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I2C Communication Protocol

A versatile and widely used two-wire communication protocol for connecting low-speed devices in embedded systems.


 30 April 2024   |     1 minute read   |   By Kevin McAleer   |   Share this article on

What is I2C?

I2C, or Inter-Integrated Circuit, is a serial communication protocol that allows multiple slave devices to be controlled by a single or multiple master devices. It uses only two wires, making it ideal for connecting peripherals like sensors, displays, and other microcontrollers with minimal wiring.


Description

I2C uses two lines: SDA (Serial Data Line) and SCL (Serial Clock Line), to communicate between devices. It supports multiple masters and slaves, addressing each device uniquely through 7-bit or 10-bit addressing.


Key Features of I2C

  • Two-Wire Interface: Only uses two wires, reducing complexity in system design.
  • Multi-Master Capability: Allows multiple master devices to control the bus.
  • Clock Stretching: Slaves can slow down communication by holding the clock line low.
  • Arbitration: Prevents data collision by allowing only one master to control the bus at a time.
  • Addressing: Supports up to 112 devices on the same bus with 7-bit addressing.

Application Areas

Consumer Electronics: Used in smartphones, televisions, and other smart devices to control auxiliary components like sensors and touch screens.

Automotive Systems: Employed in vehicle internal networks to communicate with sensors and control systems.

Industrial Automation: Integral in managing communication between various sensors and actuaries in automated systems.


Conventions

I2C is typically used in environments where communication simplicity and cost-effectiveness are prioritized over speed. It is suitable for applications where devices are relatively close to each other.


Pros and Cons

Pros:

  • Simple and efficient for small-scale communication.
  • Reduces wiring complexity significantly.
  • Scalable to a reasonable number of devices without additional hardware.

Cons:

  • Limited by bus speed and length, which affects the number of devices and response times.
  • Susceptible to interference in noisy environments.
  • Requires careful handling of bus arbitration and clock synchronization.