SBAA565 November   2022 ADC081C021 , ADC081C027 , ADC101C021 , ADC101C027 , ADC121C021 , ADC121C021-Q1 , ADC121C027 , ADC128D818 , ADS1000 , ADS1000-Q1 , ADS1013 , ADS1014 , ADS1015 , ADS1015-Q1 , ADS1100 , ADS1110 , ADS1112 , ADS1113 , ADS1114 , ADS1115 , ADS1115-Q1 , ADS7823 , ADS7827 , ADS7828 , ADS7828-Q1 , ADS7830 , ADS7924 , AFE539A4 , DAC081C081 , DAC081C085 , DAC101C081 , DAC101C081Q , DAC101C085 , DAC121C081 , DAC121C085 , DAC43204 , DAC43401 , DAC43401-Q1 , DAC43608 , DAC43701 , DAC43701-Q1 , DAC53002 , DAC53004 , DAC53202 , DAC53204 , DAC53204W , DAC53401 , DAC53401-Q1 , DAC53608 , DAC53701 , DAC53701-Q1 , DAC5571 , DAC5573 , DAC5574 , DAC5578 , DAC60501 , DAC60502 , DAC63002 , DAC63004 , DAC63202 , DAC63204 , DAC6571 , DAC6573 , DAC6574 , DAC6578 , DAC70501 , DAC70502 , DAC7571 , DAC7573 , DAC7574 , DAC7578 , DAC7678 , DAC80501 , DAC80502 , DAC8571 , DAC8574

 

  1.   Abstract
  2.   Trademarks
  3. 1I2C Overview
    1. 1.1 History
    2. 1.2 I2C Speed Modes
  4. 2I2C Physical Layer
    1. 2.1 Two-Wire Communication
    2. 2.2 Open-Drain Connection
    3. 2.3 Non-Destructive Bus Contention
  5. 3I2C Protocol
    1. 3.1 I2C START and STOP
    2. 3.2 Logical Ones and Zeros
    3. 3.3 I2C Communication Frames
  6. 4I2C Examples
    1. 4.1 DAC80501 Example
      1. 4.1.1 DAC80501 DAC Data Register
      2. 4.1.2 DAC80501 I2C Example Write
    2. 4.2 ADS1115 Example
      1. 4.2.1 ADS1115 Configuration Register
      2. 4.2.2 ADS1115 I2C Example Read
      3. 4.2.3 ADS1115 Conversion Result
  7. 5Reserved Addresses
    1. 5.1 General Call
    2. 5.2 START Byte
    3. 5.3 C-Bus Address, Different Bus Format, Future Purposes
    4. 5.4 HS-Mode Controller Code
    5. 5.5 Device ID
    6. 5.6 10-Bit Target Addressing
      1. 5.6.1 10-Bit Target Addressing Write
      2. 5.6.2 10-Bit Target Addressing Read
  8. 6Advanced Topics
    1. 6.1 Clock Synchronization and Arbitration
    2. 6.2 Clock Stretching
    3. 6.3 Electrical Specifications
    4. 6.4 Voltage Level Translation
      1. 6.4.1 Example 1
      2. 6.4.2 Example 2
      3. 6.4.3 Example 3
      4. 6.4.4 Example 4
    5. 6.5 Pullup Resistor Sizing
      1. 6.5.1 Minimum Pullup Resistance Sizing
      2. 6.5.2 Maximum Pullup Resistance Sizing
  9. 7Protocols Similar to I2C
  10. 8Summary

1.1 History

I2C, often called I ‘two’ C, stands for the Inter-Integrated Circuit protocol. I2C was developed in 1982 by Philips Semiconductor (now NXP Semiconductor) as a low-speed communication protocol for connecting controller devices such as microcontrollers and processors with target devices such as data converters and other peripheral devices. Since 2006, implementing the I2C protocol does not require a license, and many semiconductor device companies, including TI, have introduced I2C-compatible devices.

I2C is a widely-used protocol for many reasons. The protocol requires only two lines for communications. Like other serial communication protocols, there is a serial data line and a serial clock line. I2C can connect to multiple devices on the bus with only the two lines. The controller device can communicate with any target device through a unique I2C address sent through the serial data line. I2C is simple and economical for device manufacturers to implement.