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IWR1642BOOST: CAN bus MUX problem

XINJUN DONG
Intellectual 300 points
Part Number: IWR1642BOOST

Hi there,

I am recently working with CAN bus on IWR1642BOOST (V2). I am trying to read signal from RX pin after the CAN transceiver (TCAN1042HGVDQ1) but get nothing when running the CAN driver test coming with SDK. I have made sure that the position of S2 is on "CAN" side. Later, I tried to test the connection and found that the MISO1 and MOSI1 pins are directly connected with Pin 14 and Pin 12 on J5 which is different from Table 1 on Page 7 of the 1642BOOST user guide. Now, it seems impossible to read RX message from CAN transceiver from J6 or J5 connector. I would like to ask whether it is a design mistake. If so, would it be possible to be fixed in the next version?

Thanks, 

Xinjun

  • 0
    TI__Mastermind 24955 points
    Xinjun,

    Did you make sure to complete the following? These steps are working under the assumption that you have a Rev B board.

    NOTE: For CAN use, a modification is needed along with the S2 position:
    • Remove R11
    • Connect U3-1 to U14-12 CAN_Tx
    • Remove R12
    • Connect U3-4 to U14-9 CAN_Rx

    This comes from section 2.3.3 "CAN Interface Controller" in the IWR1642BOOST User's Guide that can be found here: www.ti.com/.../swru521b.pdf

    Please keep in mind that you lose SPI functionality when you change to using the CAN bus.

    Regards,
    Kyle
  • 0 in reply to Kyle Cousino
    Intellectual 300 points

    Kyle,

    Thank you for the reply. I tried to look into it, and it can solve the problem. However, I have to say soldering around U14 is really difficult and can easily damage the board. For now, my solution is to keep the SW2 at "SPI", and get the CAN TX and RX signal from SPICLK1 and CS1 on J6 and J5 respectively. Afterwards, I am going to use an additional CAN transceiver to transfer the CAN bus signal. Please help me verify that the solution will work. 

    I would like to confirm one whether the CAN_TX and CAN_RX is mux with SPI_CLK1 and CS1 respectively or not. 


    To be honest, I still doubt that it is a design mistake by connecting CAN_TX to NC1 and CAN_RX to NC2, which make the CAN bus implementation almost impossible. It would be great that the design can be changed in the next version if there will be one.

    Thanks again for the help!

    Xinjun

  • 0 in reply to XINJUN DONG
    TI__Mastermind 24955 points
    Xinjun,

    On the IWR1642BOOST, the CAN_TX and CAN_RX lines are muxed with the two SPI lines. This aligns with my previous statement that you will lose SPI functionality when you change to using the CAN bus.

    Regards,
    Kyle