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PCF8575： PCF8575 interrupt problem

Luo XiuFeng
Intellectual 676 points
Part Number: PCF8575

I want to know what triggered the interruption of PCF8575. For example, I use PCA9545 to link PCF8575, and I have opened the 16-channel IO port of PCF8575. How does PCF8575 pull down the interrupt pin to notify PCF8575? How does this process work? How do I configure it?

  • 0
    TI__Mastermind 49130 points

    Hello user5170101,

    PCF8575 should be set to an output HIGH inorder (if set to output low, the strong pull down will fight with any outputs pulling high) to weakly bias the line high and allow for external drivers to pull low or high.

    The INT will trigger when the pin changes state and will reset when the pin goes back to the original state or if a read occurs on the port that caused the INT.

    The device does not have any registers, you should just do a write and set the pins that you want to be an input to an output HIGH.

    -Bobby