Re: Adapter | Posts 16+

Nicklas wrote:

In all the adapters I've seen so far, there was also a 100 Ohm resistor in the GND line, which makes the optocouplers completely pointless.

Hi Nick,

Regarding my designs (currently version 2.4), the adapter would also function correctly without the 100-ohm resistor. They are only there to channel any potential static charges and allow them to dissipate in a controlled manner.

In Maik's adapter (and similar circuits), it is also needed in addition to signal coupling.

Hi,

I haven't seen your 2.4 adapter yet. Could you send me a schematic diagram?

Nick.

@ulf

It took forever, but...
I have replicated your adapters 2.4 and 2.5. The result is almost exactly the same as described in my other threads: gas surges, etc.! If I change the basic settings of VAG-COM to the values like in Maik's adapter, then it works! By the way, Jeff's original adapter also worked for me yesterday with modified settings .

Okay, so I'm even more convinced now that the Dino-STG isn't adhering to the protocol, and VAG-COM can't handle these bit length fluctuations. A proper handshake could help. Unfortunately, the STG doesn't have a handshake line!

Nicklas wrote:

I haven't seen your 2.4 adapter yet, could you please send me a schematic?

Hi Nick,

You can find the plan in the "Diagnostic Adapter" article, in the "Tips & Tricks" folder on Rainer's website.

joergs wrote:

I have replicated your adapters 2.4 and 2.5. The result is almost exactly the same as described in my other threads: gas surges, etc.! If I change the basic settings of VAG-COM to the values like in Maik's adapter, then it works! By the way, Jeff's original adapter also worked for me yesterday with modified settings . Okay, so I'm even more convinced now that the Dino control unit isn't adhering to the protocol, and VAG-COM can't handle these bit length fluctuations. A proper handshake could provide a solution. Unfortunately, the control unit doesn't have a handshake line!

Hi Jörg,

one more puzzle piece in the dialogue riddle...

Regarding the handshake process: Couldn't such a signal be artificially generated by running the data stream from the car through a specially programmed processor?

Just as a spontaneous question without any specific professional background - if it's nonsense, please excuse me .

@ulf

'That could be a possibility, but you'd still have the bit length difference. The handshake is just a way for the RS232 to say, 'I'm ready to receive,' and then the control unit (STG) sends the data. If the RS232 says, 'I'm currently busy,' the STG has to wait! That should be possible to implement. However, if you're going to do that, you should also fix the bit length issue at the same time, which I think would be more difficult. You'd run into the problem of sampling again. And that brings us back to the VAG-COM problem. Apparently, even Meister Ross doesn't have a solution for that!'
If you want to make an RS232 connection truly waterproof, you should send a control signal from one side for synchronization and also use a handshake protocol. This ensures a very reliable connection, but the device must also support these protocols.

I've experimented with RS232 myself and tried out some programming. You can monitor and/or control the handshake lines in real-time or near real-time from Windows. Unfortunately, it's not that simple with the data lines. I had the idea of simply connecting the K-line and L-line to the handshake lines and creating a program around it to have my own diagnostic tool. However, I can't access the protocol to communicate with the control unit (ECU) and back. If I had that, I think it would be possible to program something similar to a VAG-COM in a relatively short time, and perhaps avoid these problems.

Okay, here's my question for this group: Does anyone have knowledge of the protocols, or can anyone obtain the relevant documents?