### AUTOSAR and Time Synchronization over CAN

If you are checking documentation from AUTOSAR about time synchronization over CAN you can get a bit confused by looking at figure 1. Here I’ll try to clear it out with some examples.

Figure 1 - CAN Time Synchronization mechanism

If you put numbers inside equations you will get something like the result in figure 2. The result is 4.100 [s] but by looking at the graph you will expect to get 5.100 [s]. That is because this sync method doesn’t include compensation for transfer (latency) delay. Engineers who developed this method consider CAN communication delay is negligible, but they didn’t draw a sequence diagram that way.

Figure 2 - calculation example with delay problem

To make things more understandable let's draw a graph without communication delay.

Figure 3 - calculation example with no delay problem

Does this have more sense now?

Thank you for the clarification.

ReplyDeleteI had the same concern regarding this specs.

Thank you for leaving a comment. I am glad this was useful.

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