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TIC12400-Q1: The switch status of the 12400 chip collection cannot change with it

ian wu
Intellectual 425 points
Part Number: TIC12400-Q1
Other Parts Discussed in Thread: TIC12400

Hello experts

We used TI's TIC12400 chip. After it was loaded and used for a period of time, a fault occurred. The switch status collected by the 12400 chip could not follow the change.

With the debugger, all the switches collected by the TIC12400 chip are 0 (that is, all the values given to the upper layer are 1 after inverting).

After the debugger is installed, the ID of device 12400 read is 0, and all values in the status register are 0. According to the driver design logic, ECU running process, if the chip failure, will lead to periodic reset. -- After several tests, it is found that the chip is reset "repeatedly", and each reset fails (that is, the chip driver initialization is unsuccessful).

Attached is the schematic diagram.

TIC12400原理图.pdf

  • 0
    TI__Mastermind 19360 points

    Hi Ian,

    Can you elaborate more on what type of fault occurred?

    When you say that the chip is reset "repeatedly" are you saying that the Reset Pin is getting pulled high repeatedly, or the microcontroller is trying to issue a software reset through SPI?  Can you elaborate what you mean by this reset "repeatedly" statement?

    Have you monitored the voltage rails?  Are the VS and VDD power rails at the correct voltage and expected current levels?  If the VS power drops below the undervoltage power on reset (POR) threshold, the device will be reset.  If VDD is not at the correct level, it can prevent SPI communication.

    Is the device temperature at a normal level?  If the "fault" you reported damaged the device or some portion of the circuit, this could cause increased current draw and create a thermal issue.  If the temperature increases to an unsafe level, the device could have a thermal shutdown.  Is the device hot or drawing excessive current?

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    Intellectual 425 points

    hi  Jonathan

    the Reset Pin is getting pulled high repeatedly. Could you please check the schematic to see if there is any problem?

  • 0 in reply to ian wu
    TI__Mastermind 19360 points

    Hi Ian,

    The Reset pin is an Input Pin with an internal 1M pulldown resistor.  The schematic only shows an additional 100k pulldown resistor on the Reset pin which would hold the line low for normal operation.  I assume this pin is connected to a GPIO pin of the MCU, but this is not shown in the portion of the schematic you have shared.  It only shows an off-page net reference "PF8."  If the Reset pin is getting pulled high, then the MCU or other circuit connected to the PF8 net is causing this to happen. 

    Assuming this is connected to an MCU, I would suggest reviewing the MCU code for when and why it would pull the Reset Pin High.  I suspect that it might perform this function at the beginning of an initialization routine to ensure the device registers start off with their default values.  There may be other reasons it would try to re-initialize the device such as in case of a detected fault or under-voltage condition as you have alluded to.

    Regards,

    Jonathan