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.. _i2c_config:

I²C Configuration
=================

Follow the steps below to enable and test the I²C interface on your Raspberry Pi.  
These instructions apply to Raspberry Pi 5, 4, 3, and Zero 2W.

Enable the I²C Interface
------------------------

#. Open a terminal on your computer (Windows: **PowerShell**; macOS/Linux: **Terminal**) and connect to your Raspberry Pi:

   .. code-block:: bash

      ssh <username>@<hostname>.local

   or:

   .. code-block:: bash

      ssh <username>@<ip_address>

#. Open the Raspberry Pi configuration tool:

   .. code-block:: bash

      sudo raspi-config

#. Select **Interfacing Options** and press **Enter**.

   .. image:: /_shared/appendix/img/ssh_interface.png
      :align: center

#. Select **I2C**.

   .. image:: img/ssh_i2c_i2c.png
      :align: center

#. Choose **<Yes>**, then **<Ok> → <Finish>** to apply the changes.  
   If prompted, reboot your Raspberry Pi.

   .. image:: img/ssh_i2c_yes.png
      :align: center


Check I²C Kernel Modules
------------------------

#. Run the following command:

   .. code-block:: bash

      lsmod | grep i2c

#. If I²C is enabled, you will see modules such as:

   .. code-block:: text

      i2c_dev        6276    0
      i2c_bcm2708    4121    0

#. If nothing appears, reboot the system:

   .. code-block:: bash

      sudo reboot


Install i2c-tools
-----------------

#. Install the utilities required for scanning and testing I²C devices:

   .. code-block:: bash

      sudo apt install i2c-tools


Detect Connected I²C Devices
----------------------------

#. Scan the I²C bus:

   .. code-block:: bash

      i2cdetect -y 1

#. Example output:

   .. code-block:: text

      pi@raspberrypi ~ $ i2cdetect -y 1
          0  1  2  3   4  5  6  7  8  9   a  b  c  d  e  f
      00:           -- -- -- -- -- -- -- -- -- -- -- -- --
      10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      40: -- -- -- -- -- -- -- -- 48 -- -- -- -- -- -- --
      50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
      70: -- -- -- -- -- -- -- --

#. If a device is connected, its address (e.g., **0x48**) will appear in the table.


Install the Python I²C Library
------------------------------

#. Install the ``python3-smbus2`` package:

   .. code-block:: bash

      sudo apt install python3-smbus2

   The ``smbus2`` library provides all the functions required to communicate with I²C devices in Python.

Your Raspberry Pi is now fully configured and ready to communicate with I²C devices.