Patrick,

Aren't the I²C addressing modes 7-bit and 10-bit?

As a comment to what Erik said: SPI can be used with only 2 wires, if only one device is used and only simplex communication is required. Otherwise 3 wires are required for data (SDI, SDO, SCK) plus a means to select the peripheral device, which can be done via an I/O pin or with some form of logic or decoding.

SPI is easier and faster, more I/O. I²C is better for multiple devices at lower speeds with less I/O. I often use SPI for it's speed, but I will use I²C when appropriate. I like I²C for it's serial addressing capability, very useful.

Cory Spackman