.. _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
  - LED PWM with up to 8 channels

Supported Features
==================

Current Zephyr's ESP32-S2-saola board supports the following features:

+------------+------------+-------------------------------------+
| Interface  | Controller | Driver/Component                    |
+============+============+=====================================+
+------------+------------+-------------------------------------+
| UART       | on-chip    | serial port                         |
+------------+------------+-------------------------------------+
| GPIO       | on-chip    | gpio                                |
+------------+------------+-------------------------------------+
| PINMUX     | on-chip    | pinmux                              |
+------------+------------+-------------------------------------+
| USB-JTAG   | on-chip    | hardware interface                  |
+------------+------------+-------------------------------------+
| SPI Master | on-chip    | spi                                 |
+------------+------------+-------------------------------------+
| Timers     | on-chip    | counter                             |
+------------+------------+-------------------------------------+
| Watchdog   | on-chip    | watchdog                            |
+------------+------------+-------------------------------------+
| TRNG       | on-chip    | entropy                             |
+------------+------------+-------------------------------------+
| LEDC       | on-chip    | pwm                                 |
+------------+------------+-------------------------------------+
| PCNT       | on-chip    | qdec                                |
+------------+------------+-------------------------------------+
| SPI DMA    | on-chip    | spi                                 |
+------------+------------+-------------------------------------+
| ADC        | on-chip    | adc                                 |
+------------+------------+-------------------------------------+
| DAC        | on-chip    | dac                                 |
+------------+------------+-------------------------------------+
| Wi-Fi      | on-chip    |                                     |
+------------+------------+-------------------------------------+

System requirements
===================

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

Espressif HAL requires WiFi and Bluetooth binary blobs in order work. Run the command
below to retrieve those files.

.. code-block:: console

   west blobs fetch hal_espressif

.. 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
---------

ESP32-S2 support on OpenOCD is available upstream as of version 0.12.0.
Download and install OpenOCD from `OpenOCD`_.

The following table shows the pin mapping between ESP32-S2 board and JTAG interface.

+---------------+-----------+
| ESP32 pin     | JTAG pin  |
+===============+===========+
| MTDO / GPIO40 | TDO       |
+---------------+-----------+
| MTDI / GPIO41 | TDI       |
+---------------+-----------+
| MTCK / GPIO39 | TCK       |
+---------------+-----------+
| MTMS / GPIO42 | TMS       |
+---------------+-----------+

Further documentation can be obtained from the SoC vendor in `JTAG debugging for ESP32-S2`_.

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

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

.. _`OpenOCD`: https://github.com/openocd-org/openocd
.. _`JTAG debugging for ESP32-S2`: https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/api-guides/jtag-debugging/index.html


References
**********

.. [1] https://www.espressif.com/en/products/socs/esp32-s2
.. _ESP32-S2 Saola User Guide: https://docs.espressif.com/projects/esp-idf/en/latest/esp32s2/hw-reference/esp32s2/user-guide-saola-1-v1.2.html
.. _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