AM2432: MCAN FD external counter

Tool/software:

We also use MCAN FD on AM2432 (same as  AM6442) with external counter enabled.

We are wondering which is the clock source (ICLK) driving the counter because we would like to measure the time difference between:

- actuial time:

       we take a sample of external counter with MCAN_getTSCounterVal(gMcanBaseAddr)

- incoming rx message timestamp:

     MCAN_RxBufElement rxMsg;

     MCAN_readMsgRam(gMcanBaseAddr, MCAN_MEM_TYPE_BUF, 0U, 0, &rxMsg);

     rxMsg.rxts;

Are the result of MCAN_getTSCounterVal and rxMsg.rxts comparable ? 

Should we use a conversion formula to adapt the result of MCAN_getTSCounterVal to rxMsg.rxts ?

Thank you in advance.

    Andrea