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TCAN4550: CAN Bus no output

Yishan Chen
Intellectual 1670 points
Part Number: TCAN4550

Hi,

My customer used M3+TCAN4550 with CAN 2.0B Debug tool and a Host to achieve SPI to CAN.

Now they have met the question that they can't see any output in TCAN4550. I have asked several question to locate the problems and I will summarized below.

First ,they used the write command in the TCAN4550 demo:

And the status register is 0x0830,which means these bits are wrong:

And the MISO/MOSI/nCS/CLK waveform(the Ringing is up to 5.8V),Yellow one for CLK, Green one for MOSI, Blue one for nCS, Pink one for MISO:

Please help us to debug, thank you very much.

Best Regards,

Yishan Chen

  • 0
    TI__Mastermind 33050 points

    Hi Yishan,

    The failure to send a CAN message are likely due to the errors in the SPI communication.  There does appear to be a lot of noise, and this could lead to errors.  But there could also be some larger protocol errors.  Can you share some scope plots that show a complete SPI Read/Write?  I would like to see all of the clock and data bits between the nCS pin transitioning Low at the beginning of the transaction, and then high again at the end of the transaction.  This will help me see if there is some sort of protocol change needed in the SPI drivers.

    Regards,

    Jonathan