.. _esp32s2_saola:

ESP32-S2
########

Overview
********

ESP32-S2 is a highly integrated, low-power, single-core Wi-Fi Microcontroller SoC, designed to be secure and
cost-effective, with a high performance and a rich set of IO capabilities. [1]_

The features include the following:

- RSA-3072-based secure boot
- AES-XTS-256-based flash encryption
- Protected private key and device secrets from software access
- Cryptographic accelerators for enhanced performance
- Protection against physical fault injection attacks
- Various peripherals:

  - 43x programmable GPIOs
  - 14x configurable capacitive touch GPIOs
  - USB OTG
  - LCD interface
  - camera interface
  - SPI
  - I2S
  - UART
  - ADC
  - DAC

System requirements
*******************

Prerequisites
-------------

Espressif HAL requires binary blobs in order work. The west extension below performs the required
syncronization to clone, checkout and pull the submodules:

.. code-block:: console

   west espressif update

.. note::

   It is recommended running the command above after :file:`west update`.

Building & Flashing
-------------------

Build and flash applications as usual (see :ref:`build_an_application` and
:ref:`application_run` for more details).

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: esp32s2_saola
   :goals: build

The usual ``flash`` target will work with the ``esp32s2_saola`` board
configuration. Here is an example for the :ref:`hello_world`
application.

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: esp32s2_saola
   :goals: flash

Open the serial monitor using the following command:

.. code-block:: shell

   west espressif monitor

After the board has automatically reset and booted, you should see the following
message in the monitor:

.. code-block:: console

   ***** Booting Zephyr OS vx.x.x-xxx-gxxxxxxxxxxxx *****
   Hello World! esp32s2_saola

Debugging
---------

As with much custom hardware, the ESP32S2 modules require patches to
OpenOCD that are not upstreamed. Espressif maintains their own fork of
the project. The custom OpenOCD can be obtained by running the following extension:

.. code-block:: console

   west espressif install

.. note::

   By default, the OpenOCD will be downloaded and installed under $HOME/.espressif/tools/zephyr directory
   (%USERPROFILE%/.espressif/tools/zephyr on Windows).

The Zephyr SDK uses a bundled version of OpenOCD by default. You can overwrite that behavior by adding the
``-DOPENOCD=<path/to/bin/openocd> -DOPENOCD_DEFAULT_PATH=<path/to/openocd/share/openocd/scripts>``
parameter when building.

Here is an example for building the :ref:`hello_world` application.

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: esp32s2_saola
   :goals: build flash
   :gen-args: -DOPENOCD=<path/to/bin/openocd> -DOPENOCD_DEFAULT_PATH=<path/to/openocd/share/openocd/scripts>

You can debug an application in the usual way. Here is an example for the :ref:`hello_world` application.

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: esp32s2_saola
   :goals: debug

References
**********

.. [1] https://www.espressif.com/en/products/socs/esp32-s2
.. _`ESP32S2 Technical Reference Manual`: https://espressif.com/sites/default/files/documentation/esp32-s2_technical_reference_manual_en.pdf
.. _`ESP32S2 Datasheet`: https://www.espressif.com/sites/default/files/documentation/esp32-s2_datasheet_en.pdf