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SN65HVD265 / datarate, CAN_Tx frequency

Ryuji
Guru 20090 points
Other Parts Discussed in Thread: SN65HVD265

Hello,

Please let me know about SN65HVD265.

(1)
Could you please let me know the TXD freaquency for 2Mbps datarate?
Is this over the 16MHz?

(2)
If yes, could you please let me know the reason of difference between CAN-FD datarate and TXD?

(3)
Could you please let me know the CAN Output waveform when we input the 16MHz by Signal Generator?
Are there any output waveform without protcol?


Best Regards,
Ryuji Asaka
Ryuji 

  • 0
    TI__Prodigy 740 points

    Hi Ryuji,

    thanks for your questions.

    (1)

    If you consider a signal generator with a square wave output signal connected to the TXD pin of our transceiver, the generator output frequency would be 1MHz for a transmitted data rate of 2Mbps.

    The frequency given by the signal generator describes a full period consisting of a high and a low state. The transceiver will take this high state as one bit ("1") and the low state as a second bit ("0"). So the data rates equals the frequency of the square wave times two. 

    (2)

    In a real application your TXD signal is data too. If you have a data rate of 2Mbps for the TXD signal it will be the same on the bus. 

    In CAN-FD you are able to transmit with two different data rates within a single frame. A CAN-frame consists of different fields like the control field, the arbitration field, ... and the actual data field. The actual data bits can be transmitted with a higher data rate (for our devices spec. up to 2Mbps), while the "rest" will still be transmitted with max. 1Mbps.

    (3)

    Since our devices are only specified to work up to 2Mbps and a 16MHz squarewave TXD signal would equal 32Mbps those output waveforms are not specified.  

    The transceiver does not take care of the CAN protocol, that has to be ensured by software.

    If you have any further questions, I will be glad to help you.

    Best regards,

    Chris

  • 0 in reply to Christian Klickow
    Guru 20090 points
    Hello Chris san,

    Thank you for the reply.
    And sorry for my misunderstanding about data rate.
    I have additional question.

    Could you please let me know the device difference between CAN-FD and CAN transceiver?
    I think that there are any updating in the CAN-FD device for achive the high data rate.
    Please let me know the overview of that updating if you can.

    Best Regards,
    Ryuji Asaka
  • 0 in reply to Ryuji
    TI__Prodigy 740 points

    Hello Asaka san,

    the difference between our CAN-FD and CAN transceivers lies in the specified and characterized data rate.

    The technical details are TI IP and must not be shared externally. I am sorry that I can't give you a more detailed explanation.

    Best regards,
    Chris