Decoding date and time

Hi!

First of all: This is my first CAN bus project (and also my first Arduino project), so please be patient .

I am currently in the process of integrating an Android tablet into my Vectra C (which has a CID) and, for the best possible integration, in addition to features like displaying the title (which already works) etc., I also want the tablet to synchronize the date and time with the OEM display.

I've already recorded and compared the messages before, but I just can't seem to identify the correct "pattern" in them.

Here's what I recorded from the CD70 (which is the original equipment head unit). On the right, you'll see the timestamps indicating when each message appeared. The messages generally only appeared at the start of each minute.

Code:

ID:458 D3 92 45 21 BE 63 56 04   | 25.04.2015 23:24 ID:458 D3 92 45 21 BE 63 56 44   | 25.04.2015 23:25 ID:458 D3 92 45 21 BE 63 56 84   | 25.04.2015 23:26 ID:458 D3 92 45 21 BE 63 57 44   | 25.04.2015 23:29 ID:458 D3 92 45 21 BE 63 58 84   | 25.04.2015 23:34 ID:458 D3 92 45 21 BE 63 5A 04   | 25.04.2015 23:40 ID:458 D3 92 45 21 BE 63 5A 84   | 25.04.2015 23:42 ID:458 D3 92 45 21 BE 63 5A C4   | 25.04.2015 23:43 ID:458 D3 92 45 21 BE 63 5B 04   | 25.04.2015 23:44 ID:458 D3 92 45 21 BE 63 5B 44   | 25.04.2015 23:45 ID:458 D3 92 45 21 BE 63 5D 84   | 25.04.2015 23:54 ID:458 D3 92 45 21 BE 63 5D C4   | 25.04.2015 23:55 ID:458 D3 92 44 21 BE 63 60 04   | 26.04.2015 00:00 ID:458 D3 92 44 21 BE 63 61 44   | 26.04.2015 00:05 ID:458 D3 92 45 41 BE 63 61 84   | 26.04.2015 00:06 ID:458 D3 92 45 41 BE 63 61 C4   | 26.04.2015 00:07 ID:458 D3 92 45 41 BE 63 62 04   | 26.04.2015 00:08 ID:458 D3 92 45 41 BE 64 C3 84   | 26.04.2015 14:14

The difference between one minute is usually converted to decimal: 64. But between 23:55 and 0:00, I expected a difference of 320, but instead it is 576 .

"By the way, I also modified some messages and re-transmitted them over the CAN bus, and the following result was obtained, for example:"

Code:

D3 92 45 21 A9 71 2C 44   | 22.12.2007 20:49 D3 92 45 21 A9 72 2C 44   | 23.12.2007 04:49 D3 92 45 21 A9 73 2C 44   | 23.12.2007 20:49 D3 92 45 21 A9 74 2C 44   | 24.12.2007 04:49

What follows is, of course, what resulted from the process.

Does anyone recognize the pattern?! I'm completely lost.

Regards,
Sven.

Welcome.

Quote:

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Okay, I understand. Please provide the German text you want me to translate. I will then provide the English translation as a file attachment in this thread.

I'll take a look at the ID afterwards.

Best regards, Rainer.

It's a video and doesn't really contribute much to the topic. It just shows how far I've gotten

Code:

ID:458 D3 92 45 21 BE 63 5A 04   < 25.04.2015 23:40  0101 1010 0000 ID:458 D3 92 45 21 BE 63 5A 84   < 25.04.2015 23:42  0101 1010 1000 ID:458 D3 92 45 21 BE 63 5A C4   < 25.04.2015 23:43  0101 1010 1100 ID:458 D3 92 45 21 BE 63 5B 04   < 25.04.2015 23:44  0101 1011 0000 ID:458 D3 92 45 21 BE 63 5B 44   < 25.04.2015 23:45  0101 1011 0100 ID:458 D3 92 45 21 BE 63 5D 84   < 25.04.2015 23:54  0101 1011 1000 ID:458 D3 92 45 21 BE 63 5D C4   < 25.04.2015 23:55  0101 1101 1100 ID:458 D3 92 44 21 BE 63 60 04   < 26.04.2015 00:00  0110 0000 0000

.

I've made a little more progress by looking at the whole thing in binary (the idea just came to me a few minutes before the end of the workday).
If I split the bytes and omit certain bits, I get the correct differences. I just need to figure out how they are exactly composed.



The binary refers to these locations:
D3 92 45 21 BE 63 5A 0}4.

When was your Vectra manufactured?

Possibly, the time is calculated in seconds starting from January 1, 2000, with 0x80 being subtracted from byte 4 (first byte: 0).

September 2007.

In my opinion, there are no seconds involved in the transmission process.

I have found the 'minute block' and can reproduce it. The rest seems to be a 'hours since' value, if I understand correctly. I am still puzzling and experimenting .

I have achieved my desired result .

Cool stuff, congratulations!

Hi,

I think the project you're working on is really great! I'm currently replacing the CD30MP3 in my Vectra C with...
Since I replaced the double-DIN receiver, I'm now also experiencing the annoying problem with the date and time.
I would appreciate it if you could help me understand how the date and time are encoded here.
and how they can be implemented via CAN. I have a CAN interface available. I'm looking for a solution.
from a small microcontroller (AVR or STM32) with a cheap GPS module attached. This could then independently determine the time.
Sure, here is the translation of the text from German to English:

'stellen.'

'to place' or 'to set'

Best regards,
Marco.

Hi!

So, basically, everything is explained above .

"In my opinion, you can always use 'D3 92 45 21' for the first 4 bytes. While the OEM head unit sometimes varies, I haven't yet understood why. However, the above works for me every time."

You can see how the other 4 bytes are structured in my handwritten notes in the image in my previous post. The time appears to be based on UTC.

Regards,
Sven.

Hi,

I completely overlooked the image with the bit assignment . That certainly helps.
Have you ever looked at the protocol used to transmit the text to the display?

Regards,
Marco.

Yes, as you can see in the video above, it's not only possible to transfer text, but also to create your own menus to a certain extent .

However, explaining all of this would take quite a while, especially since I haven't fully understood the news myself yet.

Just listen to IDs 6C1 and 2C1.

To simulate a radio that is turned on, you should send a signal once every 2-3 seconds.
"41 00 60 0C 82 00 02 2A" on ID 691.