• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 34 subscribers
  • Views 354 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

TCAN1043-Q1: Is there any way to confirm that the data sent by the TXD RXD of the TCAN1043 to the SOC is OK?

TCAN1043-Q1: Multi Master Question

Mike Yu
Intellectual 2750 points

Part Number: TCAN1043-Q1
Other Parts Discussed in Thread: TCAN1043

Hi Team,

The customer is working on the schematic, could you please kindly help to answer the question below? Thank you.

1. If the two CANs are connected together, but the two CAN signals come from different MCUs, is this feasible? Did our CAN device have the mechanism of Multi-Master operation?

2. If the VCC and VCCIO of CAN1 and the VCC and VCCIO of CAN2 are connected to different domains, will there be a problem of voltage recharge?

Best regards,

Mike

  • 0
    TI__Guru 53535 points

    Hi Mike,

    1. The CAN interface is designed to be used in a multi-commander (or "multi-master") configuration as no single node has inherent priority or control over the bus. The CAN protocol includes an arbitration phase in the CAN frame that is used to determine which node has priority on the bus for the upcoming message, allowing any node to act as the system commander when it has the highest priority message. From the physical layer, the transceiver itself facilitates this with the drive states (recessive and dominant) defined by the CAN standard - so there is no additional consideration for the transceiver when using them in a multi-commander system. 

    2. Because the CAN bus communicates using a differential signal between the CANH and CANL line, the common mode (or common ground) ideally has no impact on the signal itself. This allows nodes sharing the CAN bus to operate over longer distances with potential ground shifts and power domains. The limit to this will apply when the common mode exceeds the transceivers' common-mode range (+-12V typically, +-30V for TCAN1043). So a potential ground shift greater than this common mode range may introduce issues, but otherwise different power domains will be no issue here. 

    Also keep in mind that Vio only determines the IO voltage used by the digital pins interfacing with the local MCU. This does not directly impact any output voltage or input threshold on the CAN bus-side of the device. 

    Let me know if you have any more questions.

    Regards,
    Eric Schott

  • 0 in reply to Eric Schott1
    TI__Intellectual 2750 points

    Hi Eric,

    Thanks for your reply, it is clear with me.

    Best regards,

    Mike