.. include:: ../substitutions.rst

I2C
===

The Inter-Integrated Circuit (I2C) interface is a two-wire, bidirectional serial bus that provides a simple and efficient method for data exchange among devices. The |product| provides independent multimaster fast-mode I2C modules. This guide will show you how to test the I2C interface on the |product-cb|. To learn more information about the |product| I2C interface, please see the I2C section in the |hw-manual-link|.

.. note::
        Only a subset of I2C interfaces are supported on the |product-cb| by default but others can be enabled via pin multiplexing.

.. list-table:: I2C Settings
   :header-rows: 1

   * - Hardware Interface
     - sysfs Path
   * - WKUP_I2C0
     - /dev/i2c-0
   * - I2C0
     - /dev/i2c-1
   * - I2C1
     - /dev/i2c-2


Scanning the I2C Buses
----------------------

* Power on the |product-cb| and boot into Linux.

* List the available I2C devices. Each ``/dev/i2c-*`` entry corresponds to one of the I2C interfaces in the table above.

.. code-block:: console
    :caption: List I2C devices
    :substitutions:

    |target-prompt| ls /dev/i2c*

* Use the ``i2cdetect`` command to scan each bus for devices. WKUP_I2C0 carries the SOM's own devices (PMIC, EEPROMs, RTC). I2C0 is exposed on the X28 expansion header and has no carrier-board devices by default. I2C1 carries the carrier-board peripherals.

.. jinja::
   :file: ../templates/interfaceguides/i2c-scan.jinja

.. note::
        UU indicates that the device with that particular address is tied to a kernel driver and you will be unable to communicate with the device via i2c commands (i2cset and i2cget).

The detected interfaces on WKUP_I2C0 and I2C1 correspond to:

.. jinja::
   :file: ../templates/interfaceguides/i2c-device-table.jinja

.. note::
    The list of visible I2C devices in your output may differ from what is shown above. This is because our System on Modules (SoMs) come in different variants, and some devices (like the RTC) are optional depending on the specific variant you are using.