodes that comply with earlier revisions (LIN 1.0, LIN 1.1, LIN 1.2, LIN 1.3, LIN 2.0, LIN 2.1, LIN 2.2 and LIN 2.2A).”

As for what your Audio has, I have no idea. You will have to search Google or some Audi forums.

But it sounds like the xcvr supports the latest revision, and it’s backwards compatible, so it should work.

#5

I think my Audi do not have over 2.1 LIN. I’ll make an order of Machina m2.