Get Started

This document is intended to help users set up the software environment for development of applications using hardware based on the Espressif ESP8266EX. Through a simple example we would like to illustrate how to use ESP8266_RTOS_SDK (ESP-IDF Style), including the menu based configuration, compiling the ESP8266_RTOS_SDK and firmware download to ESP8266EX boards.


The ESP8266EX microcontroller integrates a Tensilica L106 32-bit RISC processor, which achieves extra-low power consumption and reaches a maximum clock speed of 160 MHz. The Real-Time Operating System (RTOS) and Wi-Fi stack allow about 80% of the processing power to be available for user application programming and development.

Espressif provides the basic hardware and software resources that help application developers to build their ideas around the ESP8266EX series hardware. The software development framework by Espressif is intended for rapidly developing Internet-of-Things (IoT) applications, with Wi-Fi, power management and several other system features.

What You Need

To develop applications for ESP8266EX you need:

  • PC loaded with either Windows, Linux or Mac operating system
  • Toolchain to build the Application for ESP8266EX
  • ESP8266_RTOS_SDK that essentially contains API for ESP8266EX and scripts to operate the Toolchain
  • A text editor to write programs (Projects) in C, e.g. Eclipse
  • The ESP8266EX board itself and a USB cable to connect it to the PC
Development of applications for ESP8266EX

Development of applications for ESP8266EX

Preparation of development environment consists of three steps:

  1. Setup of Toolchain
  2. Getting of ESP8266_RTOS_SDK from GitHub
  3. Installation and configuration of Eclipse

You may skip the last step, if you prefer to use different editor.

Having environment set up, you are ready to start the most interesting part - the application development. This process may be summarized in four steps:

  1. Configuration of a Project and writing the code
  2. Compilation of the Project and linking it to build an Application
  3. Flashing (uploading) of the Application to ESP8266EX
  4. Monitoring / debugging of the Application

See instructions below that will walk you through these steps.


If you have one of ESP8266 development boards listed below, click on provided links to get you up and running.

If you have different board, move to sections below.

Setup Toolchain

The quickest way to start development with ESP8266EX is by installing a prebuilt toolchain. Pick up your OS below and follow provided instructions.

windows-logo linux-logo macos-logo
Windows Linux Mac OS


We are using ~/esp directory to install the prebuilt toolchain, ESP8266_RTOS_SDK and sample applications. You can use different directory, but need to adjust respective commands.

Depending on your experience and preferences, instead of using a prebuilt toolchain, you may want to customize your environment..

Once you are done with setting up the toolchain then go to section Get ESP8266_RTOS_SDK.


Besides the toolchain (that contains programs to compile and build the application), you also need ESP8266 specific API / libraries. They are provided by Espressif in ESP8266_RTOS_SDK repository.

To obtain a local copy: open terminal, navigate to the directory you want to put ESP8266_RTOS_SDK, and clone the repository using git clone command:

cd ~/esp
git clone --recursive

ESP8266_RTOS_SDK will be downloaded into ~/esp/ESP8266_RTOS_SDK.


This command will clone the master branch, which has the latest development (“bleeding edge”) version of ESP8266_RTOS_SDK. It is fully functional and updated on weekly basis with the most recent features and bugfixes.


GitHub’s “Download zip file” feature does not work with ESP8266_RTOS_SDK, a git clone is required. As a fallback, Stable version can be installed without Git.

Setup Path to ESP8266_RTOS_SDK

The toolchain programs access ESP8266_RTOS_SDK using IDF_PATH environment variable. This variable should be set up on your PC, otherwise projects will not build. Setting may be done manually, each time PC is restarted. Another option is to set up it permanently by defining IDF_PATH in user profile.

Install the Required Python Packages

Python packages required by ESP8266_RTOS_SDK are located in the $IDF_PATH/requirements.txt file. You can install them by running:

python -m pip install --user -r $IDF_PATH/requirements.txt


Please invoke that version of the Python interpreter which you will be using with ESP8266_RTOS_SDK. The version of the interpreter can be checked by running command python --version and depending on the result, you might want to use python2, python2.7 or similar instead of python, e.g.:

python2.7 -m pip install --user -r $IDF_PATH/requirements.txt

Start a Project

Now you are ready to prepare your application for ESP8266. To start off quickly, we will use get-started/hello_world project from examples directory in IDF.

Copy get-started/hello_world to ~/esp directory:

cd ~/esp
cp -r $IDF_PATH/examples/get-started/hello_world .

You can also find a range of example projects under the examples directory in ESP-IDF. These example project directories can be copied in the same way as presented above, to begin your own projects.


The ESP8266_RTOS_SDK build system does not support spaces in paths to ESP8266_RTOS_SDK or to projects.


You are almost there. To be able to proceed further, connect ESP8266 board to PC, check under what serial port the board is visible and verify if serial communication works. Note the port number, as it will be required in the next step.


Being in terminal window, go to directory of hello_world application by typing cd ~/esp/hello_world. Then start project configuration utility menuconfig:

cd ~/esp/hello_world
make menuconfig

If previous steps have been done correctly, the following menu will be displayed:

Project configuration - Home window

Project configuration - Home window

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 application by selecting < Exit >.


On Windows, serial ports have names like COM1. On MacOS, they start with /dev/cu.. On Linux, they start with /dev/tty.

Here are couple of tips on navigation and use of menuconfig:

  • Use up & down arrow keys to navigate the menu.
  • Use Enter key to go into a submenu, Escape key to go out or to exit.
  • Type ? to see a help screen. Enter key exits the help screen.
  • Use Space key, or Y and N keys to enable (Yes) and disable (No) configuration items with checkboxes “[*]
  • Pressing ? while highlighting a configuration item displays help about that item.
  • Type / to search the configuration items.


If you are Arch Linux user, navigate to SDK tool configuration and change the name of Python 2 interpreter from python to python2.

Build and Flash

Now you can build and flash the application. Run:

make flash

This will compile the application and all the ESP8266_RTOS_SDK components, generate bootloader, partition table, and application binaries, and flash these binaries to your ESP8266 board. v2.4.0
Flashing binaries to serial port /dev/ttyUSB0 (app at offset 0x10000)... v2.4.0
Chip is ESP8266EX
Features: WiFi
MAC: ec:fa:bc:1d:33:2d
Uploading stub...
Running stub...
Stub running...
Configuring flash size...
Compressed 7952 bytes to 5488...
Wrote 7952 bytes (5488 compressed) at 0x00000000 in 0.5 seconds (effective 129.9 kbit/s)...
Hash of data verified.
Compressed 234800 bytes to 162889...
Wrote 234800 bytes (162889 compressed) at 0x00010000 in 14.4 seconds (effective 130.6 kbit/s)...
Hash of data verified.
Compressed 3072 bytes to 83...
Wrote 3072 bytes (83 compressed) at 0x00008000 in 0.0 seconds (effective 1789.8 kbit/s)...
Hash of data verified.

Hard resetting via RTS pin...

If there are no issues, at the end of build process, you should see messages describing progress of loading process. Finally, the end module will be reset and “hello_world” application will start.

If you’d like to use the Eclipse IDE instead of running make, check out the Eclipse guide.


To see if “hello_world” application is indeed running, type make monitor.

$ make monitor MONITOR — idf_monitor on /dev/ttyUSB0 74880 — — Quit: Ctrl+] | Menu: Ctrl+T | Help: Ctrl+T followed by Ctrl+H —

ets Jan 8 2013,rst cause:1, boot mode:(3,6)

load 0x40100000, len 4400, room 16 0x40100000: _stext at ??:?

tail 0 chksum 0x6f load 0x3ffe8408, len 3516, room 8 tail 4 chksum 0x5d …

Several lines below, after start up and diagnostic log, you should see “SDK version: xxxxxxx” printed out by the application.

SDK version:v3.1-dev-311-g824cd8c8-dirty

To exit the monitor use shortcut Ctrl+].


If instead of the messages above, you see a random garbage similar to:

~zY��Y(1�,1�� e���)(Xn@�y.!Dr�zY(�jpi�|�+z5Ymvp

To execute make flash and make monitor in one go, type make flash monitor.

That’s all what you need to get started with ESP8266!

Now you are ready to try some other examples, or go right to developing your own applications.

Environment Variables

Some environment variables can be specified whilst calling make allowing users to override arguments without needing to reconfigure them using make menuconfig.

Variables Description & Usage

Overrides the serial port used in flash and monitor.

Examples: make flash ESPPORT=/dev/ttyUSB1, make monitor ESPPORT=COM1


Overrides the serial baud rate when flashing the ESP32.

Example: make flash ESPBAUD=9600


Overrides the serial baud rate used when monitoring.

Example: make monitor MONITORBAUD=9600


Users can export environment variables (e.g. export ESPPORT=/dev/ttyUSB1). All subsequent calls of make within the same terminal session will use the exported value given that the variable is not simultaneously overridden.