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TCAN1146-Q1: Configuration command

Fabio Gou
Expert 4435 points
Part Number: TCAN1146-Q1

Tool/software:

1. Could you help to explain the configuration command?

Do read and write commands send two bytes of data in the configuration command? How do we combine the hardware address and the command word? Just send it out?

2. Is there a problem with configuring the following command words?

such as reading the current mode configuration of the transceiver, sending [0x10<<1, 0x00], configuring the current mode of the transceiver to normal mode, sending [(0x10<<1) | 0x01, 0x07];

3. Does the MCU need to prioritize configuring the initial working mode after the transceiver is powered on?

  • 0
    TI__Guru 53555 points

    Hi Fabio,

    Fabio Gou said:
    1. Could you help to explain the configuration command?

    It looks like your understanding here is correct. The configuration command above for a read first constructs the first byte using the 7-bit address shifted left and the read/write bit (0 for read so left as-is). The data in the second byte is irrelevant, so 0x00 is sent in order to generate the signal on SCLK for the transceiver to respond with the read data. In the figure below, the flag line on SDI after R/W is this 0x00 being sent by the controller and is ignored by the transceiver. 

    Fabio Gou said:
    2. Is there a problem with configuring the following command words?

    Sending the bytes [(0x10 << 1) | 0x01, 0x07] is correct for a write command (ORing with 0x01) to the mode control register (address 0x10) to set the device to Normal mode (111b = Normal).

    Fabio Gou said:
    3. Does the MCU need to prioritize configuring the initial working mode after the transceiver is powered on?

    This will depend on the priorities of the system. If the system needs to establish communication with the CAN bus as a priority, then yes the MCU should initially change the mode of the transceiver into Normal mode. If there is some other priority task such as initiating a local power supply for other modules, then this can be done first. The transceiver will remain in Standby mode after a wake event for around 4 minutes (tINACTIVE) before automatically switching back into a low power Sleep state. 

    Let me know if you have any more questions.

    Regards,
    Eric Schott