| .. _i2c_api: |
| |
| Inter-Integrated Circuit (I2C) Bus |
| ################################## |
| |
| Overview |
| ******** |
| |
| .. note:: |
| |
| The terminology used in Zephyr I2C APIs follows that of the |
| `NXP I2C Bus Specification Rev 7.0 <i2c-specification_>`_. These changed |
| from previous revisions as of its release October 1, 2021. |
| |
| `I2C <i2c-specification>`_ (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 |
| "controller" that initiates transactions and controls the clock, or as a |
| "target" that responds to transaction commands. A I2C controller on a |
| given SoC will generally support the controller role, and some will also |
| support the target mode. Zephyr has API for both roles. |
| |
| .. _i2c-controller-api: |
| |
| I2C Controller API |
| ================== |
| |
| Zephyr's I2C controller 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-target-api: |
| |
| I2C Target API |
| ============== |
| |
| Zephyr's I2C target 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 controller mode. |
| |
| |
| Configuration Options |
| ********************* |
| |
| Related configuration options: |
| |
| * :kconfig:option:`CONFIG_I2C` |
| |
| API Reference |
| ************* |
| |
| .. doxygengroup:: i2c_interface |
| |
| .. _i2c-specification: |
| https://www.nxp.com/docs/en/user-guide/UM10204.pdf |
