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PCF8575C: Pulse signal recognition

Part Number: PCF8575C
Other Parts Discussed in Thread: BQ25601, PCF8575, SN74LVC2G74, TCA8418

Hi Ti Team

I plan to use several 'BQ25601(4EA~)' by connecting them to the MCU.
MCU needs to read the INT signal of BQ25601 through PCF8575,
Can MCU recognize pulse signal through PCF8575?



  • The PCF will activate its interrupt output when any input pin changes, but it will deactive the interrupt when the input changes back. So you can recognize the signal only when you read the input port of the PCF quickly enough.

    If you cannot guarantee that you have completed the read inside of 256 µs, then you have to store the interrupt state in a flip-flop (e.g., SN74LVC2G74) and to clear it manually.

  • Hi Jeong,

    Just to add onto what Clemens said, we don't have any I/O expanders currently that latch the INT pin when an input port changes value. The TCA8418 does but it is more of a keypad scanner.