It works on the uno rev3 but the uno2 it doesn't work on. I found the sch for a Rev2 and it doesn't even show any SDA or SCL lines.
but there both ATmega328 So it looks like they should be the same.
It's hooked up like this on both 
It works on the uno rev3 but the uno2 it doesn't work on. I found the sch for a Rev2 and it doesn't even show any SDA or SCL lines.
but there both ATmega328 So it looks like they should be the same.
It's hooked up like this on both