I'm developing a sketch which uses the I2C bus with pins 17 and 16 on a Uno R3. The I2C I/O is working fine with the real time clock DS3231 as well as PIO device PCF8574.
I hit problems when I started to use A4 and A5 as simple LED outputs. The outputs are stuck high when I include execution of Wire.begin();.
I refer to the Wire library reference on this site which says that on Uno boards A4 and A5 are SDA and SCL repectively.
But I'm using the pins 16 and 17 successfully!(?)
If there are 2 busses available then how are they selected?
In anycase is there a way of freeing up A4 and A5 for GPIO when Wire library is also used?
Thanks for any help or advice...