.. _esp32c3_devkitm:

ESP32-C3
########

Overview
********

ESP32-C3 is a single-core Wi-Fi and Bluetooth 5 (LE) microcontroller SoC,
based on the open-source RISC-V architecture. It strikes the right balance of power,
I/O capabilities and security, thus offering the optimal cost-effective
solution for connected devices.
The availability of Wi-Fi and Bluetooth 5 (LE) connectivity not only makes the device configuration easy,
but it also facilitates a variety of use-cases based on dual connectivity. [1]_

The features include the following:

- 32-bit core RISC-V microcontroller with a maximum clock speed of 160 MHz
- 400 KB of internal RAM
- 802.11b/g/n/e/i
- A Bluetooth LE subsystem that supports features of Bluetooth 5 and Bluetooth mesh
- Various peripherals:

  - 12-bit ADC with up to 6 channels
  - TWAI compatible with CAN bus 2.0
  - Temperature sensor
  - 3x SPI
  - 1x I2S
  - 1x I2C
  - 2x UART
  - LED PWM with up to 6 channels

- Cryptographic hardware acceleration (RNG, ECC, RSA, SHA-2, AES)

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

Current Zephyr's ESP32-C3-Devkitm 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                                 |
+------------+------------+-------------------------------------+
| SPI DMA    | on-chip    | spi                                 |
+------------+------------+-------------------------------------+
| TWAI       | on-chip    | can                                 |
+------------+------------+-------------------------------------+
| USB-CDC    | on-chip    | serial                              |
+------------+------------+-------------------------------------+
| ADC        | on-chip    | adc                                 |
+------------+------------+-------------------------------------+
| Wi-Fi      | on-chip    |                                     |
+------------+------------+-------------------------------------+
| Bluetooth  | 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: esp32c3_devkitm
   :goals: build

The usual ``flash`` target will work with the ``esp32c3_devkitm`` board
configuration. Here is an example for the :ref:`hello_world`
application.

.. zephyr-app-commands::
   :zephyr-app: samples/hello_world
   :board: esp32c3_devkitm
   :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! esp32c3_devkitm

Debugging
---------

As with much custom hardware, the ESP32-C3 modules require patches to
OpenOCD that are not upstreamed yet. Espressif maintains their own fork of
the project. The custom OpenOCD can be obtained at `OpenOCD ESP32`_

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: esp32c3_devkitm
   :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: esp32c3_devkitm
   :goals: debug

.. _`OpenOCD ESP32`: https://github.com/espressif/openocd-esp32/releases

References
==========

.. [1] https://www.espressif.com/en/products/socs/esp32-c3
.. _ESP32C3 Devkitm User Guide: https://docs.espressif.com/projects/esp-idf/en/latest/esp32c3/hw-reference/esp32c3/user-guide-devkitm-1.html
.. _ESP32C3 Technical Reference Manual: https://espressif.com/sites/default/files/documentation/esp32-c3_technical_reference_manual_en.pdf
.. _ESP32C3 Datasheet: https://www.espressif.com/sites/default/files/documentation/esp32-c3_datasheet_en.pdf