Use of shared interrupt pins

I see from the documentation that certain pins share the same interrupt handler. For example on the Electron, I believe A1 and D4 share the same handler (among others).

Does this mean that if I use A1 as an interrupt line, that I can’t use D4 for other I/O purposes (because activity on D4 would trigger A1’s interrupt)? Or is it just that I can’t attach another interrupt to D4?


You can A1 and D4 for both for GPIO, but you can only use attachInterrupt on one. So if you attachInterrupt(A1, …) you can still use D4 for GPIO, just not attachInterrupt to it.