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TMDSDOCK28379D: CAN transceiver issue

Kash Olia
Genius 3215 points
Part Number: TMDSDOCK28379D
Other Parts Discussed in Thread: LAUNCHXL-F28379D, SN65HVD257, RS485-FL-DPLX-EVM

Hi,

I'm using controlCARD TMDSDOCK28379D but just realized that the kit doesn't have CAN transceiver module so I can't read the differential CAN_H and CAN_L signals, however I can read CAN_TX and CAN_RX at the MCU side which are not differential. In addition, I realized that LAUNCHXLF28379D has the CAN transceiver so CAN_H and CAN_L signals are available to communicate over CAN bus. So:

1. why the CAN_RX and CAN_TX are available on the MCU but there is no CAN transceiver installed on the board? 

2. Is there any CAN transceiver module that I can buy individually and connect it to my controlCARD?

Regards,

Kash

  • 0 in reply to Hareesh Janakiraman
    Genius 3215 points
    Hareesh,
    Thanks for your reply.
    Don't you think switching to "LAUNCHXL-F28379D" ($33.79) would be cheaper? I guess "LAUNCHXL-F28379D" uses "SN65HVD234D" CAN transceiver, please correct me if I'm wrong.

    Kash
  • 0 in reply to Kash Olia
    Guru 192875 points

    Khashayar olia said:
    Don't you think switching to "LAUNCHXL-F28379D" ($33.79) would be cheaper?

    That's your call but remember that on launchpad you would be able to use only one CAN module ie CANB.To use the other one ie CANA you'll have to again use an external transceiver.

    Khashayar olia said:
    I guess "LAUNCHXL-F28379D" uses "SN65HVD234D" CAN transceiver, please correct me if I'm wrong.

    Yes you're right!

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    TI__Guru 57255 points

    Hi Kash,

    We decided not to put a CAN transceiver on the controlCARD itself to enable customers to utilize the full pinmux and not make assumptions on how customers would like to experiment with our device.  Doing so also enables TI to make more application baseboards which are able to show off more of our C2000 device.  Note that we also didn't add I2C EEPROMs, FET drivers, RS485 transceivers for SPI, etc.

    The LaunchPad makes more assumptions on how you want to evaluate our device.

    ===

    Both paths you are considering are feasible.


    Thank you,
    Brett

  • 0 in reply to Brett Larimore
    Genius 3215 points

    Brett,
    Thanks for your reply. It totally makes sense, it actually opens developer's hands to do more with your devices.

    How do I find out what transceivers are installed on the board? I couldn't find it in datasheet.

  • 0 in reply to Gautam Iyer
    Genius 3215 points

    Gautam,
    Thanks for verification. Since TMDSDOCK28379D doesn't come with RS485 tranceiver, it seems I need to purchase this extra component as well. Have you had experience working with CAN and Serial transceivers? if so, do you suggest any device?

    Does LAUNCHXL have RS232, RS485/422 transceivers?

    Regards,
    Kash

  • 0 in reply to Kash Olia
    Guru 192875 points

    Khashayar olia said:
    Have you had experience working with CAN and Serial transceivers? if so, do you suggest any device?

    As for CAN transceiver you can go for the same part number as in Launchpad.

    Khashayar olia said:
    Does LAUNCHXL have RS232, RS485/422 transceivers?

    Nope you'll have to use an external one. But I hope that you know the kit has a USB to Serial Converter wherein you can observe data transfer of one of the SCI module on PC through an assigned COM port.

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Genius 3215 points

    For CAN transceivers,

    I found three CAN transceivers EVM: TCAN10XX, SN65HDV255 and SN65HVD257 where the later EVM comes with two SN65HVD257 which is suitable for set up in a redundant configuration. The one that's used in LAUNCHPAD is SN65HVD234D which I couldn't found the EVM for it. Since they are all compatible with ISO 11898-2 high speed CAN standard, I assume I can use any of those. Please correct me if I'm wrong.

    For serial 485/422 transceivers,

    Yes, I found this part of the schematic and also watched your youtube about SCI:

    But I didn't find anything on TMDSDOCK28379D schematic about serial transceivers. do you know any serial EVM or have you worked with one of them so far?

    Thanks,

    Kash

  • 0 in reply to Kash Olia
    Guru 192875 points

    Khashayar olia said:
    But I didn't find anything on TMDSDOCK28379D schematic about serial transceivers. do you know any serial EVM or have you worked with one of them so far?

    For serial, there's no evm as such but you can simply use the part. Explore the same here:

    Also, don't forget to choose a 3.3v part.

    Regards,

    Gautam

  • 0 in reply to Gautam Iyer
    Genius 3215 points
    Gautam,

    I found a serial tranceiver EVM and just ordered it:
    RS485-FL-DPLX-EVM
    www.ti.com/.../rs485-fl-dplx-evm

    I will post my experience working with it soon. thanks.
  • 0 in reply to Kash Olia
    Guru 192875 points
    Cool. Do keep us informed!

    Goodluck & Regards,
    Gautam