What is I2C Inter-Integrated Circuit? Explanation of basic concepts of data communication

Explanation of IT Terms

What is I2C Inter-Integrated Circuit? Explanation of basic concepts of data communication


I2C, which stands for Inter-Integrated Circuit, is a widely used serial communication protocol that enables data transfer between microcontrollers and peripheral devices. Developed by Philips (now NXP Semiconductors) in the 1980s, I2C has become the go-to choice for connecting devices in various applications, ranging from consumer electronics to industrial automation.

Understanding I2C

I2C is a master-slave communication protocol, meaning that there is one main device (the master) that initiates and controls the communication, and one or more peripheral devices (the slaves) that respond to the master’s requests. It uses a two-wire interface consisting of a serial data line (SDA) and a serial clock line (SCL).

The master generates the clock signal and controls the timing of data transfer on the bus. It initiates communication by sending a start condition and terminates it with a stop condition. The slaves, on the other hand, listen for requests from the master and respond accordingly.

Data Transfer and Addressing

I2C uses a 7-bit or 10-bit addressing scheme to identify individual slave devices on the bus. The first byte transmitted by the master after the start condition contains the slave’s address, followed by a read/write bit that indicates the direction of data transfer.

Once communication is established, data transfer occurs in bytes. The master sends a byte to a specific slave, which acknowledges the receipt of the data. The slave can also respond with data, which the master acknowledges. This byte-by-byte transfer allows for efficient use of the bus and enables communication between multiple devices.

Advantages of I2C

One of the key advantages of I2C is its simplicity, requiring only two wires for communication. This makes it suitable for connecting multiple devices in a system while minimizing the number of pins required. Additionally, I2C supports multiple masters and allows for easy device integration, as many peripheral devices in the market offer I2C interfaces.

Another advantage is the built-in arbitration mechanism in the protocol. In case two or more masters attempt to transmit data simultaneously, the arbitration mechanism ensures that only one master wins the bus and completes the transfer. This feature enhances the reliability of the communication system.


I2C is a versatile and widely adopted communication protocol that enables efficient data transfer between microcontrollers and peripheral devices. Its simplicity, support for multiple masters, and built-in arbitration mechanism make it an attractive choice in various applications. Understanding the basics of I2C is essential for anyone involved in developing or troubleshooting systems that rely on this communication protocol.

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