Using I2C with Arduino Due and AD7150

@Fraannn101, you are still stuck with the wrong ideas and you can not get further this way.
The pins are not scanned, the SDA is not read.
You should learn about I2C. The SDA and SCL make together the I2C bus (also GND is needed). It is not possible read SDA or SCL, those are the names of the two wires of the I2C bus.