.. _i2c_api: I2C #### Overview ******** .. note:: Zephyr recognizes the need to change the terms "master" and "slave" used in the current `I2C Specification `_. This will be done when the conditions identified in :ref:`coding_guideline_inclusive_language` have been met. Existing documentation, data structures, functions, and value symbols in code are likely to change at that point. `I2C `_ (Inter-Integrated Circuit, pronounced "eye squared see") is a commonly-used two-signal shared peripheral interface bus. Many system-on-chip solutions provide controllers that communicate on an I2C bus. Devices on the bus can operate in two roles: as a "master" that initiates transactions and controls the clock, or as a "slave" that responds to transaction commands. A I2C controller on a given SoC will generally support the master role, and some will also support the slave mode. Zephyr has API for both roles. .. _i2c-master-api: I2C Master API ============== Zephyr's I2C master API is used when an I2C peripheral controls the bus, in particularly the start and stop conditions and the clock. This is the most common mode, used to interact with I2C devices like sensors and serial memory. This API is supported in all in-tree I2C peripheral drivers and is considered stable. .. _i2c-slave-api: I2C Slave API ================ Zephyr's I2C slave API is used when an I2C peripheral responds to transactions initiated by a different controller on the bus. It might be used for a Zephyr application with transducer roles that are controlled by another device such as a host processor. This API is supported in very few in-tree I2C peripheral drivers. The API is considered experimental, as it is not compatible with the capabilities of all I2C peripherals supported in master mode. Configuration Options ********************* Related configuration options: * :kconfig:`CONFIG_I2C` API Reference ************* .. doxygengroup:: i2c_interface .. _i2c-specification: https://www.nxp.com/docs/en/user-guide/UM10204.pdf