* Replace the SDK's use of ets_intr_lock/unlock with nestable versions Testing has shown that there are several paths in the SDK that result in nested calls to ets_intr_lock() / ets_intr_unlock() which may be a problem. These functions also do not preserve the enabled interrupt level and may result in code running with interrupts enabled when that is not intended. This issue has recently been fixed in the Arduino code by using xt_rsil() / xt_wsr_ps() but still exists in the Espressif SDK code. This commit is intended to fix that and should be used in addition to the above. The maximum nesting I have seen is 2 and lock/unlock calls appear to be balanced. A max of 7 levels of nesting leaves plenty of room for that to change. * make ets_intr_lock_stack uint16_t and behave like the original on over/underflow The PS register is 15 bits, we should store the whole thing as xt_wsr_ps() writes the whole thing. Also if there is an underflow, we should make sure interrupts are enabled. Same goes for overflow making sure interrupts are disabled, although this is less important. * Rename ets_intr_(un)lock_nest to ets_intr_(un)lock This saves having to modify libmain.a, libpp.a and libnet80211.a to use the nested versions. Adjusts fix_sdk_libs.sh accordingly. * Remove ets_intr_(un)lock from the rom .ld as we no longer use them * ets_post() wrapper to preserve interrupt state Add a wrapper around the ets_post code in rom to preserve the interrupt enable state. Rather than modifying the SDK libs, rename ets_post in the .ld file and call the wrapper "ets_post" to replace it. As far as I can establish, ets_post is the only rom function in use by our code or the SDK libs we use that causes calls to ets_intr_(un)lock. * Add IRAM_ATTR to ets_intr_(un)lock and ets_post wrappers. * Throw in a few comments and make ets_intr_lock_stack* static.
Arduino core for ESP8266 WiFi chip
Quick links
Arduino on ESP8266
This project brings support for the ESP8266 chip to the Arduino environment. It lets you write sketches, using familiar Arduino functions and libraries, and run them directly on ESP8266, with no external microcontroller required.
ESP8266 Arduino core comes with libraries to communicate over WiFi using TCP and UDP, set up HTTP, mDNS, SSDP, and DNS servers, do OTA updates, use a file system in flash memory, and work with SD cards, servos, SPI and I2C peripherals.
Contents
- Installing options:
- Documentation
- Issues and support
- Contributing
- License and credits
Installing with Boards Manager
Starting with 1.6.4, Arduino allows installation of third-party platform packages using Boards Manager. We have packages available for Windows, Mac OS, and Linux (32 and 64 bit).
- Install the current upstream Arduino IDE at the 1.8.7 level or later. The current version is on the Arduino website.
- Start Arduino and open the Preferences window.
- Enter
https://arduino.esp8266.com/stable/package_esp8266com_index.json
into the Additional Board Manager URLs field. You can add multiple URLs, separating them with commas. - Open Boards Manager from Tools > Board menu and install esp8266 platform (and don't forget to select your ESP8266 board from Tools > Board menu after installation).
Latest release 
Boards manager link: https://arduino.esp8266.com/stable/package_esp8266com_index.json
Documentation: https://arduino-esp8266.readthedocs.io/en/2.5.2/
Using git version (basic instructions)
- Install the current upstream Arduino IDE at the 1.8 level or later. The current version is on the Arduino website.
- Go to Arduino directory
- For Mac OS X, it is
Arduino.app
showing as the Arduino icon.
This location may be your~/Downloads
,~/Desktop
or even/Applications
.cd <application-directory>/Arduino.app/Contents/Java
- For Linux, it is ~/Arduino by default.
cd ~/Arduino
- For Mac OS X, it is
- Clone this repository into hardware/esp8266com/esp8266 directory (or clone it elsewhere and create a symlink)
cd hardware
mkdir esp8266com
cd esp8266com
git clone https://github.com/esp8266/Arduino.git esp8266
cd esp8266
git submodule update --init
- Download binary tools (you need Python 2.7)
cd esp8266/tools
python get.py
- Restart Arduino
Using PlatformIO
PlatformIO is an open source ecosystem for IoT development with a cross-platform build system, a library manager, and full support for Espressif (ESP8266) development. It works on the following popular host operating systems: macOS, Windows, Linux 32/64, and Linux ARM (like Raspberry Pi, BeagleBone, CubieBoard).
- What is PlatformIO?
- PlatformIO IDE
- PlatformIO Core (command line tool)
- Advanced usage - custom settings, uploading to SPIFFS, Over-the-Air (OTA), staging version
- Integration with Cloud and Standalone IDEs - Cloud9, Codeanywhere, Eclipse Che (Codenvy), Atom, CLion, Eclipse, Emacs, NetBeans, Qt Creator, Sublime Text, VIM, Visual Studio, and VSCode
- Project Examples
Building with make
makeEspArduino is a generic makefile for any ESP8266 Arduino project. Using make instead of the Arduino IDE makes it easier to do automated and production builds.
Documentation
Documentation for latest development version: https://arduino-esp8266.readthedocs.io/en/latest/
Issues and support
ESP8266 Community Forum is a well-established community for questions and answers about Arduino for ESP8266. If you need help, have a "How do I..." type question, have a problem with a 3rd party library not hosted in this repo, or just want to discuss how to approach a problem, please ask there.
If you find the forum useful, please consider supporting it with a donation.
If you encounter an issue which you think is a bug in the ESP8266 Arduino Core or the associated libraries, or if you want to propose an enhancement, you are welcome to submit it here on Github: https://github.com/esp8266/Arduino/issues.
Please provide as much context as possible, as well as the information requested in the issue template:
- ESP8266 Arduino core version which you are using (you can check it in Boards Manager)
- your sketch code; please wrap it into a code block, see Github markdown manual
- when encountering an issue that happens at run time, attach the serial output. Wrap it into a code block, just like the code.
- for issues that happen at compile time, enable verbose compiler output in the IDE preferences, and attach that output (also inside a code block)
- ESP8266 development board model
- IDE settings (board choice, flash size)
- etc
Contributing
For minor fixes of code and documentation, please go ahead and submit a pull request. A gentle introduction to the process can be found here.
Check out the list of issues that are easy to fix — easy issues pending. Working on them is a great way to move the project forward.
Larger changes (rewriting parts of existing code from scratch, adding new functions to the core, adding new libraries) should generally be discussed by opening an issue first.
Feature branches with lots of small commits (especially titled "oops", "fix typo", "forgot to add file", etc.) should be squashed before opening a pull request. At the same time, please refrain from putting multiple unrelated changes into a single pull request.
License and credits
Arduino IDE is developed and maintained by the Arduino team. The IDE is licensed under GPL.
ESP8266 core includes an xtensa gcc toolchain, which is also under GPL.
Esptool written by Christian Klippel is licensed under GPLv2, currently maintained by Ivan Grokhotkov: https://github.com/igrr/esptool-ck.
Espressif SDK included in this build is under Espressif MIT License.
ESP8266 core files are licensed under LGPL.
SPI Flash File System (SPIFFS) written by Peter Andersson is used in this project. It is distributed under the MIT license.
umm_malloc memory management library written by Ralph Hempel is used in this project. It is distributed under the MIT license.
SoftwareSerial library and examples written by Peter Lerup. Distributed under LGPL 2.1.
axTLS library written by Cameron Rich, built from https://github.com/igrr/axtls-8266, is used in this project. It is distributed under BSD license.
BearSSL library written by Thomas Pornin, built from https://github.com/earlephilhower/bearssl-esp8266, is used in this project. It is distributed under the MIT License.
LittleFS library written by ARM Limited and released under the BSD 3-clause license.