Hello fernando.barrios@uwaterloo.ca, dumitru-daniel.popa,
Sorry for the delayed answer on this topic, I missed it; I think it was answered here . To answer the question, here is the output of the CAN block:

This timestamp is part of the MB structure (2B long), and is a value that the free running timer returns.

The TIMER_SRC bit (from CAN_CTRL2) is negated, thus the free running timer is clocked by the CAN bit-clock (the one that defines the baud rate on the CAN bus). This timer increments by one after each bit (received/transmitted); when there is no message on the bus, it counts using the programmed baud rate.
You can find out more details in the reference manual, in FlexCAN -> Functional description -> CAN protocol related features -> Timestamp.
Kind regards,
Razvan.