I want to connect 5 of pcf8574t on my AVR ATMEGA32L. One for LCD 2x16 and 4 for general purpose I/O. The question is: if i get an interrupt signal from one of 4 chips, how can i know which chip has send the interrupt?
I think that circuit may be usefull to apart interrupt signal.
This circuit x4 times (one from each PCF8574T chip). "mcu Interrupt pin" connected together to AVR Global Interrupt pin, such as INT0, or INT1. "PINx mcu" pin, connected seperate to a GPIO pin of AVR such as PB7, PB6, PB5, PB4. and "PCF INT OpenDrain" connected also seperate to INT pin of PCF8574T.
but i don't know if this circuit it's working 100% .