1-wire Lowspeed CAN in the Astra J

Hi!

I hope someone can help me here.
I've been using an Arduino with a CANdiy shield in my Vectra C for a while now, and I wanted to use a similar setup in my Astra J, or at least initially just to sniff the CAN bus.
Since the data I'm looking for isn't available in the Midspeed CAN, I'm hoping to find it in the Lowspeed CAN. If things go badly, I'll probably only find it in the LIN bus, which would be completely new territory for me. Basically, the original radio needs to be replaced, which means the config button that allows for various vehicle settings will be missing. That's not ideal, so I want to create something to compensate for it.
But let's leave that aside for now; let's get to the real issue:

The LS-CAN is a 1-wire CAN. If I haven't completely misunderstood, I should connect CAN-H to pin 1 (SW-LS-CAN (33kB)) on the OBD connector and CAN-L to the car's ground? The thing is, as soon as I do that, the control units start acting up, and I get a bunch of error messages on the dashboard display. So, I'm probably cutting off the communication between the control units and the display?

What am I probably doing wrong? Does anyone have any ideas?

/edit: OK, it seems the built-in MCP2562 probably doesn't support 1-wire communication. Hmm... but could that be the reason why the communication in the LS-CAN is being disabled?

Hi,

Are all potential scheduling conflicts resolved, and is "Listen Only" mode active?

Best regards, Rainer.

Appointment scheduling resistance is resolved.
And it's "Listen Only" in the sense that I don't actively send anything from my code myself.

Well, one thing I did notice, as you can see from my edit above.

Quote:

/edit: OK, the built-in MCP2562 probably doesn't support 1-wire. Hmm... but could that be the reason why the communication in the LS-CAN is being disabled?

The TJA1055 can operate not only with standard low-speed CAN, but also in single-wire mode.

Quote:

The TJA1055 is the interface between the protocol controller and the physical bus wires in. a Controller Area Network (CAN). It is primarily intended for low-speed applications up to... 125 kbps in passenger cars. The device provides differential receive and transmit capabilities. capability, but will switch to a single-wire transmitter and/or receiver in error conditions. The TJA1055 is the enhanced version of the TJA1054 and TJA1054A.

Best regards, Rainer.

Thank you.

Do you think the TJA1054T will work too?
It's quite difficult to obtain a TJA1055 .

Yes, the TJA1054 can essentially do the same thing (previous model, differences mainly in ESD protection, 3V interface, and wakeup), and both cost less than 2 EUR for single units. However, I must admit that it may be difficult for private individuals to obtain them. Most electronics retailers that supply businesses carry those products.

Best regards, Rainer.

Okay, I've obtained the TJA1055 and MCP2515, connected them on a breadboard, tested them on my Vectra, and...: The same phenomenon occurs. As soon as I connect it, I get a "disco" effect in the speedometer. I have no idea what I'm doing wrong .
Midspeed, on the other hand, is running perfectly fine with the test setup.

Any ideas?

/Edit: Oh, I'm going crazy. A typo in the CNF values was the culprit. I wasn't aware that this could trigger something like that .

"Stuff happens." I really appreciate that you're giving feedback about what caused the issue!