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SN65HVD1050: sn65hvd1050

jose manuel perez
Prodigy 10 points
Part Number: SN65HVD1050

Hi,

I observe that sometimes in the end of frame a high bit is present and I think the frame is not valid.

Other tmies this hig bit is preent in  the acknolege bit, but hte frame is valid.

Someone could me tell me what is happends?

The system are three borads connected whit CAN bus by means of SN65HVD1050. The distance between boards are 10 cm.

is a valid frame

Invalid frame

I don't understand why this overvoltage is in the middel of the end of frame.

Thank you

  • 0
    Guru 286090 points

    The ACK bit at the end of the frame is driven by all devices that have received the frame. The combined outputs of multiple devices have a higher drive strength, so the differential voltage will be higher. This is normal, and does not make the frame invalid.

  • 0 in reply to Clemens Ladisch
    Prodigy 10 points

    and the high bit in the middel of the end of  frame? why happens? any idea?

  • 0 in reply to jose manuel perez
    Guru 286090 points

    This is the ACK bit. The two receiving devices both decided that they have received the frame, so it appears that this frame is valid.

    In any case, the SN65HVD1050 works on the electrical level; its outputs correspond directly with the signal at its TXD input. If you think that the frame is invalid, you have to look at your CAN controller.

  • 0
    TI__Mastermind 26736 points

    Jose,

    If an error occurs during communication, nodes on the bus indicate an active error by transmitting 6 consecutive dominant bits on the bus. If there were an issue in communication, you would likely see something resembling 6 consecutive zeros. Here, this is not the case. It seems to be valid communication as Clemens noted.

    Extra bits in the EOF field would constitute an error condition and your controller would detect this.

    Best,

    Danny