Declaring analog pins as digital and setting up with a loop

[sterretje]

@kousenshu

The grove connector is the one marked I2C Interface, so I assume SCL and SDA are the ones used? And the documentation does not mention (or at least I did not find that it does) that it uses any analog pins?

If you're using that shield on a Mega, A4 and A5 don't carry the I2C signals and the I2C connector marked I2C Interface will not carry the I2C signals. So A4/A5 for the Wiegand should not pose an issue.

The I2C interface is available on pins 20/21 of the Mega