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TMS320F28377S: CAN interface - Without transceivers

sivasuryan.R
Intellectual 610 points

Part Number: TMS320F28377S
Other Parts Discussed in Thread: AM5728

Hi

   Is that possible to connect the TMS320F28377S controller with AM5728 processor using CAN interface but without CAN Transceivers. I have only two nodes (AM5728 and F28377S) in the same board.  I had seen some application notes showing CAN interface connection without transceivers as in below links. Kindly provide me the confirmation.

Links:

http://www.mikrocontroller.net/attachment/28831/siemens_AP2921.pdf

https://www.renesas.com/en-eu/doc/products/mpumcu/apn/rl78/001/r01an2535ed0200_can.pdf

Thanks and regards,

R.Sivasuryan

  • 0
    Guru 192875 points
    Hi Sivasuryan,

    CAN Transceivers are very much recommended. I'm not sure of CAN functionality without them and I would highly doubt its reliability.

    Regards,
    Gautam
  • 0 in reply to Gautam Iyer
    TI__Mastermind 42310 points

    Hi Sivasuryan,

    For connecting 2 nodes in the same PCB, the diode and the pull up resistor technique that you showed in the links is one way that you can establish a link without the use of transceivers.  This method only works for short distances (like in your case where you have both nodes in the same PCB) and as Gautam pointed out this may not be reliable.

    Another option you can try is to connect both nodes together with an AND gate as shown below:

    Again, both options are for use only in very short distances.  CAN transmission has to have a way to monitor/ACKnowledge that what is transmitted is monitored back.  In both schemes (diode/pull up resistor or the AND gate implementation), the RX lines is where the ACKnowledge of the transmitted signal is carried out.  These are just suggestions that you can try.  We strongly recommend that you thoroughly check that your application works on all conditions if you decide to implement either of these suggestions if you are to eliminate the use of transceivers.

    Best regards,

    Joseph  

  • 0 in reply to Joseph Casuga
    TI__Mastermind 42310 points
    Hi Sivasuryan,

    I have not heard from you after my post so I am assuming that you have resolved your issue.

    Regards,
    Joseph