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TCAN4550-Q1: suggestions for when to reset TCAN4550?

Yuan Tan63
Expert 3280 points
Part Number: TCAN4550-Q1
Other Parts Discussed in Thread: TCAN4550

Hi,

Customer want to know when to recover TCAN4550? what indicator we can get from registers?

recover means: reset pull high for 30us then pull low

thank you!

B&R

Yuan

  • 0
    TI__Guru 53555 points

    Hi Yuan,

    There is no requirement to reset the TCAN4550 for any particular interrupt case. The reset is a tool that the software designer can use to place the IC into a known memory state if this becomes unknown for any reason. For example if the MCU power cycles or needs to reset for any reason, it may choose to reset and reconfigure TCAN4550. This will prevent a scenario where an unknown state is maintained if the MCU reset occurred during a SPI transaction to TCAN4550 for example. 

    Let me know if you have any more questions. 

    Regards,
    Eric Schott 

  • 0 in reply to Eric Schott1
    TI__Expert 3280 points

    hi Eric, 

    thank you! and customer want to check if their "recovery" process for TCAN4550 is reasonable or have risks:

    1)reset pull high 30us then pull down

    2)delay for 700us

    3)judge for 3 times, if current status is standby

    4)enable interrupt, read interrupt flag, enable protection, config CCCR, set global filter, set CAN bit timing 5, clear up all MRAM

    5)set MRAM CFG

    6)write SID filter in MRAM

    7)close up protection, enable MCAN interrupt, set in normal mode

    8)clear up all interrupt

    besides that, for criteria to start the TCAN4550 "recovery" process:

    1) check MCAN-TXBC, if not correct, start "recovery" process

    2) check REG_MRAM, if not correct, start "recovery" process

    3) when application layer request for sleep and TCAN4550 in sleep mode, if test application layer request for normal communication, start "recovery" process

    4)when TCAN4550 in standby status, if notice the IR_PWRON，IR_UVSUP（Power failed）or IR_UVIO（VIO under voltage）,  start "recovery" process

    thank you!

    B&R

    Yuan Tan

  • 0 in reply to Yuan Tan63
    TI__Guru 53555 points

    Hi Yuan,

    Sorry for the delay here.

    This sequence and recovery sources look good to me. All the timings are valid and the order of operations are correct for propper reset and configuration of TCAN4550.

    Regards,
    Eric Schott