After that, a simple example will show you how to use ESP-IDF (Espressif IoT Development Framework) for menu configuration, then for building and flashing firmware onto an ESP32 board.
Powered by 40 nm technology, ESP32 provides a robust, highly integrated platform, which helps meet the continuous demands for efficient power usage, compact design, security, high performance, and reliability.
Espressif provides basic hardware and software resources to help application developers realize their ideas using the ESP32 series hardware. The software development framework by Espressif is intended for development of Internet-of-Things (IoT) applications with Wi-Fi, Bluetooth, power management and several other system features.
What You Need
=============
Hardware:
* An **ESP32** board
***USB cable** - USB A / micro USB B
***Computer** running Windows, Linux, or macOS
Software:
***Toolchain** to build the **Application** for ESP32
***ESP-IDF** that essentially contains API (software libraries and source code) for ESP32 and scripts to operate the **Toolchain**
***Text editor** to write programs (**Projects**) in C, e.g., `Eclipse <https://www.eclipse.org/>`_
..figure:: ../../_static/what-you-need.png
:align:center
:alt:Development of applications for ESP32
:figclass:align-center
Development of applications for ESP32
Development Board Overviews
===========================
If you have one of ESP32 development boards listed below, you can click on the link to learn more about its hardware.
This guide uses the directory ``~/esp`` on Linux and macOS or ``%userprofile%\esp`` on Windows as an installation folder for ESP-IDF. You can use any directory, but you will need to adjust paths for the commands respectively. Keep in mind that ESP-IDF does not support spaces in paths.
Depending on your experience and preferences, you may want to customize your environment instead of using a prebuilt toolchain. To set up the system your own way go to Section :ref:`get-started-customized-setup-legacy`.
Besides the toolchain, you also need ESP32-specific API (software libraries and source code). They are provided by Espressif in `ESP-IDF repository <https://github.com/espressif/esp-idf>`_.
To get a local copy of ESP-IDF, navigate to your installation directory and clone the repository with ``git clone``.
The toolchain uses the environment variable ``IDF_PATH`` to access the ESP-IDF directory. This variable should be set up on your computer, otherwise projects will not build.
These variables can be set temporarily (per session) or permanently. Please follow the instructions specific to :ref:`Windows <add-idf_path-to-profile-windows-legacy>` , :ref:`Linux and macOS <add-idf_path-to-profile-linux-macos-legacy>` in Section :doc:`add-idf_path-to-profile`.
Now you are ready to prepare your application for ESP32. You can start with :example:`get-started/hello_world` project from :idf:`examples` directory in IDF.
Copy :example:`get-started/hello_world` to the ``~/esp`` directory:
There is a range of example projects in the :idf:`examples` directory in ESP-IDF. You can copy any project in the same way as presented above and run it.
It is also possible to build examples in-place, without copying them first.
..important::
The esp-idf build system does not support spaces in the paths to either esp-idf or to projects.
In the menu, navigate to ``Serial flasher config`` > ``Default serial port`` to configure the serial port, where project will be loaded to. Confirm selection by pressing enter, save configuration by selecting ``< Save >`` and then exit ``menuconfig`` by selecting ``< Exit >``.
To navigate and use ``menuconfig``, press the following keys:
* Arrow keys for navigation
*``Enter`` to go into a submenu
*``Esc`` to go up one level or exit
*``?`` to see a help screen. Enter key exits the help screen
*``Space``, or ``Y`` and ``N`` keys to enable (Yes) and disable (No) configuration items with checkboxes "``[*]``"
*``?`` while highlighting a configuration item to display help about that item
*``/`` to find configuration items
..attention::
If you use ESP32-DevKitC board with the **ESP32-SOLO-1** module, enable single core mode (:ref:`CONFIG_FREERTOS_UNICORE`) in menuconfig before flashing examples.
This command will compile the application and all ESP-IDF components, then it will generate the bootloader, partition table, and application binaries. After that, these binaries will be flashed onto your ESP32 board.
If you run the given command and see errors such as "Failed to connect", there might be several reasons for this. One of the reasons might be issues encountered by ``esptool.py``, the utility that is called by the build system to reset the chip, interact with the ROM bootloader, and flash firmware. One simple solution to try is manual reset described below, and if it does not help you can find more details about possible issues in `Troubleshooting <https://github.com/espressif/esptool#bootloader-wont-respond>`_.
``esptool.py`` resets {IDF_TARGET_NAME} automatically by asserting DTR and RTS control lines of the USB to serial converter chip, i.e., FTDI or CP210x (for more information, see :doc:`establish-serial-connection`). The DTR and RTS control lines are in turn connected to ``GPIO0`` and ``CHIP_PU`` (EN) pins of {IDF_TARGET_NAME}, thus changes in the voltage levels of DTR and RTS will boot {IDF_TARGET_NAME} into Firmware Download mode. As an example, check the schematic for :ref:`esp-modules-and-boards-esp32-devkitc` development board.
In general, you should have no problems with the official esp-idf development boards. However, ``esptool.py`` is not able to reset your hardware automatically in the following cases:
- Your hardware does not have the DTR and RTS lines connected to ``GPIO0`` and ``CIHP_PU``
- The DTR and RTS lines are configured differently
- There are no such serial control lines at all
Depending on the kind of hardware you have, it may also be possible to manually put your {IDF_TARGET_NAME} board into Firmware Download mode (reset).
- For development boards produced by Espressif, this information can be found in the respective getting started guides or user guides. For example, to manually reset an esp-idf development board, hold down the **Boot** button (``GPIO0``) and press the **EN** button (``CHIP_PU``).
- For other types of hardware, try pulling ``GPIO0`` down.
If there are no issues by the end of the flash process, you will see the output log similar to the one given below. Then the board will reboot and start up the "hello_world" application.
If IDF monitor fails shortly after the upload, or if instead of the messages above you see a random garbage similar to what is given below, your board is likely using a 26MHz crystal. Most development board designs use 40MHz, so ESP-IDF uses this frequency as a default value.
You can combine building, flashing and monitoring into one step by running::
make flash monitor
See also :doc:`IDF Monitor <../api-guides/tools/idf-monitor>` for handy shortcuts and more details on using IDF monitor.
**That's all that you need to get started with ESP32!**
Now you are ready to try some other :idf:`examples`, or go straight to developing your own applications.
Environment Variables
=====================
Some environment variables can be specified whilst calling ``make`` allowing users to **override arguments without the need to reconfigure them using**``make menuconfig``.
You should update ESP-IDF from time to time, as newer versions fix bugs and provide new features. The simplest way to do the update is to delete the existing ``esp-idf`` folder and clone it again, as if performing the initial installation described in :ref:`get-started-get-esp-idf-legacy`.
If downloading to a new path, remember to :doc:`add-idf_path-to-profile` so that the toolchain scripts can find ESP-IDF in its release specific location.
Another solution is to update only what has changed. :ref:`The update procedure depends on the version of ESP-IDF you are using <updating>`.
