For 10 bit addressing you can look up the official I2C specification by NXP, a link to which is given at the bottom of this tutorial. To keep things simple we will be going through 7 bit addressing in this tutorial. With 10 bit address a maximum of 1024 devices can be connected. With 7 bit address its possible to connect up to 128 I2C devices to the same bus, however, some addresses are reserved so practically only 112 devices can be connected at the same time. I2C supports 7 bit and 10 bit addresses for each device connected to the bus. SCL is the wire on which the Master device generates a clock for slave device(s).

SDA is the wire on which the actual data transfer happens, which is bi-directional, between different masters and slaves. Clock Line called SCL which is short for Serial Clock Data Line called SDA which is short for Serial DataĢ. I2C is pronounced and referred to as “I-Squared-C”, “I-Two-C” and “I-I-C”. I2C is sometimes also referred as TWI, which is short for Two Wire Interface, since it uses only 2 wires for data transmission and synchronization. I2C was originally invented by Philips(now NXP) in 1982 as bi-directional bus to communicate with multiple devices using just 2 wires/lines. In this tutorial we will go through I2C Bus & Protocol.

Arduino wire library repeated start