title: How would an ISR know what pin cause the interrupt?
body: <p>Interrupts can be enabled for a specific pin(s) on a digital I/O port, correct? How would the ISR determine which pin caused the interrupt?</p>
  
  <p>Because the vector table has only one slot for the Port1 ISR. So the same ISR function gets called no matter which input pin on Port1 needs attention unless I'm wrong...</p>