I know similar question has already been discussed here but I could not get clear answer. Here is the thing: I have one master device - Mega2560, and multiple (about 9 but could be expandedin future) I2C perfiferals - displays, that can have one of two possible I2C IDs - limitation by the manufacturer. As I can't connect and talk to them from a single I2C bus I chose to attach each two of them to a Mini-Pro's I2C pins and connect the 5 Mini-Pros to the master. The question is am I going to the right direction, and which connection would do the trick? I2C is obviously out of question, so the remaining are UART and SPI. UART would require some external hardware to cope with multiple outputs from the slaves, SPI would require additional pins from the master for chip select signal. Data rates are not high - min 10-20 kbps. I think the SPI offers better solution, but I'm no expert, what do you think?