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Original question:

TCA6416A -About I2C spike time

TCA6416A: Interrupt output

Shunsuke Nagata
Genius 12240 points
Part Number: TCA6416A

Hi, team,

Could you please let me know about INT feature?

1. Is there two type of use case for INT? One is a interrupt signal when data on the port is changed (input mode?) And another is signal for the indicator which is Ack / NACK on I2C ( Read mode?) Is my understanding correct?

2. If my understanding of 1 is correct, how can user select each mode?

3. If my understanding of 1 is correct, could you please let me know the INT timing chart for input mode.

4. Data sheet shows " when data on the port is changed to original setting or ..." as below. What is original setting?

Regards,
Nagata.

  • 0
    TI__Guru 62910 points

    Hello Nagata-san,

    The INT output is only used to indicate a change in the state of an IO from its previously-read ("original") value. When an interrupt is asserted, it is cleared by reading the input port values. Specifically, the deassertion of the INT output would occur on the ACK or NACK bit of the read transaction. Is this explanation clearer? Please let me know what further questions you have.

    Regards,

    Max

  • 0 in reply to Max Robertson
    TI__Genius 12240 points

    Hi, Max,

    Could you please let me know if my understanding is correct?

    If IO state is changed, Read timing include INT become the timing of Figure 32.

    But if IO state is not changed, the INT signal is not set. (INT signal keep to be during reading)

    Is the understanding correct?

    Regards,

    Nagata.

  • 0 in reply to Shunsuke Nagata
    TI__Mastermind 49270 points

    Hey Nagata,

    The INT remains High (deasserted) when the the IO state has not changed.

    INT will flip to LOW (asserted) when IO state changes.

    INT will flip back to HIGH (deasserted) if the IO state changes back to its original state before a read ACK has occurred.

    The original state above is the state after PoR or after a read ACK has occurred.

    This means if the INT is flipped LOW (asserted) because the IO state changed and then a read ACK occured, the new original state is the state that asserted the INT, then the INT is deasserted.

    -Bobby