I2C pins

On UnoR3 Are the sda/scl Dedicated pins near D13 working differently from A1/A2? I connected a pcf8574 to the pins next to d13 and it didn't work. I then connected the pcf8574 to A1/A2 and it was working. I'm using wire function and the doubt I have that there is way to select which port to use. I also used a second unoR3 just to be sure that the hardware and the addressing was ok.

robademar:
On UnoR3 Are the sda/scl Dedicated pins near D13 working differently from A1/A2?

A1 and A2 aren't I2C pins in the first place.

You mean A4/A5?

Afaik, they're identical to those diagonally opposite.

sorry a4/a5.

If they are symmetrical any idea why is not working?

many thanks anyhow

robademar:
sorry a4/a5.

If they are symmetrical any idea why is not working?

The order is reversed: the ones by D13 has SCL on the left, on the analog pins it's on the right.