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TIC12400-Q1: 2 question about TIC12400-Q1

Hale Tan
Expert 3770 points
Part Number: TIC12400-Q1


Hi team,

I have some question about TIC12400-Q1.

It is assumed that one of the input signals is the wake-up source, and then successfully wakes up the MCU through INT. At this time, the MCU has woken up. Can I read which input signal wakes up through SPI?

Another question is, this is a 10-bit ADC acquisition, can the analog input be used as a wake-up source? For example, set a threshold, after exceeding this threshold, trigger the INT output, and then wake up the MCU

  • 0
    TI__Mastermind 34250 points

    Hi Hale,

    The SSC bit (bit 3) of the Interrupt Status register (INT_STAT) will be set when an input signal has changed states.  This will cause the INT pin to toggle and wake up the MCU.

    The MCU can then read the the value of the input signals as determined by the most recent polling cycle.  If the input signal that caused the wake up event is still in the state that woke up the MCU, then the MCU will be able to determine that this input signal is not at the expected default value and therefore it was the reason for the wake up.  However, if the input signal has already changed back to the other default state, then the MCU may not be able to detect which input signal was responsible for the wake up.

    Unfortunately there are no latched registers that will hold this information indefinitely, therefore it all depends on how fast the MCU can wake up and read the registers, and how long the input signals hold the state value before changing back to the previous state.

    Yes, the ADC can be used to generate a wake up because it can cause an interrupt to be generated on the INT pin just like with the comparator.  You would simply need to configure the ADC thresholds for your desired levels on the input pins and then enable the corresponding interrupt generation control bits in the INT_EN_CFG1 through INT_ENCFG4 registers.

    Regards,

    Jonathan

  • 0 in reply to Jonathan Nerger
    TI__Expert 3770 points

    Jonathan,

    Thanks!

    And do we have any devices can cache information about which input signal wakes up the mcu?

  • 0 in reply to Hale Tan
    TI__Mastermind 34250 points

    Hi hale,

    Currently we do not have a device that will cache or latch this status and the device always represents the pin state value from the most recent polling cycle.

    The polling cycle time can be adjusted between 2ms and 4096ms.  In theory, this could be used to allow the MCU enough time to wake up from sleep and read the registers before a new polling cycle begins and potentially overwrites the previous value.  This would just require some analysis on how long it takes the MCU to wake up and read the SPI registers.

    Regards,

    Jonathan