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TCAN1145-Q1: Do we need to write any initial SPI command to let TCAN1145 work?

Gibbs Shih
Expert 5255 points
Part Number: TCAN1145-Q1
Other Parts Discussed in Thread: TCAN1145EVM

Hi, Dear Expert,

As title description, schematic review is same as below link.

https://e2e.ti.com/support/interface-group/interface---internal/f/interface---internal-forum/1245369/tcan1145-q1-tcan1145dmtrq1?tisearch=e2e-sitesearch&keymatch=TCAN1145DMTRQ1#

If VCC/VIO/VSUP power is fine, Can TCAN1145 direct works without SPI initial command?

Because we do not measure +2.5v on CANH/CANL, so I am not sure SPI initial command is necessary or not?

Need your suggestion.

Many Thanks

Gibbs

  • +1
    TI__Guru 53555 points

    Hi Gibbs,

    When power is initially supplied to the TCAN1145, it will start up into Standby mode. While in Standby mode, the bus biasing may be disabled to conserve power. A SPI write to the mode control register is needed to place the device into Normal mode for the CAN bus to become active. Normal mode will ensure that the CAN bus bias (2.5V) is active and will allow the transceiver to drive dominant when the TXD pin is driven low. 

    If you are using a TCAN1145EVM, there is a microcontroller build-in that can generate these SPI messages with the help of the TCAN1145 GUI:
    https://dev.ti.com/gallery/view/TCAN114x/TCAN114x/ver/1.0.0/ 

    Let me know if you have any more questions.

    Regards,
    Eric Schott