digitalRead() speed on analog vs digital pins

Just curious about this...

I know on Arduino that one can use certain analog pins as digital pins.

Is digitalRead() on a digital pin faster/slower/same speed as digitalRead() on an analog pin used as digital pin?

For example, on a Nano:
digitalRead(4) [digital pin 4]
digitalRead(14) [analog pin A0]

AFAIK the performance is identical. have you any reason to think it is not?

By the way digitalRead(A0); is also valid.


"have you any reason to think it is not?"

Hi Robin - no, not at all. It was a purely theoretical question.

They both use the same kind of registers and use the same digital input and output circuit.
The analog input circuit is connected to the same pin as the digital circuit. You can use both at the same time if you want.