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How to time-stamp DCAN Receive Messages

Pashan None
Genius 5660 points


Hello Support,

For the ARM7TDMI Device with HECC [ spnu197e.pdf ], there were the following items :

"Object Time Stamp Registers (MOTS)"

as well as

"The message object time-out registers (MOTO) are implemented as a RAM."

Can you please how to perform Receive Message Time-Stamp as well as  Time-Out with DCAN?

Thank you.
Regards
Pashan

  • 0
    Mastermind 7585 points

    As far as I know there is no MOTS or MOTO - functionality in the Hercules - DCAN, but I am sure you wlll get the right answer from the Support Team.

     

     

  • 0 in reply to Frank Bormann
    TI__Guru 68980 points

    Frank,

    Thanks for the quick answer.  I agree.

    What could be done I think is in a little more gross a fashion.  The VIM has the ability to route any two peripheral interrupt requests to the RTI counter's capture units. 

     

    Since the CAN module generates interrupt requests, you could time it's interrupt requests.   This probably isn't as selective as what HECC has but maybe it's sufficient.

    EDIT:  I thought I should add - the architecture of the RTI is such that the free running counter, which is used for all capture and compare units, is not reset during normal operation (i.e. at the end of the compare period like on some timers).  Instead the compare period is held in a register and when a compare match occurs the compare register is updated to current compare val + compare period.    

    What this means is you can use the capture feature of the RTI independently of the RTI compare periods.  So no worry about conflicts between your OS tick and using the capture units for timestamping like this. 

  • 0 in reply to Anthony F. Seely
    Mastermind 7585 points

    Anthony,

    I agree that RTI caould be used as a sort of a timestamp-function. However, It will not be sufficient as a replacement for the HECC - functionality. In HECC the timestamp function is based on the physical time on the CAN - communcication, it stamps the time, when a mailbox has actually been transmitted or the time, when a message has been physically received.

    To use the Hercules - DCAN option of forcing the CAN-IRQ to trigger the RTI is not the same. For example, if you have some other IRQ running and  in the meantime 3 new messages received in 3 different mailboxes and the , you cannot separate the 3 different timestamps. Furthermore, the option to set timeout - periods for CAN - messages is not possible with DCAN. And the CAN  time synchronisation with LNT is also only present with the HECC.  So for a TTCAN - style application the HECC has advantages over the DCAN.

    Regards, Frank

     

     

     

  • 0 in reply to Frank Bormann
    TI__Guru 68980 points

    Thanks Frank.
    I agree it's not the same.  But its' about the closest you can get w. DCAN.  I can't think of another option.