I2C
I2C (Inter-Integrated Circuit) is a synchronous, multi-master, multi-slave, packet-switched, single-ended, serial communication bus invented by Philips Semiconductor (now NXP Semiconductors). It is widely used for attaching lower-speed peripheral ICs to processors and microcontrollers in short-distance, intra-board communication, such as sensors, EEPROMs, and real-time clocks. The protocol uses two bidirectional open-drain lines: Serial Data (SDA) and Serial Clock (SCL), pulled up with resistors, to enable communication between devices on the same bus.
Developers should learn I2C when working with embedded systems, IoT devices, or hardware projects that require communication between multiple integrated circuits on a single board, as it simplifies wiring and reduces pin count compared to parallel interfaces. It is ideal for scenarios where moderate data rates (typically up to 3.4 Mbps in high-speed mode) and short distances are sufficient, such as reading sensor data, configuring peripherals, or managing memory chips. Its multi-master capability allows for flexible system designs where multiple controllers can share the bus.