[CAN-FD] Vehicle Diagnostic Communication Part 95 [ISO-TP 3]

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https://www.simulationroom999.com/blog/diagnostic-communication-en-back-issue/

Introduction.
Simulation results
SingleFrame Explanation
FirstFrame Explanation
Conclusion

Introduction.

Check the CAN-FD simulation results in can-isotp.
This article will focus on SingleFrame and FirstFrame.
The explanation will be given while looking at the logs on the actual CAN-FD line.

Simulation results

The log on the CAN line after the simulation looks like this.
Long messages are omitted.

Begin Triggerblock
 0.000000 Start of measurement
 0.000000 1  18DA10F1x       Rx   d 8 07 01 02 03 04 05 06 07
 0.014868 1  18DAF110x       Rx   d 8 07 01 02 03 04 05 06 07
 0.203358 1  18DA10F1x       Rx   d 64 00 3C 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 55 55
 0.222282 1  18DAF110x       Rx   d 8 07 01 02 03 04 05 06 07
 0.404857 1  18DA10F1x       Rx   d 64 10 78 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02
 0.421732 1  18DAF110x       Rx   d 8 30 00 00 CC CC CC CC CC
 0.422724 1  18DA10F1x       Rx   d 64 21 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 55 55 55 55 55
 0.448758 1  18DAF110x       Rx   d 8 07 01 02 03 04 05 06 07
 0.609231 1  18DA10F1x       Rx   d 64 10 00 00 00 13 88 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08
 0.611156 1  18DAF110x       Rx   d 8 30 00 00 CC CC CC CC CC
 0.612213 1  18DA10F1x       Rx   d 64 21 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01

/*omission*/

03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09
 0.618979 1  18DA10F1x       Rx   d 64 2E 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02
 0.619053 1  18DA10F1x       Rx   d 32 2F 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 55 55 55
 0.651149 1  18DAF110x       Rx   d 8 07 01 02 03 04 05 06 07
End TriggerBlock

SingleFrame Explanation

SingleFrame of 7 bytes or less is the same as before.

 0.000000 1  18DA10F1x       Rx   d 8 07 01 02 03 04 05 06 07

And for SingleFrames of 8 bytes or more, the specification is that the first line is 0x00 and the next 0x3C = 60 [bytes] is Length, which is exactly what it is.

 0.203358 1  18DA10F1x       Rx   d 64 00 3C 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 55 55

FirstFrame Explanation

The conventional FirstFrame of 4095 bytes or less is the following nibble of the first byte and the second byte is Length.

 0.404857 1  18DA10F1x       Rx   d 64 10 78 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02

For FirstFrame exceeding 4096 bytes, the following nibble of the first byte and the second byte are 0x000, and the 4 bytes after that are Length.
In this case, 0x1388=5000[byte] corresponds to this.

 0.609231 1  18DA10F1x       Rx   d 64 10 00 00 00 13 88 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08 09 10 01 02 03 04 05 06 07 08

Now that we have confirmed that can-isotp is capable of CAN-FD diagnostic communication, the next step is to consider how to deal with AUTOSAR-DCM.

Conclusion

CAN line logged.
Checked SingleFrame.
- SingleFrame of 7 bytes or less.
- SingleFrame with more than 8 bytes.
FirstFrame check.
- FirstFrame of 4095 bytes or less.
- FirstFrame with 4096 bytes or more.

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