I2C Overview

• Introduction
• Available APIs

Introduction

• The Inter-Integrated Circuit (I2C) is a simple, bidirectional, and synchronous serial bus that uses merely two wires.

• In an I2C communication, one controller communicates with one or more devices through the serial data line (SDA) and serial clock line (SCL), as shown in Figure 1.

• I2C data transfer must begin with a START condition and end with a STOP condition. Data is transmitted byte-by-byte from the most significant bit to the least significant bit.

• Each I2C node is recognized by a unique address and can serve as either a controller or a device. When the controller needs to communicate with a device, it writes the device address to the bus through broadcast. A device matching this address sends a response to set up a data transfer channel.

• The I2C APIs define a set of common functions for I2C data transfer, including:

  • I2C controller management: opening or closing an I2C controller
  • I2C message transfer: custom transfer by using a message array

  Figure 1 Physical connection diagram for I2C
  

Available APIs

Table 1 APIs available for the I2C driver

NOTE: All functions provided in this document can be called only in kernel mode.