I ran into some trouble recently trying to connect a TI LMT01 temperature sensor to the internal comparator of the UNO R3 ATmega328p. Even with the ACSR properly set up, the sensor would simply not trigger the interrupt from the sensor’s falling edges. While researching the issue, I found this page which suggested connecting the sensor outputs to D7 instead of A1 like i originally did, which solved the issue.
My question is, why D7 instead of A1? Referring to the image attached, the ACSR controls only inputs between A1 and A0 (Of which A0 is connected to the reference voltage), how does D7 factor into this? And why will A1 not work?