[Viscouse]

OK, I was wondering with the various discussions that have been had regarding steering wheel controls...
Does anyone know where a good place to get an i-bus signal from? I think there's some available pins in the back of the EHU but I can't remember where I saw that.

I want to try and get this thing working:
http://www.reslers.de/IBUS/
It's designed to accept a CD changer cable for a BMW (which operates on the i-bus)

 

[epsilon93]

This is very interesting. Certainly something that is worth hacking. I am pretty sure you can find I-BUS signals at the EHU harness. You can also find them on the CMU. I'll have to look at the WIS to be sure. I know for sure that the I-BUS is available on the dashboard control where the TCS/ESP switches are.

 

[Viscouse]

That correllates with my research as well. I was thinking of easier access: the ACC panel.

In any case, I think splicing wires will be in order. I was hoping to find a blank plug (I think there's one in the engine compartment, but I also think it's for deisel only).

I have a couple emails in to the inventor, we'll see what he says.
Only problem is that it's an RS232 serial, meant for a computer. All well & good if you're putting in a carputer, but what if you want to just decode signals.

So many possibilities. I smell our next great challenge! And it smells like Victory!

(I hope)

 

[epsilon93]

It can still be done by interfacing the signals directly to a microcontroller like a PIC. Then you just need to write a bit of software to decode the signals and use it to control whichever device you need. I am assuming you are just trying to decode and not send any signals to the car I-Bus. Now I am wondering if the SID is I-Bus controlled. Hmmmmmm....... it could mean sending song name and text to the SID. Hmmmm.......

 

[Viscouse]

Why Yes, yes it is! You can see all the devices on the I-Bus here:
http://www.saabcentral.com/forums/showthread.php?t=18142

I kinda figured: step1 is decoding, & step 2 is encoding. You can them FINALLY have something that will also tell the Stereo to go to Aux on default when the car starts.

 

[Viscouse]

So I see that some modules have 2 ibus leads, and some just 1. I assume it's for incoming & outgoing signal.
Take for instance the SPA. It has 1, and it should transmit only. It transmits info that it computes, and doesn't need any feedback.

Now the ACC (which has 2 ibus leads), transmits info & receives info. I wonder if the device above (since it has only 1 ibus input) can only decode transmits? I wonder if another one placed on the receive line will be able to allow the car to receive commands.

Rolf's info:

Pinout for that 4-pin connector:
pin1: IBUS
pin2: 12V
Pin3: Ground
pin4: NTSC switch (not used)

Also, the device doesn't "decode" anything, it simply translates from ibus to RS232. So in essence, the laptop/carputer would look like another module on the bus. It should only need 1 lead.

 

[epsilon93]

As fas as I know, I-BUS is a single wire communication system, like 10-BASE-2, it has the ability to detect collisions and will avoid collisions when it has data to transmit hence it is listening to the bus all the time. I am not sure why there are 2 bus wires going into some of the units. Hmmm.....

 

[Viscouse]

More info I've unearthed...
P-bus=500 kbits/s
I-bus=33 kbits/s
They're both part of the CAN.

Here is also another possible tool to use:
http://www.kvaser.se/
Maybe the Kvaser Leaf Light HS would work.

There's Bus analyser software too!

 

[spctm]

More info I've unearthed...
P-bus=500 kbits/s
I-bus=33 kbits/s
They're both part of the CAN.

Here is also another possible tool to use:
http://www.kvaser.se/
Maybe the Kvaser Leaf Light HS would work.

There's Bus analyser software too!

Resurrecting this thread from the ashes. Has anyone tried to connect to I-bus so far. I have been looking at building a head unit with raspberry pi 2 and was wondering how to interface with steering wheel control and also the various bus'es (canbus, i-bus). I came across http://www.carberry.it/ which is a raspberry pi shield and can communicate with various cars over canbus/gmlan etc. Saab 93 and 95 are also listed in car compatibility list. I have no prior experience with bus level programming, so if anyone has any prior experience I would love to get some inputs.

 

[spctm]

Resurrecting this thread from the ashes. Has anyone tried to connect to I-bus so far. I have been looking at building a head unit with raspberry pi 2 and was wondering how to interface with steering wheel control and also the various bus'es (canbus, i-bus). I came across http://www.carberry.it/ which is a raspberry pi shield and can communicate with various cars over canbus/gmlan etc. Saab 93 and 95 are also listed in car compatibility list. I have no prior experience with bus level programming, so if anyone has any prior experience I would love to get some inputs.

Just a small update.

I-bus = GMLAN = Single Wire CAN, operates at 33.3Kbps
P-bus = differential CANbus, operates at up to 500 Kbps (but potentially up to 1Mbps in many other CANBUS implementations).

I am planning to integrate SingleWireCAN (I-bus/GMLAN) into a DIY Android headunit. This is what I have got so far.

Use a Teensy 3.1 or Arduino board to connect to a swcan transceiver (e.g MC33897CTEF-ND or NCV7356D1GOS-ND) to constantly read over the bus. I can then receive messages over this bus and take actions based on certain events. A separate canbus transceiver connected to another arduino can be used to connect to canbus (P-bus) for listening to engine/transmission related information. However, my current bluetooth OBDII device already does this with android.

If anyone has any information regarding GMLAN/SWCAN/I-bus messages please do share. If not I'll take some time to sniff them at some point.

 

[Griffinous]

Just a small update.

I-bus = GMLAN = Single Wire CAN, operates at 33.3Kbps
P-bus = differential CANbus, operates at up to 500 Kbps (but potentially up to 1Mbps in many other CANBUS implementations).

I am planning to integrate SingleWireCAN (I-bus/GMLAN) into a DIY Android headunit. This is what I have got so far.

Use a Teensy 3.1 or Arduino board to connect to a swcan transceiver (e.g MC33897CTEF-ND or NCV7356D1GOS-ND) to constantly read over the bus. I can then receive messages over this bus and take actions based on certain events. A separate canbus transceiver connected to another arduino can be used to connect to canbus (P-bus) for listening to engine/transmission related information. However, my current bluetooth OBDII device already does this with android.

If anyone has any information regarding GMLAN/SWCAN/I-bus messages please do share. If not I'll take some time to sniff them at some point.

Sorry to resurrect a 5 year old post, but did you ever complete this project? I am finding it extremely difficult to find a canbus interface for the 9-3 (2003-2006)

 

[aerojon]

this thread is 15yrs old..They've not logged in for over 18months.doubt you'll get a reply

 

[Griffinous]

this thread is 15yrs old..They've not logged in for over 18months.doubt you'll get a reply

I'm hoping I will, no one seems to know anything about canbus decoding this car's steering wheel controls

 

[Hus_sho]

If u have steering shifts u cannot find any canbus interface .. if u dont have these u might be lucky to find them if they r still in the market, last time ive seen one of these probably 10 years ago

 

[okcrum]

I'm hoping I will, no one seems to know anything about canbus decoding this car's steering wheel controls

CANBus is well-defined, but GM's messaging protocol atop it is not. Here is a current atttempt to reverse engineer it.

 

[okcrum]

Here is someone sniffing the single wire CANBus (I-bus in Saab).

Eavesdropping on the Single Wire CAN Bus – Part 4: GMLAN (Holden VE Commodore SWCAN).

 

[Griffinous]

That was an interesting read, although I do note that it's a completely different system. I believe the 2003-2006 9-3 uses a 2 wire canbus loop back system

 

[okcrum]

Saab uses (for all NG 9-3 model years) 500 kbps 2 wire CANBus for driveline (P bus) and 33 kbps 1 wire CANbus for instrumentation (I bus). 2003-2006 uses a fiber optic ring for the audio system with ISM as a gateway. 2007-2012 uses subnet of I bus for audio/communication with BCM as gateway.

 

[Griffinous]

You're way more technical than I am. All I know is that no one has done a how-to guide on how to make a simple canbus interface for this car

 

[okcrum]

Nope. You'd use the sniffer in the article to see the messages from the CIM when you push buttons on the steering wheel. That's what the aftermarket audio people have done, I imagine. The messages might already be in the GMLAN protocol spreadsheet (linked above & below). Then you'd just need to have your controller with CANBus interface speak and listen to the right things on the bus.

GMLan_Bible